Instead of converting back-and-forth between the actual page and
the head page, just convert once at the end of the function where we
set the vmf->page. Saves 241 bytes of text, or 15% of the size of
filemap_fault().
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
Call page_cache_async_ra() directly instead of indirecting through
page_cache_async_readahead().
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
This saves 99 bytes of kernel text.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
Using the folio here avoids checking whether it's a tail page.
This patch mostly just enables some of the following patches.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
The only caller was already passing a head page, so this simply avoids
a call to compound_head().
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
This is all internal to filemap and saves 100 bytes of text.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
One of the callers already had a folio; the other two grow by a few
bytes, but filemap_read_page() shrinks by 50 bytes for a net reduction
of 27 bytes.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
None of the callers of find_get_pages_contig() want tail pages. They all
use order-0 pages today, but if they were converted, they'd want folios.
So just remove the call to find_subpage() instead of replacing it with
folio_page().
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
The page cache only stores folios, never tail pages. Saves 29 bytes
due to removing calls to compound_head().
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
Convert callers to cope. Saves 580 bytes of kernel text; all five
callers are reduced in size.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
Reimplement __delete_from_page_cache() as a wrapper around
__filemap_remove_folio() and delete_from_page_cache() as a wrapper
around filemap_remove_folio(). Remove the EXPORT_SYMBOL as
delete_from_page_cache() was not used by any in-tree modules.
Convert page_cache_free_page() into filemap_free_folio().
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
Pass the folio instead of a page. The page was already implicitly a
folio as it accessed page->mapping directly. Add the order of the folio
to the tracepoint, as this is important information. Also drop printing
the address of the struct page as the pfn provides better information
than the struct page address.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
Replace unaccount_page_cache_page() with filemap_unaccount_folio().
The bug handling path could be a bit more robust (eg taking into account
the mapcounts of tail pages), but it's really never supposed to happen.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
It was already assuming a head page, so this is a straightforward
conversion. Convert the one caller to call page_folio(), even though
it must currently be passing in a head page.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
Convert all three callers of put_and_wait_on_page_locked() to
folio_put_wait_locked(). This shrinks the kernel overall by 19 bytes.
filemap_update_page() shrinks by 19 bytes while __migration_entry_wait()
is unchanged. folio_put_wait_locked() is 14 bytes smaller than
put_and_wait_on_page_locked(), but pmd_migration_entry_wait() grows by
14 bytes. It removes the assumption from pmd_migration_entry_wait()
that pages cannot be larger than a PMD (which is true today, but
may be interesting to explore in the future).
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
Add some notes about how this function needs to be called.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
Pages are individually marked as suffering from hardware poisoning.
Checking that the head page is not hardware poisoned doesn't make
sense; we might be after a subpage. We check each page individually
before we use it, so this was an optimisation gone wrong.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
Hugh Dickins reported the following
My tmpfs swapping load (tweaked to use huge pages more heavily
than in real life) is far from being a realistic load: but it was
notably slowed down by your throttling mods in 5.16-rc, and this
patch makes it well again - thanks.
But: it very quickly hit NULL pointer until I changed that last
line to
if (first_pgdat)
consider_reclaim_throttle(first_pgdat, sc);
The likely issue is that huge pages are a major component of the test
workload. When this is the case, first_pgdat may never get set if
compaction is ready to continue due to this check
if (IS_ENABLED(CONFIG_COMPACTION) &&
sc->order > PAGE_ALLOC_COSTLY_ORDER &&
compaction_ready(zone, sc)) {
sc->compaction_ready = true;
continue;
}
If this was true for every zone in the zonelist, first_pgdat would never
get set resulting in a NULL pointer exception.
Link: https://lkml.kernel.org/r/20211209095453.GM3366@techsingularity.net
Fixes: 1b4e3f26f9 ("mm: vmscan: Reduce throttling due to a failure to make progress")
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Reported-by: Hugh Dickins <hughd@google.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Rik van Riel <riel@surriel.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Darrick J. Wong <djwong@kernel.org>
Cc: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Mike Galbraith, Alexey Avramov and Darrick Wong all reported similar
problems due to reclaim throttling for excessive lengths of time. In
Alexey's case, a memory hog that should go OOM quickly stalls for
several minutes before stalling. In Mike and Darrick's cases, a small
memcg environment stalled excessively even though the system had enough
memory overall.
Commit 69392a403f ("mm/vmscan: throttle reclaim when no progress is
being made") introduced the problem although commit a19594ca4a
("mm/vmscan: increase the timeout if page reclaim is not making
progress") made it worse. Systems at or near an OOM state that cannot
be recovered must reach OOM quickly and memcg should kill tasks if a
memcg is near OOM.
To address this, only stall for the first zone in the zonelist, reduce
the timeout to 1 tick for VMSCAN_THROTTLE_NOPROGRESS and only stall if
the scan control nr_reclaimed is 0, kswapd is still active and there
were excessive pages pending for writeback. If kswapd has stopped
reclaiming due to excessive failures, do not stall at all so that OOM
triggers relatively quickly. Similarly, if an LRU is simply congested,
only lightly throttle similar to NOPROGRESS.
Alexey's original case was the most straight forward
for i in {1..3}; do tail /dev/zero; done
On vanilla 5.16-rc1, this test stalled heavily, after the patch the test
completes in a few seconds similar to 5.15.
Alexey's second test case added watching a youtube video while tail runs
10 times. On 5.15, playback only jitters slightly, 5.16-rc1 stalls a
lot with lots of frames missing and numerous audio glitches. With this
patch applies, the video plays similarly to 5.15.
[lkp@intel.com: Fix W=1 build warning]
Link: https://lore.kernel.org/r/99e779783d6c7fce96448a3402061b9dc1b3b602.camel@gmx.de
Link: https://lore.kernel.org/r/20211124011954.7cab9bb4@mail.inbox.lv
Link: https://lore.kernel.org/r/20211022144651.19914-1-mgorman@techsingularity.net
Link: https://lore.kernel.org/r/20211202150614.22440-1-mgorman@techsingularity.net
Link: https://linux-regtracking.leemhuis.info/regzbot/regression/20211124011954.7cab9bb4@mail.inbox.lv/
Reported-and-tested-by: Alexey Avramov <hakavlad@inbox.lv>
Reported-and-tested-by: Mike Galbraith <efault@gmx.de>
Reported-and-tested-by: Darrick J. Wong <djwong@kernel.org>
Reported-by: kernel test robot <lkp@intel.com>
Acked-by: Hugh Dickins <hughd@google.com>
Tracked-by: Thorsten Leemhuis <regressions@leemhuis.info>
Fixes: 69392a403f ("mm/vmscan: throttle reclaim when no progress is being made")
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
DAMON debugfs interface increases the reference counts of 'struct pid's
for targets from the 'target_ids' file write callback
('dbgfs_target_ids_write()'), but decreases the counts only in DAMON
monitoring termination callback ('dbgfs_before_terminate()').
Therefore, when 'target_ids' file is repeatedly written without DAMON
monitoring start/termination, the reference count is not decreased and
therefore memory for the 'struct pid' cannot be freed. This commit
fixes this issue by decreasing the reference counts when 'target_ids' is
written.
Link: https://lkml.kernel.org/r/20211229124029.23348-1-sj@kernel.org
Fixes: 4bc05954d0 ("mm/damon: implement a debugfs-based user space interface")
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: <stable@vger.kernel.org> [5.15+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Hulk Robot reported a panic in put_page_testzero() when testing
madvise() with MADV_SOFT_OFFLINE. The BUG() is triggered when retrying
get_any_page(). This is because we keep MF_COUNT_INCREASED flag in
second try but the refcnt is not increased.
page dumped because: VM_BUG_ON_PAGE(page_ref_count(page) == 0)
------------[ cut here ]------------
kernel BUG at include/linux/mm.h:737!
invalid opcode: 0000 [#1] PREEMPT SMP
CPU: 5 PID: 2135 Comm: sshd Tainted: G B 5.16.0-rc6-dirty #373
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014
RIP: release_pages+0x53f/0x840
Call Trace:
free_pages_and_swap_cache+0x64/0x80
tlb_flush_mmu+0x6f/0x220
unmap_page_range+0xe6c/0x12c0
unmap_single_vma+0x90/0x170
unmap_vmas+0xc4/0x180
exit_mmap+0xde/0x3a0
mmput+0xa3/0x250
do_exit+0x564/0x1470
do_group_exit+0x3b/0x100
__do_sys_exit_group+0x13/0x20
__x64_sys_exit_group+0x16/0x20
do_syscall_64+0x34/0x80
entry_SYSCALL_64_after_hwframe+0x44/0xae
Modules linked in:
---[ end trace e99579b570fe0649 ]---
RIP: 0010:release_pages+0x53f/0x840
Link: https://lkml.kernel.org/r/20211221074908.3910286-1-liushixin2@huawei.com
Fixes: b94e02822d ("mm,hwpoison: try to narrow window race for free pages")
Signed-off-by: Liu Shixin <liushixin2@huawei.com>
Reported-by: Hulk Robot <hulkci@huawei.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Acked-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
DAMON debugfs interface iterates current monitoring targets in
'dbgfs_target_ids_read()' while holding the corresponding
'kdamond_lock'. However, it also destructs the monitoring targets in
'dbgfs_before_terminate()' without holding the lock. This can result in
a use_after_free bug. This commit avoids the race by protecting the
destruction with the corresponding 'kdamond_lock'.
Link: https://lkml.kernel.org/r/20211221094447.2241-1-sj@kernel.org
Reported-by: Sangwoo Bae <sangwoob@amazon.com>
Fixes: 4bc05954d0 ("mm/damon: implement a debugfs-based user space interface")
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: <stable@vger.kernel.org> [5.15.x]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When a memory error hits a tail page of a free hugepage,
__page_handle_poison() is expected to be called to isolate the error in
4kB unit, but it's not called due to the outdated if-condition in
memory_failure_hugetlb(). This loses the chance to isolate the error in
the finer unit, so it's not optimal. Drop the condition.
This "(p != head && TestSetPageHWPoison(head)" condition is based on the
old semantics of PageHWPoison on hugepage (where PG_hwpoison flag was
set on the subpage), so it's not necessray any more. By getting to set
PG_hwpoison on head page for hugepages, concurrent error events on
different subpages in a single hugepage can be prevented by
TestSetPageHWPoison(head) at the beginning of memory_failure_hugetlb().
So dropping the condition should not reopen the race window originally
mentioned in commit b985194c8c ("hwpoison, hugetlb:
lock_page/unlock_page does not match for handling a free hugepage")
[naoya.horiguchi@linux.dev: fix "HardwareCorrupted" counter]
Link: https://lkml.kernel.org/r/20211220084851.GA1460264@u2004
Link: https://lkml.kernel.org/r/20211210110208.879740-1-naoya.horiguchi@linux.dev
Signed-off-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Reported-by: Fei Luo <luofei@unicloud.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: <stable@vger.kernel.org> [5.14+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull percpu fixes from Dennis Zhou:
"This contains a fix for SMP && !MMU archs for percpu which has been
tested by arm and sh. It seems in the past they have gotten away with
it due to mapping of vm functions to km functions, but this fell apart
a few releases ago and was just reported recently.
The other is just a minor dependency clean up.
I think queued up right now by Andrew is a fix in percpu that papers
of what seems to be a bug in hotplug for a special situation with
memoryless nodes. Michal Hocko is digging into it further"
* 'for-5.16-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/dennis/percpu:
percpu_ref: Replace kernel.h with the necessary inclusions
percpu: km: ensure it is used with NOMMU (either UP or SMP)
Initialize min_ratio if it is set during bdi unregistration. This can
prevent problems that may occur a when bdi is removed without resetting
min_ratio.
For example.
1) insert external sdcard
2) set external sdcard's min_ratio 70
3) remove external sdcard without setting min_ratio 0
4) insert external sdcard
5) set external sdcard's min_ratio 70 << error occur(can't set)
Because when an sdcard is removed, the present bdi_min_ratio value will
remain. Currently, the only way to reset bdi_min_ratio is to reboot.
[akpm@linux-foundation.org: tweak comment and coding style]
Link: https://lkml.kernel.org/r/20211021161942.5983-1-mj0123.lee@samsung.com
Signed-off-by: Manjong Lee <mj0123.lee@samsung.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Changheun Lee <nanich.lee@samsung.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: <seunghwan.hyun@samsung.com>
Cc: <sookwan7.kim@samsung.com>
Cc: <yt0928.kim@samsung.com>
Cc: <junho89.kim@samsung.com>
Cc: <jisoo2146.oh@samsung.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Preallocation of gigantic pages can't work bacause of commit
b5389086ad ("hugetlbfs: extend the definition of hugepages parameter
to support node allocation"). When nid is NUMA_NO_NODE(-1),
alloc_bootmem_huge_page will always return without doing allocation.
Fix this by adding more check.
Link: https://lkml.kernel.org/r/20211129133803.15653-1-yaozhenguo1@gmail.com
Fixes: b5389086ad ("hugetlbfs: extend the definition of hugepages parameter to support node allocation")
Signed-off-by: Zhenguo Yao <yaozhenguo1@gmail.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Tested-by: Maxim Levitsky <mlevitsk@redhat.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
All the calls to mod_objcg_mlstate(), get_obj_stock() and
put_obj_stock() are done by functions defined within the same "#ifdef
CONFIG_MEMCG_KMEM" compilation block. When CONFIG_MEMCG_KMEM isn't
defined, the following compilation warnings will be issued [1] and [2].
mm/memcontrol.c:785:20: warning: unused function 'mod_objcg_mlstate'
mm/memcontrol.c:2113:33: warning: unused function 'get_obj_stock'
Fix these warning by moving those functions to under the same
CONFIG_MEMCG_KMEM compilation block. There is no functional change.
[1] https://lore.kernel.org/lkml/202111272014.WOYNLUV6-lkp@intel.com/
[2] https://lore.kernel.org/lkml/202111280551.LXsWYt1T-lkp@intel.com/
Link: https://lkml.kernel.org/r/20211129161140.306488-1-longman@redhat.com
Fixes: 559271146e ("mm/memcg: optimize user context object stock access")
Fixes: 68ac5b3c8d ("mm/memcg: cache vmstat data in percpu memcg_stock_pcp")
Signed-off-by: Waiman Long <longman@redhat.com>
Reported-by: kernel test robot <lkp@intel.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Roman Gushchin <guro@fb.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
On big-endian s390, the alloc/free_traces attributes produce endless
output, because of always 0 idx in slab_debugfs_show().
idx is de-referenced from *v, which points to a loff_t value, with
unsigned int idx = *(unsigned int *)v;
This will only give the upper 32 bits on big-endian, which remain 0.
Instead of only fixing this de-reference, during discussion it seemed
more appropriate to change the seq_ops so that they use an explicit
iterator in private loc_track struct.
This patch adds idx to loc_track, which will also fix the endianness
bug.
Link: https://lore.kernel.org/r/20211117193932.4049412-1-gerald.schaefer@linux.ibm.com
Link: https://lkml.kernel.org/r/20211126171848.17534-1-gerald.schaefer@linux.ibm.com
Fixes: 64dd68497b ("mm: slub: move sysfs slab alloc/free interfaces to debugfs")
Signed-off-by: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Reported-by: Steffen Maier <maier@linux.ibm.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Faiyaz Mohammed <faiyazm@codeaurora.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
A couple of test functions in DAMON virtual address space monitoring
primitives implementation has unnecessary damon_ctx variables. This
commit removes those.
Link: https://lkml.kernel.org/r/20211201150440.1088-7-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Brendan Higgins <brendanhiggins@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
On some configuration[1], 'damon_test_split_evenly()' kunit test
function has >1024 bytes frame size, so below build warning is
triggered:
CC mm/damon/vaddr.o
In file included from mm/damon/vaddr.c:672:
mm/damon/vaddr-test.h: In function 'damon_test_split_evenly':
mm/damon/vaddr-test.h:309:1: warning: the frame size of 1064 bytes is larger than 1024 bytes [-Wframe-larger-than=]
309 | }
| ^
This commit fixes the warning by separating the common logic in the
function.
[1] https://lore.kernel.org/linux-mm/202111182146.OV3C4uGr-lkp@intel.com/
Link: https://lkml.kernel.org/r/20211201150440.1088-6-sj@kernel.org
Fixes: 17ccae8bb5 ("mm/damon: add kunit tests")
Signed-off-by: SeongJae Park <sj@kernel.org>
Reported-by: kernel test robot <lkp@intel.com>
Cc: Brendan Higgins <brendanhiggins@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The DAMON virtual address space monitoring primitive prints a warning
message for wrong DAMOS action. However, it is not essential as the
code returns appropriate failure in the case. This commit removes the
message to make the log clean.
Link: https://lkml.kernel.org/r/20211201150440.1088-5-sj@kernel.org
Fixes: 6dea8add4d ("mm/damon/vaddr: support DAMON-based Operation Schemes")
Signed-off-by: SeongJae Park <sj@kernel.org>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Cc: Brendan Higgins <brendanhiggins@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
DAMON core prints error messages when damon_target object creation is
failed or wrong monitoring attributes are given. Because appropriate
error code is returned for each case, the messages are not essential.
Also, because the code path can be triggered with user-specified input,
this could result in kernel log mistakenly being messy. To avoid the
case, this commit removes the messages.
Link: https://lkml.kernel.org/r/20211201150440.1088-4-sj@kernel.org
Fixes: 4bc05954d0 ("mm/damon: implement a debugfs-based user space interface")
Fixes: b9a6ac4e4e ("mm/damon: adaptively adjust regions")
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Brendan Higgins <brendanhiggins@google.com>
Cc: kernel test robot <lkp@intel.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When wrong scheme action is requested via the debugfs interface, DAMON
prints an error message. Because the function returns error code, this
is not really needed. Because the code path is triggered by the user
specified input, this can result in kernel log mistakenly being messy.
To avoid the case, this commit removes the message.
Link: https://lkml.kernel.org/r/20211201150440.1088-3-sj@kernel.org
Fixes: af122dd8f3 ("mm/damon/dbgfs: support DAMON-based Operation Schemes")
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Brendan Higgins <brendanhiggins@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "mm/damon: Trivial fixups and improvements".
This patchset contains trivial fixups and improvements for DAMON and its
kunit/kselftest tests.
This patch (of 11):
DAMON is using hrtimer if requested sleep time is <=100ms, while the
suggested threshold[1] is <=20ms. This commit applies the threshold.
[1] Documentation/timers/timers-howto.rst
Link: https://lkml.kernel.org/r/20211201150440.1088-2-sj@kernel.org
Fixes: ee801b7dd7 ("mm/damon/schemes: activate schemes based on a watermarks mechanism")
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Because DAMON sleeps in uninterruptible mode, /proc/loadavg reports fake
load while DAMON is turned on, though it is doing nothing. This can
confuse users[1]. To avoid the case, this commit makes DAMON sleeps in
idle mode.
[1] https://lore.kernel.org/all/11868371.O9o76ZdvQC@natalenko.name/
Link: https://lkml.kernel.org/r/20211126145015.15862-3-sj@kernel.org
Fixes: 2224d84854 ("mm: introduce Data Access MONitor (DAMON)")
Reported-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Signed-off-by: SeongJae Park <sj@kernel.org>
Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pages are individually marked as suffering from hardware poisoning.
Checking that the head page is not hardware poisoned doesn't make
sense; we might be after a subpage. We check each page individually
before we use it, so this was an optimisation gone wrong. It will
cause us to fall back to the slow path when there was no need to do
that
Link: https://lkml.kernel.org/r/20211120174429.2596303-1-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Yang Shi <shy828301@gmail.com>
Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Some memory management calls imply memory barriers that are required to
avoid false positives. For example, without the correct instrumentation,
we could observe data races of the following variant:
T0 | T1
------------------------+------------------------
|
*a = 42; ---+ |
kfree(a); | |
| | b = kmalloc(..); // b == a
<reordered> <-+ | *b = 42; // not a data race!
|
Therefore, instrument memory barriers in all allocator code currently
not being instrumented in a default build.
Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Daniel Borkmann says:
====================
bpf 2021-12-08
We've added 12 non-merge commits during the last 22 day(s) which contain
a total of 29 files changed, 659 insertions(+), 80 deletions(-).
The main changes are:
1) Fix an off-by-two error in packet range markings and also add a batch of
new tests for coverage of these corner cases, from Maxim Mikityanskiy.
2) Fix a compilation issue on MIPS JIT for R10000 CPUs, from Johan Almbladh.
3) Fix two functional regressions and a build warning related to BTF kfunc
for modules, from Kumar Kartikeya Dwivedi.
4) Fix outdated code and docs regarding BPF's migrate_disable() use on non-
PREEMPT_RT kernels, from Sebastian Andrzej Siewior.
5) Add missing includes in order to be able to detangle cgroup vs bpf header
dependencies, from Jakub Kicinski.
6) Fix regression in BPF sockmap tests caused by missing detachment of progs
from sockets when they are removed from the map, from John Fastabend.
7) Fix a missing "no previous prototype" warning in x86 JIT caused by BPF
dispatcher, from Björn Töpel.
* https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf:
bpf: Add selftests to cover packet access corner cases
bpf: Fix the off-by-two error in range markings
treewide: Add missing includes masked by cgroup -> bpf dependency
tools/resolve_btfids: Skip unresolved symbol warning for empty BTF sets
bpf: Fix bpf_check_mod_kfunc_call for built-in modules
bpf: Make CONFIG_DEBUG_INFO_BTF depend upon CONFIG_BPF_SYSCALL
mips, bpf: Fix reference to non-existing Kconfig symbol
bpf: Make sure bpf_disable_instrumentation() is safe vs preemption.
Documentation/locking/locktypes: Update migrate_disable() bits.
bpf, sockmap: Re-evaluate proto ops when psock is removed from sockmap
bpf, sockmap: Attach map progs to psock early for feature probes
bpf, x86: Fix "no previous prototype" warning
====================
Link: https://lore.kernel.org/r/20211208155125.11826-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Currently, NOMMU pull km allocator via !SMP dependency because most of
them are UP, yet for SMP+NOMMU vm allocator gets pulled which:
* may lead to broken build [1]
* ...or not working runtime due to [2]
It looks like SMP+NOMMU case was overlooked in bbddff0545 ("percpu:
use percpu allocator on UP too") so restore that.
[1]
For ARM SMP+NOMMU (R-class cores)
arm-none-linux-gnueabihf-ld: mm/percpu.o: in function `pcpu_post_unmap_tlb_flush':
mm/percpu-vm.c:188: undefined reference to `flush_tlb_kernel_range'
[2]
static inline
int vmap_pages_range_noflush(unsigned long addr, unsigned long end,
pgprot_t prot, struct page **pages, unsigned int page_shift)
{
return -EINVAL;
}
Signed-off-by: Vladimir Murzin <vladimir.murzin@arm.com>
Tested-by: Rob Landley <rob@landley.net>
Tested-by: Rich Felker <dalias@libc.org>
[Dennis: use depends instead of default for condition]
Signed-off-by: Dennis Zhou <dennis@kernel.org>
No driver is left using the external pgmap refcount, so remove the
code to support it.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Link: https://lore.kernel.org/r/20211028151017.50234-1-hch@lst.de
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
No functional changes in this patch, just in preparation for efficiently
calling this light function from the block O_DIRECT handling.
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
cgroup.h (therefore swap.h, therefore half of the universe)
includes bpf.h which in turn includes module.h and slab.h.
Since we're about to get rid of that dependency we need
to clean things up.
v2: drop the cpu.h include from cacheinfo.h, it's not necessary
and it makes riscv sensitive to ordering of include files.
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Krzysztof Wilczyński <kw@linux.com>
Acked-by: Peter Chen <peter.chen@kernel.org>
Acked-by: SeongJae Park <sj@kernel.org>
Acked-by: Jani Nikula <jani.nikula@intel.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/all/20211120035253.72074-1-kuba@kernel.org/ # v1
Link: https://lore.kernel.org/all/20211120165528.197359-1-kuba@kernel.org/ # cacheinfo discussion
Link: https://lore.kernel.org/bpf/20211202203400.1208663-1-kuba@kernel.org
- Fix compilation warnings on csky and sparc
- Rename multipage folios to large folios
- Rename AS_THP_SUPPORT and FS_THP_SUPPORT
- Add functions to zero portions of a folio
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Merge tag 'folio-5.16b' of git://git.infradead.org/users/willy/pagecache
Pull folio fixes from Matthew Wilcox:
"In the course of preparing the folio changes for iomap for next merge
window, we discovered some problems that would be nice to address now:
- Renaming multi-page folios to large folios.
mapping_multi_page_folio_support() is just a little too long, so we
settled on mapping_large_folio_support(). That meant renaming, eg
folio_test_multi() to folio_test_large().
Rename AS_THP_SUPPORT to match
- I hadn't included folio wrappers for zero_user_segments(), etc.
Also, multi-page^W^W large folio support is now independent of
CONFIG_TRANSPARENT_HUGEPAGE, so machines with HIGHMEM always need
to fall back to the out-of-line zero_user_segments().
Remove FS_THP_SUPPORT to match
- The build bots finally got round to telling me that I missed a
couple of architectures when adding flush_dcache_folio(). Christoph
suggested that we just add linux/cacheflush.h and not rely on
asm-generic/cacheflush.h"
* tag 'folio-5.16b' of git://git.infradead.org/users/willy/pagecache:
mm: Add functions to zero portions of a folio
fs: Rename AS_THP_SUPPORT and mapping_thp_support
fs: Remove FS_THP_SUPPORT
mm: Remove folio_test_single
mm: Rename folio_test_multi to folio_test_large
Add linux/cacheflush.h
We must flush the TLB before releasing i_mmap_rwsem to avoid the
potential reuse of an unshared PMDs page. This is not true in the case
of move_hugetlb_page_tables(). The last reference on the page table can
therefore be dropped before the TLB flush took place.
Prevent it by reordering the operations and flushing the TLB before
releasing i_mmap_rwsem.
Fixes: 550a7d60bd ("mm, hugepages: add mremap() support for hugepage backed vma")
Signed-off-by: Nadav Amit <namit@vmware.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mina Almasry <almasrymina@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When __unmap_hugepage_range() calls to huge_pmd_unshare() succeed, a TLB
flush is missing. This TLB flush must be performed before releasing the
i_mmap_rwsem, in order to prevent an unshared PMDs page from being
released and reused before the TLB flush took place.
Arguably, a comprehensive solution would use mmu_gather interface to
batch the TLB flushes and the PMDs page release, however it is not an
easy solution: (1) try_to_unmap_one() and try_to_migrate_one() also call
huge_pmd_unshare() and they cannot use the mmu_gather interface; and (2)
deferring the release of the page reference for the PMDs page until
after i_mmap_rwsem is dropeed can confuse huge_pmd_unshare() into
thinking PMDs are shared when they are not.
Fix __unmap_hugepage_range() by adding the missing TLB flush, and
forcing a flush when unshare is successful.
Fixes: 24669e5847 ("hugetlb: use mmu_gather instead of a temporary linked list for accumulating pages)" # 3.6
Signed-off-by: Nadav Amit <namit@vmware.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The kmap_local conversion broke the ARM architecture, because the new
code assumes that all PTEs used for creating kmaps form a linear array
in memory, and uses array indexing to look up the kmap PTE belonging to
a certain kmap index.
On ARM, this cannot work, not only because the PTE pages may be
non-adjacent in memory, but also because ARM/!LPAE interleaves hardware
entries and extended entries (carrying software-only bits) in a way that
is not compatible with array indexing.
Fortunately, this only seems to affect configurations with more than 8
CPUs, due to the way the per-CPU kmap slots are organized in memory.
Work around this by permitting an architecture to set a Kconfig symbol
that signifies that the kmap PTEs do not form a lineary array in memory,
and so the only way to locate the appropriate one is to walk the page
tables.
Link: https://lore.kernel.org/linux-arm-kernel/20211026131249.3731275-1-ardb@kernel.org/
Link: https://lkml.kernel.org/r/20211116094737.7391-1-ardb@kernel.org
Fixes: 2a15ba82fa ("ARM: highmem: Switch to generic kmap atomic")
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reported-by: Quanyang Wang <quanyang.wang@windriver.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
DAMON debugfs is supposed to protect dbgfs_ctxs, dbgfs_nr_ctxs, and
dbgfs_dirs using damon_dbgfs_lock. However, some of the code is
accessing the variables without the protection. This fixes it by
protecting all such accesses.
Link: https://lkml.kernel.org/r/20211110145758.16558-3-sj@kernel.org
Fixes: 75c1c2b53c ("mm/damon/dbgfs: support multiple contexts")
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "DAMON fixes".
This patch (of 2):
DAMON users can trigger below warning in '__alloc_pages()' by invoking
write() to some DAMON debugfs files with arbitrarily high count
argument, because DAMON debugfs interface allocates some buffers based
on the user-specified 'count'.
if (unlikely(order >= MAX_ORDER)) {
WARN_ON_ONCE(!(gfp & __GFP_NOWARN));
return NULL;
}
Because the DAMON debugfs interface code checks failure of the
'kmalloc()', this commit simply suppresses the warnings by adding
'__GFP_NOWARN' flag.
Link: https://lkml.kernel.org/r/20211110145758.16558-1-sj@kernel.org
Link: https://lkml.kernel.org/r/20211110145758.16558-2-sj@kernel.org
Fixes: 4bc05954d0 ("mm/damon: implement a debugfs-based user space interface")
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently in the is_continue case in hugetlb_mcopy_atomic_pte(), if we
bail out using "goto out_release_unlock;" in the cases where idx >=
size, or !huge_pte_none(), the code will detect that new_pagecache_page
== false, and so call restore_reserve_on_error(). In this case I see
restore_reserve_on_error() delete the reservation, and the following
call to remove_inode_hugepages() will increment h->resv_hugepages
causing a 100% reproducible leak.
We should treat the is_continue case similar to adding a page into the
pagecache and set new_pagecache_page to true, to indicate that there is
no reservation to restore on the error path, and we need not call
restore_reserve_on_error(). Rename new_pagecache_page to
page_in_pagecache to make that clear.
Link: https://lkml.kernel.org/r/20211117193825.378528-1-almasrymina@google.com
Fixes: c7b1850dfb ("hugetlb: don't pass page cache pages to restore_reserve_on_error")
Signed-off-by: Mina Almasry <almasrymina@google.com>
Reported-by: James Houghton <jthoughton@google.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Wei Xu <weixugc@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When hugetlb_vm_op_open() is called during copy_vma(), we may take the
reference to resv_map->css. Later, when clearing the reservation
pointer of old_vma after transferring it to new_vma, we forget to drop
the reference to resv_map->css. This leads to a reference leak of css.
Fixes this by adding a check to drop reservation css reference in
clear_vma_resv_huge_pages()
Link: https://lkml.kernel.org/r/20211113154412.91134-1-minhquangbui99@gmail.com
Fixes: 550a7d60bd ("mm, hugepages: add mremap() support for hugepage backed vma")
Signed-off-by: Bui Quang Minh <minhquangbui99@gmail.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Mina Almasry <almasrymina@google.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When kmemleak is enabled for SLOB, system does not boot and does not
print anything to the console. At the very early stage in the boot
process we hit infinite recursion from kmemleak_init() and eventually
kernel crashes.
kmemleak_init() specifies SLAB_NOLEAKTRACE for KMEM_CACHE(), but
kmem_cache_create_usercopy() removes it because CACHE_CREATE_MASK is not
valid for SLOB.
Let's fix CACHE_CREATE_MASK and make kmemleak work with SLOB
Link: https://lkml.kernel.org/r/20211115020850.3154366-1-rkovhaev@gmail.com
Fixes: d8843922fb ("slab: Ignore internal flags in cache creation")
Signed-off-by: Rustam Kovhaev <rkovhaev@gmail.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Glauber Costa <glommer@parallels.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
After the memory is freed, it can be immediately allocated by other
CPUs, before the "free" trace report has been emitted. This causes
inaccurate traces.
For example, if the following sequence of events occurs:
CPU 0 CPU 1
(1) alloc xxxxxx
(2) free xxxxxx
(3) alloc xxxxxx
(4) free xxxxxx
Then they will be inaccurately reported via tracing, so that they appear
to have happened in this order:
CPU 0 CPU 1
(1) alloc xxxxxx
(2) alloc xxxxxx
(3) free xxxxxx
(4) free xxxxxx
This makes it look like CPU 1 somehow managed to allocate memory that
CPU 0 still had allocated for itself.
In order to avoid this, emit the "free xxxxxx" tracing report just
before the actual call to free the memory, instead of just after it.
Link: https://lkml.kernel.org/r/374eb75d-7404-8721-4e1e-65b0e5b17279@huawei.com
Signed-off-by: Yunfeng Ye <yeyunfeng@huawei.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
While free_unref_page_list() puts pages onto the CPU local LRU list, it
does not remove them from the list they were passed in on. That makes
the list_head appear to be non-empty, and would lead to various
corruption problems if we didn't have an assertion that the list was
empty.
Reinitialise the list after calling free_unref_page_list() to avoid this
problem.
Link: https://lkml.kernel.org/r/YYp40A2lNrxaZji8@casper.infradead.org
Fixes: 988c69f1bc ("mm: optimise put_pages_list()")
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Steve French <stfrench@microsoft.com>
Reported-by: Namjae Jeon <linkinjeon@kernel.org>
Tested-by: Steve French <stfrench@microsoft.com>
Tested-by: Namjae Jeon <linkinjeon@kernel.org>
Cc: Steve French <smfrench@gmail.com>
Cc: Hyeoncheol Lee <hyc.lee@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
These functions are wrappers around zero_user_segments(), which means
that zero_user_segments() can now be called for compound pages even when
CONFIG_TRANSPARENT_HUGEPAGE is disabled.
Use 'xend' as the name of the parameter to indicate that this is an
excluded end, not the more usual included end. Excluding the end makes
more sense to the callers, but can cause confusion to readers who are
more used to seeing included ends.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Instead of setting a bit in the fs_flags to set a bit in the
address_space, set the bit in the address_space directly.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Add a call inside memory_failure() to call the arch specific code
to check if the address is an SGX EPC page and handle it.
Note the SGX EPC pages do not have a "struct page" entry, so the hook
goes in at the same point as the device mapping hook.
Pull the call to acquire the mutex earlier so the SGX errors are also
protected.
Make set_mce_nospec() skip SGX pages when trying to adjust
the 1:1 map.
Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Reviewed-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Tested-by: Reinette Chatre <reinette.chatre@intel.com>
Link: https://lkml.kernel.org/r/20211026220050.697075-6-tony.luck@intel.com
This reverts commit b9d02f1bdd.
The error handling of that patch was fundamentally broken, and it needs
to be entirely re-done.
For example, in shmem_write_begin() it would call shmem_getpage(), then
ignore the error return from that, and look at the page pointer contents
instead.
And in shmem_read_mapping_page_gfp(), the patch tested PageHWPoison() on
a page pointer that two lines earlier had potentially been set as an
error pointer.
These issues could be individually fixed, but when it has this many
issues, I'm just reverting it instead of waiting for fixes.
Link: https://lore.kernel.org/linux-mm/20211111084617.6746-1-ajaygargnsit@gmail.com/
Reported-by: Ajay Garg <ajaygargnsit@gmail.com>
Reported-by: Jens Axboe <axboe@kernel.dk>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Merge tag 'netfs-folio-20211111' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs
Pull netfs, 9p, afs and ceph (partial) foliation from David Howells:
"This converts netfslib, 9p and afs to use folios. It also partially
converts ceph so that it uses folios on the boundaries with netfslib.
To help with this, a couple of folio helper functions are added in the
first two patches.
These patches don't touch fscache and cachefiles as I intend to remove
all the code that deals with pages directly from there. Only nfs and
cifs are using the old fscache I/O API now. The new API uses iov_iter
instead.
Thanks to Jeff Layton, Dominique Martinet and AuriStor for testing and
retesting the patches"
* tag 'netfs-folio-20211111' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs:
afs: Use folios in directory handling
netfs, 9p, afs, ceph: Use folios
folio: Add a function to get the host inode for a folio
folio: Add a function to change the private data attached to a folio
Merge more updates from Andrew Morton:
"The post-linux-next material.
7 patches.
Subsystems affected by this patch series (all mm): debug,
slab-generic, migration, memcg, and kasan"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
kasan: add kasan mode messages when kasan init
mm: unexport {,un}lock_page_memcg
mm: unexport folio_memcg_{,un}lock
mm/migrate.c: remove MIGRATE_PFN_LOCKED
mm: migrate: simplify the file-backed pages validation when migrating its mapping
mm: allow only SLUB on PREEMPT_RT
mm/page_owner.c: modify the type of argument "order" in some functions
and netfilter.
Current release - regressions:
- bpf: do not reject when the stack read size is different
from the tracked scalar size
- net: fix premature exit from NAPI state polling in napi_disable()
- riscv, bpf: fix RV32 broken build, and silence RV64 warning
Current release - new code bugs:
- net: fix possible NULL deref in sock_reserve_memory
- amt: fix error return code in amt_init(); fix stopping the workqueue
- ax88796c: use the correct ioctl callback
Previous releases - always broken:
- bpf: stop caching subprog index in the bpf_pseudo_func insn
- security: fixups for the security hooks in sctp
- nfc: add necessary privilege flags in netlink layer, limit operations
to admin only
- vsock: prevent unnecessary refcnt inc for non-blocking connect
- net/smc: fix sk_refcnt underflow on link down and fallback
- nfnetlink_queue: fix OOB when mac header was cleared
- can: j1939: ignore invalid messages per standard
- bpf, sockmap:
- fix race in ingress receive verdict with redirect to self
- fix incorrect sk_skb data_end access when src_reg = dst_reg
- strparser, and tls are reusing qdisc_skb_cb and colliding
- ethtool: fix ethtool msg len calculation for pause stats
- vlan: fix a UAF in vlan_dev_real_dev() when ref-holder tries
to access an unregistering real_dev
- udp6: make encap_rcv() bump the v6 not v4 stats
- drv: prestera: add explicit padding to fix m68k build
- drv: felix: fix broken VLAN-tagged PTP under VLAN-aware bridge
- drv: mvpp2: fix wrong SerDes reconfiguration order
Misc & small latecomers:
- ipvs: auto-load ipvs on genl access
- mctp: sanity check the struct sockaddr_mctp padding fields
- libfs: support RENAME_EXCHANGE in simple_rename()
- avoid double accounting for pure zerocopy skbs
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Merge tag 'net-5.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Pull networking fixes from Jakub Kicinski:
"Including fixes from bpf, can and netfilter.
Current release - regressions:
- bpf: do not reject when the stack read size is different from the
tracked scalar size
- net: fix premature exit from NAPI state polling in napi_disable()
- riscv, bpf: fix RV32 broken build, and silence RV64 warning
Current release - new code bugs:
- net: fix possible NULL deref in sock_reserve_memory
- amt: fix error return code in amt_init(); fix stopping the
workqueue
- ax88796c: use the correct ioctl callback
Previous releases - always broken:
- bpf: stop caching subprog index in the bpf_pseudo_func insn
- security: fixups for the security hooks in sctp
- nfc: add necessary privilege flags in netlink layer, limit
operations to admin only
- vsock: prevent unnecessary refcnt inc for non-blocking connect
- net/smc: fix sk_refcnt underflow on link down and fallback
- nfnetlink_queue: fix OOB when mac header was cleared
- can: j1939: ignore invalid messages per standard
- bpf, sockmap:
- fix race in ingress receive verdict with redirect to self
- fix incorrect sk_skb data_end access when src_reg = dst_reg
- strparser, and tls are reusing qdisc_skb_cb and colliding
- ethtool: fix ethtool msg len calculation for pause stats
- vlan: fix a UAF in vlan_dev_real_dev() when ref-holder tries to
access an unregistering real_dev
- udp6: make encap_rcv() bump the v6 not v4 stats
- drv: prestera: add explicit padding to fix m68k build
- drv: felix: fix broken VLAN-tagged PTP under VLAN-aware bridge
- drv: mvpp2: fix wrong SerDes reconfiguration order
Misc & small latecomers:
- ipvs: auto-load ipvs on genl access
- mctp: sanity check the struct sockaddr_mctp padding fields
- libfs: support RENAME_EXCHANGE in simple_rename()
- avoid double accounting for pure zerocopy skbs"
* tag 'net-5.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (123 commits)
selftests/net: udpgso_bench_rx: fix port argument
net: wwan: iosm: fix compilation warning
cxgb4: fix eeprom len when diagnostics not implemented
net: fix premature exit from NAPI state polling in napi_disable()
net/smc: fix sk_refcnt underflow on linkdown and fallback
net/mlx5: Lag, fix a potential Oops with mlx5_lag_create_definer()
gve: fix unmatched u64_stats_update_end()
net: ethernet: lantiq_etop: Fix compilation error
selftests: forwarding: Fix packet matching in mirroring selftests
vsock: prevent unnecessary refcnt inc for nonblocking connect
net: marvell: mvpp2: Fix wrong SerDes reconfiguration order
net: ethernet: ti: cpsw_ale: Fix access to un-initialized memory
net: stmmac: allow a tc-taprio base-time of zero
selftests: net: test_vxlan_under_vrf: fix HV connectivity test
net: hns3: allow configure ETS bandwidth of all TCs
net: hns3: remove check VF uc mac exist when set by PF
net: hns3: fix some mac statistics is always 0 in device version V2
net: hns3: fix kernel crash when unload VF while it is being reset
net: hns3: sync rx ring head in echo common pull
net: hns3: fix pfc packet number incorrect after querying pfc parameters
...
There are multiple kasan modes. It makes sense that we add some
messages to know which kasan mode is active when booting up [1].
Link: https://bugzilla.kernel.org/show_bug.cgi?id=212195 [1]
Link: https://lkml.kernel.org/r/20211020094850.4113-1-Kuan-Ying.Lee@mediatek.com
Signed-off-by: Kuan-Ying Lee <Kuan-Ying.Lee@mediatek.com>
Reviewed-by: Marco Elver <elver@google.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Matthias Brugger <matthias.bgg@gmail.com>
Cc: Chinwen Chang <chinwen.chang@mediatek.com>
Cc: Yee Lee <yee.lee@mediatek.com>
Cc: Nicholas Tang <nicholas.tang@mediatek.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
These are only used in built-in core mm code.
Link: https://lkml.kernel.org/r/20210820095815.445392-3-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "unexport memcg locking helpers".
Neither the old page-based nor the new folio-based memcg locking helpers
are used in modular code at all, so drop the exports.
This patch (of 2):
folio_memcg_{,un}lock are only used in built-in core mm code.
Link: https://lkml.kernel.org/r/20210820095815.445392-1-hch@lst.de
Link: https://lkml.kernel.org/r/20210820095815.445392-2-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
MIGRATE_PFN_LOCKED is used to indicate to migrate_vma_prepare() that a
source page was already locked during migrate_vma_collect(). If it
wasn't then the a second attempt is made to lock the page. However if
the first attempt failed it's unlikely a second attempt will succeed,
and the retry adds complexity. So clean this up by removing the retry
and MIGRATE_PFN_LOCKED flag.
Destination pages are also meant to have the MIGRATE_PFN_LOCKED flag
set, but nothing actually checks that.
Link: https://lkml.kernel.org/r/20211025041608.289017-1-apopple@nvidia.com
Signed-off-by: Alistair Popple <apopple@nvidia.com>
Reviewed-by: Ralph Campbell <rcampbell@nvidia.com>
Acked-by: Felix Kuehling <Felix.Kuehling@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Ben Skeggs <bskeggs@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There is no need to validate the file-backed page's refcount before
trying to freeze the page's expected refcount, instead we can rely on
the folio_ref_freeze() to validate if the page has the expected refcount
before migrating its mapping.
Moreover we are always under the page lock when migrating the page
mapping, which means nowhere else can remove it from the page cache, so
we can remove the xas_load() validation under the i_pages lock.
Link: https://lkml.kernel.org/r/cover.1629447552.git.baolin.wang@linux.alibaba.com
Link: https://lkml.kernel.org/r/df4c129fd8e86a95dbc55f4663d77441cc0d3bd1.1629447552.git.baolin.wang@linux.alibaba.com
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Suggested-by: Matthew Wilcox <willy@infradead.org>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Alistair Popple <apopple@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The type of "order" in struct page_owner is unsigned short.
However, it is unsigned int in the following 3 functions:
__reset_page_owner
__set_page_owner_handle
__set_page_owner_handle
The type of "order" in argument list is unsigned int, which is
inconsistent.
[akpm@linux-foundation.org: update include/linux/page_owner.h]
Link: https://lkml.kernel.org/r/20211020125945.47792-1-caoyixuan2019@email.szu.edu.cn
Signed-off-by: Yixuan Cao <caoyixuan2019@email.szu.edu.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Merge tag 'pidfd.v5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux
Pull pidfd updates from Christian Brauner:
"Various places in the kernel have picked up pidfds.
The two most recent additions have probably been the ability to use
pidfds in bpf maps and the usage of pidfds in mm-based syscalls such
as process_mrelease() and process_madvise().
The same pattern to turn a pidfd into a struct task exists in two
places. One of those places used PIDTYPE_TGID while the other one used
PIDTYPE_PID even though it is clearly documented in all pidfd-helpers
that pidfds __currently__ only refer to thread-group leaders (subject
to change in the future if need be).
This isn't a bug per se but has the potential to be one if we allow
pidfds to refer to individual threads. If that happens we want to
audit all codepaths that make use of them to ensure they can deal with
pidfds refering to individual threads.
This adds a simple helper to turn a pidfd into a struct task making it
easy to grep for such places. Plus, it gets rid of code-duplication"
* tag 'pidfd.v5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux:
mm: use pidfd_get_task()
pid: add pidfd_get_task() helper
- Fix double-evaluation of 'pte' macro argument when using 52-bit PAs
- Fix signedness of some MTE prctl PR_* constants
- Fix kmemleak memory usage by skipping early pgtable allocations
- Fix printing of CPU feature register strings
- Remove redundant -nostdlib linker flag for vDSO binaries
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Merge tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux
Pull arm64 fixes from Will Deacon:
- Fix double-evaluation of 'pte' macro argument when using 52-bit PAs
- Fix signedness of some MTE prctl PR_* constants
- Fix kmemleak memory usage by skipping early pgtable allocations
- Fix printing of CPU feature register strings
- Remove redundant -nostdlib linker flag for vDSO binaries
* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
arm64: pgtable: make __pte_to_phys/__phys_to_pte_val inline functions
arm64: Track no early_pgtable_alloc() for kmemleak
arm64: mte: change PR_MTE_TCF_NONE back into an unsigned long
arm64: vdso: remove -nostdlib compiler flag
arm64: arm64_ftr_reg->name may not be a human-readable string
Merge more updates from Andrew Morton:
"87 patches.
Subsystems affected by this patch series: mm (pagecache and hugetlb),
procfs, misc, MAINTAINERS, lib, checkpatch, binfmt, kallsyms, ramfs,
init, codafs, nilfs2, hfs, crash_dump, signals, seq_file, fork,
sysvfs, kcov, gdb, resource, selftests, and ipc"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (87 commits)
ipc/ipc_sysctl.c: remove fallback for !CONFIG_PROC_SYSCTL
ipc: check checkpoint_restore_ns_capable() to modify C/R proc files
selftests/kselftest/runner/run_one(): allow running non-executable files
virtio-mem: disallow mapping virtio-mem memory via /dev/mem
kernel/resource: disallow access to exclusive system RAM regions
kernel/resource: clean up and optimize iomem_is_exclusive()
scripts/gdb: handle split debug for vmlinux
kcov: replace local_irq_save() with a local_lock_t
kcov: avoid enable+disable interrupts if !in_task()
kcov: allocate per-CPU memory on the relevant node
Documentation/kcov: define `ip' in the example
Documentation/kcov: include types.h in the example
sysv: use BUILD_BUG_ON instead of runtime check
kernel/fork.c: unshare(): use swap() to make code cleaner
seq_file: fix passing wrong private data
seq_file: move seq_escape() to a header
signal: remove duplicate include in signal.h
crash_dump: remove duplicate include in crash_dump.h
crash_dump: fix boolreturn.cocci warning
hfs/hfsplus: use WARN_ON for sanity check
...
virtio-mem dynamically exposes memory inside a device memory region as
system RAM to Linux, coordinating with the hypervisor which parts are
actually "plugged" and consequently usable/accessible.
On the one hand, the virtio-mem driver adds/removes whole memory blocks,
creating/removing busy IORESOURCE_SYSTEM_RAM resources, on the other
hand, it logically (un)plugs memory inside added memory blocks,
dynamically either exposing them to the buddy or hiding them from the
buddy and marking them PG_offline.
In contrast to physical devices, like a DIMM, the virtio-mem driver is
required to actually make use of any of the device-provided memory,
because it performs the handshake with the hypervisor. virtio-mem
memory cannot simply be access via /dev/mem without a driver.
There is no safe way to:
a) Access plugged memory blocks via /dev/mem, as they might contain
unplugged holes or might get silently unplugged by the virtio-mem
driver and consequently turned inaccessible.
b) Access unplugged memory blocks via /dev/mem because the virtio-mem
driver is required to make them actually accessible first.
The virtio-spec states that unplugged memory blocks MUST NOT be written,
and only selected unplugged memory blocks MAY be read. We want to make
sure, this is the case in sane environments -- where the virtio-mem driver
was loaded.
We want to make sure that in a sane environment, nobody "accidentially"
accesses unplugged memory inside the device managed region. For example,
a user might spot a memory region in /proc/iomem and try accessing it via
/dev/mem via gdb or dumping it via something else. By the time the mmap()
happens, the memory might already have been removed by the virtio-mem
driver silently: the mmap() would succeeed and user space might
accidentially access unplugged memory.
So once the driver was loaded and detected the device along the
device-managed region, we just want to disallow any access via /dev/mem to
it.
In an ideal world, we would mark the whole region as busy ("owned by a
driver") and exclude it; however, that would be wrong, as we don't really
have actual system RAM at these ranges added to Linux ("busy system RAM").
Instead, we want to mark such ranges as "not actual busy system RAM but
still soft-reserved and prepared by a driver for future use."
Let's teach iomem_is_exclusive() to reject access to any range with
"IORESOURCE_SYSTEM_RAM | IORESOURCE_EXCLUSIVE", even if not busy and even
if "iomem=relaxed" is set. Introduce EXCLUSIVE_SYSTEM_RAM to make it
easier for applicable drivers to depend on this setting in their Kconfig.
For now, there are no applicable ranges and we'll modify virtio-mem next
to properly set IORESOURCE_EXCLUSIVE on the parent resource container it
creates to contain all actual busy system RAM added via
add_memory_driver_managed().
Link: https://lkml.kernel.org/r/20210920142856.17758-3-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Cc: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Hanjun Guo <guohanjun@huawei.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
To print stack entries into a buffer, users of stackdepot, first get a
list of stack entries using stack_depot_fetch and then print this list
into a buffer using stack_trace_snprint. Provide a helper in stackdepot
for this purpose. Also change above mentioned users to use this helper.
[imran.f.khan@oracle.com: fix build error]
Link: https://lkml.kernel.org/r/20210915175321.3472770-4-imran.f.khan@oracle.com
[imran.f.khan@oracle.com: export stack_depot_snprint() to modules]
Link: https://lkml.kernel.org/r/20210916133535.3592491-4-imran.f.khan@oracle.com
Link: https://lkml.kernel.org/r/20210915014806.3206938-4-imran.f.khan@oracle.com
Signed-off-by: Imran Khan <imran.f.khan@oracle.com>
Suggested-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Jani Nikula <jani.nikula@intel.com> [i915]
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: David Airlie <airlied@linux.ie>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
To print a stack entries, users of stackdepot, first use stack_depot_fetch
to get a list of stack entries and then use stack_trace_print to print
this list. Provide a helper in stackdepot to print stack entries based on
stackdepot handle. Also change above mentioned users to use this helper.
Link: https://lkml.kernel.org/r/20210915014806.3206938-3-imran.f.khan@oracle.com
Signed-off-by: Imran Khan <imran.f.khan@oracle.com>
Suggested-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: David Airlie <airlied@linux.ie>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit 21a3c273f8 ("mm, hugetlb: add thread name and pid to
SHM_HUGETLB mlock rlimit warning") marked this as deprecated in 2012,
but it is not deleted yet.
Mike says he still sees that message in log files on occasion, so maybe we
should preserve this warning.
Also remove hugetlbfs related user_shm_unlock in ipc/shm.c and remove the
user_shm_unlock after out.
Link: https://lkml.kernel.org/r/20211103105857.25041-1-zhangyiru3@huawei.com
Signed-off-by: zhangyiru <zhangyiru3@huawei.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Liu Zixian <liuzixian4@huawei.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: wuxu.wu <wuxu.wu@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Historically (pre-2.5), the inode shrinker used to reclaim only empty
inodes and skip over those that still contained page cache. This caused
problems on highmem hosts: struct inode could put fill lowmem zones
before the cache was getting reclaimed in the highmem zones.
To address this, the inode shrinker started to strip page cache to
facilitate reclaiming lowmem. However, this comes with its own set of
problems: the shrinkers may drop actively used page cache just because
the inodes are not currently open or dirty - think working with a large
git tree. It further doesn't respect cgroup memory protection settings
and can cause priority inversions between containers.
Nowadays, the page cache also holds non-resident info for evicted cache
pages in order to detect refaults. We've come to rely heavily on this
data inside reclaim for protecting the cache workingset and driving swap
behavior. We also use it to quantify and report workload health through
psi. The latter in turn is used for fleet health monitoring, as well as
driving automated memory sizing of workloads and containers, proactive
reclaim and memory offloading schemes.
The consequences of dropping page cache prematurely is that we're seeing
subtle and not-so-subtle failures in all of the above-mentioned
scenarios, with the workload generally entering unexpected thrashing
states while losing the ability to reliably detect it.
To fix this on non-highmem systems at least, going back to rotating
inodes on the LRU isn't feasible. We've tried (commit a76cf1a474
("mm: don't reclaim inodes with many attached pages")) and failed
(commit 69056ee6a8 ("Revert "mm: don't reclaim inodes with many
attached pages"")).
The issue is mostly that shrinker pools attract pressure based on their
size, and when objects get skipped the shrinkers remember this as
deferred reclaim work. This accumulates excessive pressure on the
remaining inodes, and we can quickly eat into heavily used ones, or
dirty ones that require IO to reclaim, when there potentially is plenty
of cold, clean cache around still.
Instead, this patch keeps populated inodes off the inode LRU in the
first place - just like an open file or dirty state would. An otherwise
clean and unused inode then gets queued when the last cache entry
disappears. This solves the problem without reintroducing the reclaim
issues, and generally is a bit more scalable than having to wade through
potentially hundreds of thousands of busy inodes.
Locking is a bit tricky because the locks protecting the inode state
(i_lock) and the inode LRU (lru_list.lock) don't nest inside the
irq-safe page cache lock (i_pages.xa_lock). Page cache deletions are
serialized through i_lock, taken before the i_pages lock, to make sure
depopulated inodes are queued reliably. Additions may race with
deletions, but we'll check again in the shrinker. If additions race
with the shrinker itself, we're protected by the i_lock: if find_inode()
or iput() win, the shrinker will bail on the elevated i_count or
I_REFERENCED; if the shrinker wins and goes ahead with the inode, it
will set I_FREEING and inhibit further igets(), which will cause the
other side to create a new instance of the inode instead.
Link: https://lkml.kernel.org/r/20210614211904.14420-4-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Roman Gushchin <guro@fb.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Dave Chinner <david@fromorbit.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
After switched page size from 64KB to 4KB on several arm64 servers here,
kmemleak starts to run out of early memory pool due to a huge number of
those early_pgtable_alloc() calls:
kmemleak_alloc_phys()
memblock_alloc_range_nid()
memblock_phys_alloc_range()
early_pgtable_alloc()
init_pmd()
alloc_init_pud()
__create_pgd_mapping()
__map_memblock()
paging_init()
setup_arch()
start_kernel()
Increased the default value of DEBUG_KMEMLEAK_MEM_POOL_SIZE by 4 times
won't be enough for a server with 200GB+ memory. There isn't much
interesting to check memory leaks for those early page tables and those
early memory mappings should not reference to other memory. Hence, no
kmemleak false positives, and we can safely skip tracking those early
allocations from kmemleak like we did in the commit fed84c7852
("mm/memblock.c: skip kmemleak for kasan_init()") without needing to
introduce complications to automatically scale the value depends on the
runtime memory size etc. After the patch, the default value of
DEBUG_KMEMLEAK_MEM_POOL_SIZE becomes sufficient again.
Signed-off-by: Qian Cai <quic_qiancai@quicinc.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Mike Rapoport <rppt@linux.ibm.com>
Link: https://lore.kernel.org/r/20211105150509.7826-1-quic_qiancai@quicinc.com
Signed-off-by: Will Deacon <will@kernel.org>
Merge misc updates from Andrew Morton:
"257 patches.
Subsystems affected by this patch series: scripts, ocfs2, vfs, and
mm (slab-generic, slab, slub, kconfig, dax, kasan, debug, pagecache,
gup, swap, memcg, pagemap, mprotect, mremap, iomap, tracing, vmalloc,
pagealloc, memory-failure, hugetlb, userfaultfd, vmscan, tools,
memblock, oom-kill, hugetlbfs, migration, thp, readahead, nommu, ksm,
vmstat, madvise, memory-hotplug, rmap, zsmalloc, highmem, zram,
cleanups, kfence, and damon)"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (257 commits)
mm/damon: remove return value from before_terminate callback
mm/damon: fix a few spelling mistakes in comments and a pr_debug message
mm/damon: simplify stop mechanism
Docs/admin-guide/mm/pagemap: wordsmith page flags descriptions
Docs/admin-guide/mm/damon/start: simplify the content
Docs/admin-guide/mm/damon/start: fix a wrong link
Docs/admin-guide/mm/damon/start: fix wrong example commands
mm/damon/dbgfs: add adaptive_targets list check before enable monitor_on
mm/damon: remove unnecessary variable initialization
Documentation/admin-guide/mm/damon: add a document for DAMON_RECLAIM
mm/damon: introduce DAMON-based Reclamation (DAMON_RECLAIM)
selftests/damon: support watermarks
mm/damon/dbgfs: support watermarks
mm/damon/schemes: activate schemes based on a watermarks mechanism
tools/selftests/damon: update for regions prioritization of schemes
mm/damon/dbgfs: support prioritization weights
mm/damon/vaddr,paddr: support pageout prioritization
mm/damon/schemes: prioritize regions within the quotas
mm/damon/selftests: support schemes quotas
mm/damon/dbgfs: support quotas of schemes
...
Since the return value of 'before_terminate' callback is never used, we
make it have no return value.
Link: https://lkml.kernel.org/r/20211029005023.8895-1-changbin.du@gmail.com
Signed-off-by: Changbin Du <changbin.du@gmail.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There are a few spelling mistakes in the code. Fix these.
Link: https://lkml.kernel.org/r/20211028184157.614544-1-colin.i.king@gmail.com
Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
A kernel thread can exit gracefully with kthread_stop(). So we don't
need a new flag 'kdamond_stop'. And to make sure the task struct is not
freed when accessing it, get reference to it before termination.
Link: https://lkml.kernel.org/r/20211027130517.4404-1-changbin.du@gmail.com
Signed-off-by: Changbin Du <changbin.du@gmail.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When the ctx->adaptive_targets list is empty, I did some test on
monitor_on interface like this.
# cat /sys/kernel/debug/damon/target_ids
#
# echo on > /sys/kernel/debug/damon/monitor_on
# damon: kdamond (5390) starts
Though the ctx->adaptive_targets list is empty, but the kthread_run
still be called, and the kdamond.x thread still be created, this is
meaningless.
So there adds a judgment in 'dbgfs_monitor_on_write', if the
ctx->adaptive_targets list is empty, return -EINVAL.
Link: https://lkml.kernel.org/r/0a60a6e8ec9d71989e0848a4dc3311996ca3b5d4.1634720326.git.xhao@linux.alibaba.com
Signed-off-by: Xin Hao <xhao@linux.alibaba.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This implements a new kernel subsystem that finds cold memory regions
using DAMON and reclaims those immediately. It is intended to be used
as proactive lightweigh reclamation logic for light memory pressure.
For heavy memory pressure, it could be inactivated and fall back to the
traditional page-scanning based reclamation.
It's implemented on top of DAMON framework to use the DAMON-based
Operation Schemes (DAMOS) feature. It utilizes all the DAMOS features
including speed limit, prioritization, and watermarks.
It could be enabled and tuned in boot time via the kernel boot
parameter, and in run time via its module parameters
('/sys/module/damon_reclaim/parameters/') interface.
[yangyingliang@huawei.com: fix error return code in damon_reclaim_turn()]
Link: https://lkml.kernel.org/r/20211025124500.2758060-1-yangyingliang@huawei.com
Link: https://lkml.kernel.org/r/20211019150731.16699-15-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Cc: Amit Shah <amit@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: David Woodhouse <dwmw@amazon.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Leonard Foerster <foersleo@amazon.de>
Cc: Marco Elver <elver@google.com>
Cc: Markus Boehme <markubo@amazon.de>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This updates DAMON debugfs interface to support the watermarks based
schemes activation. For this, now 'schemes' file receives five more
values.
Link: https://lkml.kernel.org/r/20211019150731.16699-13-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Amit Shah <amit@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: David Woodhouse <dwmw@amazon.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Leonard Foerster <foersleo@amazon.de>
Cc: Marco Elver <elver@google.com>
Cc: Markus Boehme <markubo@amazon.de>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
DAMON-based operation schemes need to be manually turned on and off. In
some use cases, however, the condition for turning a scheme on and off
would depend on the system's situation. For example, schemes for
proactive pages reclamation would need to be turned on when some memory
pressure is detected, and turned off when the system has enough free
memory.
For easier control of schemes activation based on the system situation,
this introduces a watermarks-based mechanism. The client can describe
the watermark metric (e.g., amount of free memory in the system),
watermark check interval, and three watermarks, namely high, mid, and
low. If the scheme is deactivated, it only gets the metric and compare
that to the three watermarks for every check interval. If the metric is
higher than the high watermark, the scheme is deactivated. If the
metric is between the mid watermark and the low watermark, the scheme is
activated. If the metric is lower than the low watermark, the scheme is
deactivated again. This is to allow users fall back to traditional
page-granularity mechanisms.
Link: https://lkml.kernel.org/r/20211019150731.16699-12-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Amit Shah <amit@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: David Woodhouse <dwmw@amazon.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Leonard Foerster <foersleo@amazon.de>
Cc: Marco Elver <elver@google.com>
Cc: Markus Boehme <markubo@amazon.de>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This allows DAMON debugfs interface users set the prioritization weights
by putting three more numbers to the 'schemes' file.
Link: https://lkml.kernel.org/r/20211019150731.16699-10-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Amit Shah <amit@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: David Woodhouse <dwmw@amazon.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Leonard Foerster <foersleo@amazon.de>
Cc: Marco Elver <elver@google.com>
Cc: Markus Boehme <markubo@amazon.de>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This makes the default monitoring primitives for virtual address spaces
and the physical address sapce to support memory regions prioritization
for 'PAGEOUT' DAMOS action. It calculates hotness of each region as
weighted sum of 'nr_accesses' and 'age' of the region and get the
priority score as reverse of the hotness, so that cold regions can be
paged out first.
Link: https://lkml.kernel.org/r/20211019150731.16699-9-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Amit Shah <amit@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: David Woodhouse <dwmw@amazon.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Leonard Foerster <foersleo@amazon.de>
Cc: Marco Elver <elver@google.com>
Cc: Markus Boehme <markubo@amazon.de>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This makes DAMON apply schemes to regions having higher priority first,
if it cannot apply schemes to all regions due to the quotas.
The prioritization function should be implemented in the monitoring
primitives. Those would commonly calculate the priority of the region
using attributes of regions, namely 'size', 'nr_accesses', and 'age'.
For example, some primitive would calculate the priority of each region
using a weighted sum of 'nr_accesses' and 'age' of the region.
The optimal weights would depend on give environments, so this makes
those customizable. Nevertheless, the score calculation functions are
only encouraged to respect the weights, not mandated.
Link: https://lkml.kernel.org/r/20211019150731.16699-8-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Amit Shah <amit@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: David Woodhouse <dwmw@amazon.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Leonard Foerster <foersleo@amazon.de>
Cc: Marco Elver <elver@google.com>
Cc: Markus Boehme <markubo@amazon.de>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This makes the debugfs interface of DAMON support the scheme quotas by
chaning the format of the input for the schemes file.
Link: https://lkml.kernel.org/r/20211019150731.16699-6-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Amit Shah <amit@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: David Woodhouse <dwmw@amazon.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Leonard Foerster <foersleo@amazon.de>
Cc: Marco Elver <elver@google.com>
Cc: Markus Boehme <markubo@amazon.de>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The size quota feature of DAMOS is useful for IO resource-critical
systems, but not so intuitive for CPU time-critical systems. Systems
using zram or zswap-like swap device would be examples.
To provide another intuitive ways for such systems, this implements
time-based quota for DAMON-based Operation Schemes. If the quota is
set, DAMOS tries to use only up to the user-defined quota of CPU time
within a given time window.
Link: https://lkml.kernel.org/r/20211019150731.16699-5-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Amit Shah <amit@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: David Woodhouse <dwmw@amazon.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Leonard Foerster <foersleo@amazon.de>
Cc: Marco Elver <elver@google.com>
Cc: Markus Boehme <markubo@amazon.de>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
If DAMOS has stopped applying action in the middle of a group of memory
regions due to its size quota, it starts the work again from the
beginning of the address space in the next charge window. If there is a
huge memory region at the beginning of the address space and it fulfills
the scheme's target data access pattern always, the action will applied
to only the region.
This mitigates the case by skipping memory regions that charged in
current charge window at the beginning of next charge window.
Link: https://lkml.kernel.org/r/20211019150731.16699-4-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Amit Shah <amit@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: David Woodhouse <dwmw@amazon.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Leonard Foerster <foersleo@amazon.de>
Cc: Marco Elver <elver@google.com>
Cc: Markus Boehme <markubo@amazon.de>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There could be arbitrarily large memory regions fulfilling the target
data access pattern of a DAMON-based operation scheme. In the case,
applying the action of the scheme could incur too high overhead. To
provide an intuitive way for avoiding it, this implements a feature
called size quota. If the quota is set, DAMON tries to apply the action
only up to the given amount of memory regions within a given time
window.
Link: https://lkml.kernel.org/r/20211019150731.16699-3-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Amit Shah <amit@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: David Woodhouse <dwmw@amazon.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Leonard Foerster <foersleo@amazon.de>
Cc: Marco Elver <elver@google.com>
Cc: Markus Boehme <markubo@amazon.de>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Introduction
============
This patchset 1) makes the engine for general data access
pattern-oriented memory management (DAMOS) be more useful for production
environments, and 2) implements a static kernel module for lightweight
proactive reclamation using the engine.
Proactive Reclamation
---------------------
On general memory over-committed systems, proactively reclaiming cold
pages helps saving memory and reducing latency spikes that incurred by
the direct reclaim or the CPU consumption of kswapd, while incurring
only minimal performance degradation[2].
A Free Pages Reporting[8] based memory over-commit virtualization system
would be one more specific use case. In the system, the guest VMs
reports their free memory to host, and the host reallocates the reported
memory to other guests. As a result, the system's memory utilization
can be maximized. However, the guests could be not so memory-frugal,
because some kernel subsystems and user-space applications are designed
to use as much memory as available. Then, guests would report only
small amount of free memory to host, results in poor memory utilization.
Running the proactive reclamation in such guests could help mitigating
this problem.
Google has also implemented this idea and using it in their data center.
They further proposed upstreaming it in LSFMM'19, and "the general
consensus was that, while this sort of proactive reclaim would be useful
for a number of users, the cost of this particular solution was too high
to consider merging it upstream"[3]. The cost mainly comes from the
coldness tracking. Roughly speaking, the implementation periodically
scans the 'Accessed' bit of each page. For the reason, the overhead
linearly increases as the size of the memory and the scanning frequency
grows. As a result, Google is known to dedicating one CPU for the work.
That's a reasonable option to someone like Google, but it wouldn't be so
to some others.
DAMON and DAMOS: An engine for data access pattern-oriented memory management
-----------------------------------------------------------------------------
DAMON[4] is a framework for general data access monitoring. Its
adaptive monitoring overhead control feature minimizes its monitoring
overhead. It also let the upper-bound of the overhead be configurable
by clients, regardless of the size of the monitoring target memory.
While monitoring 70 GiB memory of a production system every 5
milliseconds, it consumes less than 1% single CPU time. For this, it
could sacrify some of the quality of the monitoring results.
Nevertheless, the lower-bound of the quality is configurable, and it
uses a best-effort algorithm for better quality. Our test results[5]
show the quality is practical enough. From the production system
monitoring, we were able to find a 4 KiB region in the 70 GiB memory
that shows highest access frequency.
We normally don't monitor the data access pattern just for fun but to
improve something like memory management. Proactive reclamation is one
such usage. For such general cases, DAMON provides a feature called
DAMon-based Operation Schemes (DAMOS)[6]. It makes DAMON an engine for
general data access pattern oriented memory management. Using this,
clients can ask DAMON to find memory regions of specific data access
pattern and apply some memory management action (e.g., page out, move to
head of the LRU list, use huge page, ...). We call the request
'scheme'.
Proactive Reclamation on top of DAMON/DAMOS
-------------------------------------------
Therefore, by using DAMON for the cold pages detection, the proactive
reclamation's monitoring overhead issue can be solved. Actually, we
previously implemented a version of proactive reclamation using DAMOS
and achieved noticeable improvements with our evaluation setup[5].
Nevertheless, it more for a proof-of-concept, rather than production
uses. It supports only virtual address spaces of processes, and require
additional tuning efforts for given workloads and the hardware. For the
tuning, we introduced a simple auto-tuning user space tool[8]. Google
is also known to using a ML-based similar approach for their fleets[2].
But, making it just works with intuitive knobs in the kernel would be
helpful for general users.
To this end, this patchset improves DAMOS to be ready for such
production usages, and implements another version of the proactive
reclamation, namely DAMON_RECLAIM, on top of it.
DAMOS Improvements: Aggressiveness Control, Prioritization, and Watermarks
--------------------------------------------------------------------------
First of all, the current version of DAMOS supports only virtual address
spaces. This patchset makes it supports the physical address space for
the page out action.
Next major problem of the current version of DAMOS is the lack of the
aggressiveness control, which can results in arbitrary overhead. For
example, if huge memory regions having the data access pattern of
interest are found, applying the requested action to all of the regions
could incur significant overhead. It can be controlled by tuning the
target data access pattern with manual or automated approaches[2,7].
But, some people would prefer the kernel to just work with only
intuitive tuning or default values.
For such cases, this patchset implements a safeguard, namely time/size
quota. Using this, the clients can specify up to how much time can be
used for applying the action, and/or up to how much memory regions the
action can be applied within a user-specified time duration. A followup
question is, to which memory regions should the action applied within
the limits? We implement a simple regions prioritization mechanism for
each action and make DAMOS to apply the action to high priority regions
first. It also allows clients tune the prioritization mechanism to use
different weights for size, access frequency, and age of memory regions.
This means we could use not only LRU but also LFU or some fancy
algorithms like CAR[9] with lightweight overhead.
Though DAMON is lightweight, someone would want to remove even the cold
pages monitoring overhead when it is unnecessary. Currently, it should
manually turned on and off by clients, but some clients would simply
want to turn it on and off based on some metrics like free memory ratio
or memory fragmentation. For such cases, this patchset implements a
watermarks-based automatic activation feature. It allows the clients
configure the metric of their interest, and three watermarks of the
metric. If the metric is higher than the high watermark or lower than
the low watermark, the scheme is deactivated. If the metric is lower
than the mid watermark but higher than the low watermark, the scheme is
activated.
DAMON-based Reclaim
-------------------
Using the improved version of DAMOS, this patchset implements a static
kernel module called 'damon_reclaim'. It finds memory regions that
didn't accessed for specific time duration and page out. Consuming too
much CPU for the paging out operations, or doing pageout too frequently
can be critical for systems configuring their swap devices with
software-defined in-memory block devices like zram/zswap or total number
of writes limited devices like SSDs, respectively. To avoid the
problems, the time/size quotas can be configured. Under the quotas, it
pages out memory regions that didn't accessed longer first. Also, to
remove the monitoring overhead under peaceful situation, and to fall
back to the LRU-list based page granularity reclamation when it doesn't
make progress, the three watermarks based activation mechanism is used,
with the free memory ratio as the watermark metric.
For convenient configurations, it provides several module parameters.
Using these, sysadmins can enable/disable it, and tune its parameters
including the coldness identification time threshold, the time/size
quotas and the three watermarks.
Evaluation
==========
In short, DAMON_RECLAIM with 50ms/s time quota and regions
prioritization on v5.15-rc5 Linux kernel with ZRAM swap device achieves
38.58% memory saving with only 1.94% runtime overhead. For this,
DAMON_RECLAIM consumes only 4.97% of single CPU time.
Setup
-----
We evaluate DAMON_RECLAIM to show how each of the DAMOS improvements
make effect. For this, we measure DAMON_RECLAIM's CPU consumption,
entire system memory footprint, total number of major page faults, and
runtime of 24 realistic workloads in PARSEC3 and SPLASH-2X benchmark
suites on my QEMU/KVM based virtual machine. The virtual machine runs
on an i3.metal AWS instance, has 130GiB memory, and runs a linux kernel
built on latest -mm tree[1] plus this patchset. It also utilizes a 4
GiB ZRAM swap device. We repeats the measurement 5 times and use
averages.
[1] https://github.com/hnaz/linux-mm/tree/v5.15-rc5-mmots-2021-10-13-19-55
Detailed Results
----------------
The results are summarized in the below table.
With coldness identification threshold of 5 seconds, DAMON_RECLAIM
without the time quota-based speed limit achieves 47.21% memory saving,
but incur 4.59% runtime slowdown to the workloads on average. For this,
DAMON_RECLAIM consumes about 11.28% single CPU time.
Applying time quotas of 200ms/s, 50ms/s, and 10ms/s without the regions
prioritization reduces the slowdown to 4.89%, 2.65%, and 1.5%,
respectively. Time quota of 200ms/s (20%) makes no real change compared
to the quota unapplied version, because the quota unapplied version
consumes only 11.28% CPU time. DAMON_RECLAIM's CPU utilization also
similarly reduced: 11.24%, 5.51%, and 2.01% of single CPU time. That
is, the overhead is proportional to the speed limit. Nevertheless, it
also reduces the memory saving because it becomes less aggressive. In
detail, the three variants show 48.76%, 37.83%, and 7.85% memory saving,
respectively.
Applying the regions prioritization (page out regions that not accessed
longer first within the time quota) further reduces the performance
degradation. Runtime slowdowns and total number of major page faults
increase has been 4.89%/218,690% -> 4.39%/166,136% (200ms/s),
2.65%/111,886% -> 1.94%/59,053% (50ms/s), and 1.5%/34,973.40% ->
2.08%/8,781.75% (10ms/s). The runtime under 10ms/s time quota has
increased with prioritization, but apparently that's under the margin of
error.
time quota prioritization memory_saving cpu_util slowdown pgmajfaults overhead
N N 47.21% 11.28% 4.59% 194,802%
200ms/s N 48.76% 11.24% 4.89% 218,690%
50ms/s N 37.83% 5.51% 2.65% 111,886%
10ms/s N 7.85% 2.01% 1.5% 34,793.40%
200ms/s Y 50.08% 10.38% 4.39% 166,136%
50ms/s Y 38.58% 4.97% 1.94% 59,053%
10ms/s Y 3.63% 1.73% 2.08% 8,781.75%
Baseline and Complete Git Trees
===============================
The patches are based on the latest -mm tree
(v5.15-rc5-mmots-2021-10-13-19-55). You can also clone the complete git tree
from:
$ git clone git://github.com/sjp38/linux -b damon_reclaim/patches/v1
The web is also available:
https://git.kernel.org/pub/scm/linux/kernel/git/sj/linux.git/tag/?h=damon_reclaim/patches/v1
Sequence Of Patches
===================
The first patch makes DAMOS support the physical address space for the
page out action. Following five patches (patches 2-6) implement the
time/size quotas. Next four patches (patches 7-10) implement the memory
regions prioritization within the limit. Then, three following patches
(patches 11-13) implement the watermarks-based schemes activation.
Finally, the last two patches (patches 14-15) implement and document the
DAMON-based reclamation using the advanced DAMOS.
[1] https://www.kernel.org/doc/html/v5.15-rc1/vm/damon/index.html
[2] https://research.google/pubs/pub48551/
[3] https://lwn.net/Articles/787611/
[4] https://damonitor.github.io
[5] https://damonitor.github.io/doc/html/latest/vm/damon/eval.html
[6] https://lore.kernel.org/linux-mm/20211001125604.29660-1-sj@kernel.org/
[7] https://github.com/awslabs/damoos
[8] https://www.kernel.org/doc/html/latest/vm/free_page_reporting.html
[9] https://www.usenix.org/conference/fast-04/car-clock-adaptive-replacement
This patch (of 15):
This makes the DAMON primitives for physical address space support the
pageout action for DAMON-based Operation Schemes. With this commit,
hence, users can easily implement system-level data access-aware
reclamations using DAMOS.
[sj@kernel.org: fix missing-prototype build warning]
Link: https://lkml.kernel.org/r/20211025064220.13904-1-sj@kernel.org
Link: https://lkml.kernel.org/r/20211019150731.16699-1-sj@kernel.org
Link: https://lkml.kernel.org/r/20211019150731.16699-2-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Amit Shah <amit@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Woodhouse <dwmw@amazon.com>
Cc: Marco Elver <elver@google.com>
Cc: Leonard Foerster <foersleo@amazon.de>
Cc: Greg Thelen <gthelen@google.com>
Cc: Markus Boehme <markubo@amazon.de>
Cc: David Rientjes <rientjes@google.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In some functions, it's unnecessary to declare 'err' and 'ret' variables
at the same time. This patch mainly to simplify the issue of such
declarations by reusing one variable.
Link: https://lkml.kernel.org/r/20211014073014.35754-1-sj@kernel.org
Signed-off-by: Rongwei Wang <rongwei.wang@linux.alibaba.com>
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The only usage of these structs is to pass their addresses to
walk_page_range(), which takes a pointer to const mm_walk_ops as
argument. Make them const to allow the compiler to put them in
read-only memory.
Link: https://lkml.kernel.org/r/20211014075042.17174-2-rikard.falkeborn@gmail.com
Signed-off-by: Rikard Falkeborn <rikard.falkeborn@gmail.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This makes the 'damon-dbgfs' to support the physical memory monitoring,
in addition to the virtual memory monitoring.
Users can do the physical memory monitoring by writing a special
keyword, 'paddr' to the 'target_ids' debugfs file. Then, DAMON will
check the special keyword and configure the monitoring context to run
with the primitives for the physical address space.
Unlike the virtual memory monitoring, the monitoring target region will
not be automatically set. Therefore, users should also set the
monitoring target address region using the 'init_regions' debugfs file.
Also, note that the physical memory monitoring will not automatically
terminated. The user should explicitly turn off the monitoring by
writing 'off' to the 'monitor_on' debugfs file.
Link: https://lkml.kernel.org/r/20211012205711.29216-7-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Amit Shah <amit@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Brendan Higgins <brendanhiggins@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rienjes <rientjes@google.com>
Cc: David Woodhouse <dwmw@amazon.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Leonard Foerster <foersleo@amazon.de>
Cc: Marco Elver <elver@google.com>
Cc: Markus Boehme <markubo@amazon.de>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This implements the monitoring primitives for the physical memory
address space. Internally, it uses the PTE Accessed bit, similar to
that of the virtual address spaces monitoring primitives. It supports
only user memory pages, as idle pages tracking does. If the monitoring
target physical memory address range contains non-user memory pages,
access check of the pages will do nothing but simply treat the pages as
not accessed.
Link: https://lkml.kernel.org/r/20211012205711.29216-6-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Amit Shah <amit@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Brendan Higgins <brendanhiggins@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rienjes <rientjes@google.com>
Cc: David Woodhouse <dwmw@amazon.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Leonard Foerster <foersleo@amazon.de>
Cc: Marco Elver <elver@google.com>
Cc: Markus Boehme <markubo@amazon.de>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This moves functions in the default virtual address spaces monitoring
primitives that commonly usable from other address spaces like physical
address space into a header file. Those will be reused by the physical
address space monitoring primitives which will be implemented by the
following commit.
[sj@kernel.org: include 'highmem.h' to fix a build failure]
Link: https://lkml.kernel.org/r/20211014110848.5204-1-sj@kernel.org
Link: https://lkml.kernel.org/r/20211012205711.29216-5-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Amit Shah <amit@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Brendan Higgins <brendanhiggins@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rienjes <rientjes@google.com>
Cc: David Woodhouse <dwmw@amazon.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Leonard Foerster <foersleo@amazon.de>
Cc: Marco Elver <elver@google.com>
Cc: Markus Boehme <markubo@amazon.de>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This adds another test case for the new feature, 'init_regions'.
Link: https://lkml.kernel.org/r/20211012205711.29216-3-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Reviewed-by: Brendan Higgins <brendanhiggins@google.com>
Cc: Amit Shah <amit@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rienjes <rientjes@google.com>
Cc: David Woodhouse <dwmw@amazon.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Leonard Foerster <foersleo@amazon.de>
Cc: Marco Elver <elver@google.com>
Cc: Markus Boehme <markubo@amazon.de>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "DAMON: Support Physical Memory Address Space Monitoring:.
DAMON currently supports only virtual address spaces monitoring. It can
be easily extended for various use cases and address spaces by
configuring its monitoring primitives layer to use appropriate
primitives implementations, though. This patchset implements monitoring
primitives for the physical address space monitoring using the
structure.
The first 3 patches allow the user space users manually set the
monitoring regions. The 1st patch implements the feature in the
'damon-dbgfs'. Then, patches for adding a unit tests (the 2nd patch)
and updating the documentation (the 3rd patch) follow.
Following 4 patches implement the physical address space monitoring
primitives. The 4th patch makes some primitive functions for the
virtual address spaces primitives reusable. The 5th patch implements
the physical address space monitoring primitives. The 6th patch links
the primitives to the 'damon-dbgfs'. Finally, 7th patch documents this
new features.
This patch (of 7):
Some 'damon-dbgfs' users would want to monitor only a part of the entire
virtual memory address space. The program interface users in the kernel
space could use '->before_start()' callback or set the regions inside
the context struct as they want, but 'damon-dbgfs' users cannot.
For that reason, this introduces a new debugfs file called
'init_region'. 'damon-dbgfs' users can specify which initial monitoring
target address regions they want by writing special input to the file.
The input should describe each region in each line in the below form:
<pid> <start address> <end address>
Note that the regions will be updated to cover entire memory mapped
regions after a 'regions update interval' is passed. If you want the
regions to not be updated after the initial setting, you could set the
interval as a very long time, say, a few decades.
Link: https://lkml.kernel.org/r/20211012205711.29216-1-sj@kernel.org
Link: https://lkml.kernel.org/r/20211012205711.29216-2-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Amit Shah <amit@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Woodhouse <dwmw@amazon.com>
Cc: Marco Elver <elver@google.com>
Cc: Leonard Foerster <foersleo@amazon.de>
Cc: Greg Thelen <gthelen@google.com>
Cc: Markus Boehme <markubo@amazon.de>
Cc: David Rienjes <rientjes@google.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
To tune the DAMON-based operation schemes, knowing how many and how
large regions are affected by each of the schemes will be helful. Those
stats could be used for not only the tuning, but also monitoring of the
working set size and the number of regions, if the scheme does not
change the program behavior too much.
For the reason, this implements the statistics for the schemes. The
total number and size of the regions that each scheme is applied are
exported to users via '->stat_count' and '->stat_sz' of 'struct damos'.
Admins can also check the number by reading 'schemes' debugfs file. The
last two integers now represents the stats. To allow collecting the
stats without changing the program behavior, this also adds new scheme
action, 'DAMOS_STAT'. Note that 'DAMOS_STAT' is not only making no
memory operation actions, but also does not reset the age of regions.
Link: https://lkml.kernel.org/r/20211001125604.29660-6-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Amit Shah <amit@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rienjes <rientjes@google.com>
Cc: David Woodhouse <dwmw@amazon.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Leonard Foerster <foersleo@amazon.de>
Cc: Marco Elver <elver@google.com>
Cc: Markus Boehme <markubo@amazon.de>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This makes 'damon-dbgfs' to support the data access monitoring oriented
memory management schemes. Users can read and update the schemes using
``<debugfs>/damon/schemes`` file. The format is::
<min/max size> <min/max access frequency> <min/max age> <action>
Link: https://lkml.kernel.org/r/20211001125604.29660-5-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Amit Shah <amit@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rienjes <rientjes@google.com>
Cc: David Woodhouse <dwmw@amazon.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Leonard Foerster <foersleo@amazon.de>
Cc: Marco Elver <elver@google.com>
Cc: Markus Boehme <markubo@amazon.de>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This makes DAMON's default primitives for virtual address spaces to
support DAMON-based Operation Schemes (DAMOS) by implementing actions
application functions and registering it to the monitoring context. The
implementation simply links 'madvise()' for related DAMOS actions. That
is, 'madvise(MADV_WILLNEED)' is called for 'WILLNEED' DAMOS action and
similar for other actions ('COLD', 'PAGEOUT', 'HUGEPAGE', 'NOHUGEPAGE').
So, the kernel space DAMON users can now use the DAMON-based
optimizations with only small amount of code.
Link: https://lkml.kernel.org/r/20211001125604.29660-4-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Amit Shah <amit@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rienjes <rientjes@google.com>
Cc: David Woodhouse <dwmw@amazon.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Leonard Foerster <foersleo@amazon.de>
Cc: Marco Elver <elver@google.com>
Cc: Markus Boehme <markubo@amazon.de>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In many cases, users might use DAMON for simple data access aware memory
management optimizations such as applying an operation scheme to a
memory region of a specific size having a specific access frequency for
a specific time. For example, "page out a memory region larger than 100
MiB but having a low access frequency more than 10 minutes", or "Use THP
for a memory region larger than 2 MiB having a high access frequency for
more than 2 seconds".
Most simple form of the solution would be doing offline data access
pattern profiling using DAMON and modifying the application source code
or system configuration based on the profiling results. Or, developing
a daemon constructed with two modules (one for access monitoring and the
other for applying memory management actions via mlock(), madvise(),
sysctl, etc) is imaginable.
To avoid users spending their time for implementation of such simple
data access monitoring-based operation schemes, this makes DAMON to
handle such schemes directly. With this change, users can simply
specify their desired schemes to DAMON. Then, DAMON will automatically
apply the schemes to the user-specified target processes.
Each of the schemes is composed with conditions for filtering of the
target memory regions and desired memory management action for the
target. Specifically, the format is::
<min/max size> <min/max access frequency> <min/max age> <action>
The filtering conditions are size of memory region, number of accesses
to the region monitored by DAMON, and the age of the region. The age of
region is incremented periodically but reset when its addresses or
access frequency has significantly changed or the action of a scheme was
applied. For the action, current implementation supports a few of
madvise()-like hints, ``WILLNEED``, ``COLD``, ``PAGEOUT``, ``HUGEPAGE``,
and ``NOHUGEPAGE``.
Because DAMON supports various address spaces and application of the
actions to a monitoring target region is dependent to the type of the
target address space, the application code should be implemented by each
primitives and registered to the framework. Note that this only
implements the framework part. Following commit will implement the
action applications for virtual address spaces primitives.
Link: https://lkml.kernel.org/r/20211001125604.29660-3-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Amit Shah <amit@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rienjes <rientjes@google.com>
Cc: David Woodhouse <dwmw@amazon.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Leonard Foerster <foersleo@amazon.de>
Cc: Marco Elver <elver@google.com>
Cc: Markus Boehme <markubo@amazon.de>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "Implement Data Access Monitoring-based Memory Operation Schemes".
Introduction
============
DAMON[1] can be used as a primitive for data access aware memory
management optimizations. For that, users who want such optimizations
should run DAMON, read the monitoring results, analyze it, plan a new
memory management scheme, and apply the new scheme by themselves. Such
efforts will be inevitable for some complicated optimizations.
However, in many other cases, the users would simply want the system to
apply a memory management action to a memory region of a specific size
having a specific access frequency for a specific time. For example,
"page out a memory region larger than 100 MiB keeping only rare accesses
more than 2 minutes", or "Do not use THP for a memory region larger than
2 MiB rarely accessed for more than 1 seconds".
To make the works easier and non-redundant, this patchset implements a
new feature of DAMON, which is called Data Access Monitoring-based
Operation Schemes (DAMOS). Using the feature, users can describe the
normal schemes in a simple way and ask DAMON to execute those on its
own.
[1] https://damonitor.github.io
Evaluations
===========
DAMOS is accurate and useful for memory management optimizations. An
experimental DAMON-based operation scheme for THP, 'ethp', removes
76.15% of THP memory overheads while preserving 51.25% of THP speedup.
Another experimental DAMON-based 'proactive reclamation' implementation,
'prcl', reduces 93.38% of residential sets and 23.63% of system memory
footprint while incurring only 1.22% runtime overhead in the best case
(parsec3/freqmine).
NOTE that the experimental THP optimization and proactive reclamation
are not for production but only for proof of concepts.
Please refer to the showcase web site's evaluation document[1] for
detailed evaluation setup and results.
[1] https://damonitor.github.io/doc/html/v34/vm/damon/eval.html
Long-term Support Trees
-----------------------
For people who want to test DAMON but using LTS kernels, there are
another couple of trees based on two latest LTS kernels respectively and
containing the 'damon/master' backports.
- For v5.4.y: https://git.kernel.org/sj/h/damon/for-v5.4.y
- For v5.10.y: https://git.kernel.org/sj/h/damon/for-v5.10.y
Sequence Of Patches
===================
The 1st patch accounts age of each region. The 2nd patch implements the
core of the DAMON-based operation schemes feature. The 3rd patch makes
the default monitoring primitives for virtual address spaces to support
the schemes. From this point, the kernel space users can use DAMOS.
The 4th patch exports the feature to the user space via the debugfs
interface. The 5th patch implements schemes statistics feature for
easier tuning of the schemes and runtime access pattern analysis, and
the 6th patch adds selftests for these changes. Finally, the 7th patch
documents this new feature.
This patch (of 7):
DAMON can be used for data access pattern aware memory management
optimizations. For that, users should run DAMON, read the monitoring
results, analyze it, plan a new memory management scheme, and apply the
new scheme by themselves. It would not be too hard, but still require
some level of effort. For complicated cases, this effort is inevitable.
That said, in many cases, users would simply want to apply an actions to
a memory region of a specific size having a specific access frequency
for a specific time. For example, "page out a memory region larger than
100 MiB but having a low access frequency more than 10 minutes", or "Use
THP for a memory region larger than 2 MiB having a high access frequency
for more than 2 seconds".
For such optimizations, users will need to first account the age of each
region themselves. To reduce such efforts, this implements a simple age
account of each region in DAMON. For each aggregation step, DAMON
compares the access frequency with that from last aggregation and reset
the age of the region if the change is significant. Else, the age is
incremented. Also, in case of the merge of regions, the region
size-weighted average of the ages is set as the age of merged new
region.
Link: https://lkml.kernel.org/r/20211001125604.29660-1-sj@kernel.org
Link: https://lkml.kernel.org/r/20211001125604.29660-2-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Amit Shah <amit@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Woodhouse <dwmw@amazon.com>
Cc: Marco Elver <elver@google.com>
Cc: Leonard Foerster <foersleo@amazon.de>
Cc: Greg Thelen <gthelen@google.com>
Cc: Markus Boehme <markubo@amazon.de>
Cc: David Rienjes <rientjes@google.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently a plain integer is being used to nullify the pointer
ctx->kdamond. Use NULL instead. Cleans up sparse warning:
mm/damon/core.c:317:40: warning: Using plain integer as NULL pointer
Link: https://lkml.kernel.org/r/20210925215908.181226-1-colin.king@canonical.com
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Just get the pid by 'current->pid'. Meanwhile, to be symmetrical make
the 'starts' and 'finishes' logs both use debug level.
Link: https://lkml.kernel.org/r/20210927232432.17750-1-changbin.du@gmail.com
Signed-off-by: Changbin Du <changbin.du@gmail.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Just return from the kthread function.
Link: https://lkml.kernel.org/r/20210927232421.17694-1-changbin.du@gmail.com
Signed-off-by: Changbin Du <changbin.du@gmail.com>
Cc: SeongJae Park <sjpark@amazon.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Logging of kdamond startup is using 'pr_info()' unnecessarily. This
makes it to use 'pr_debug()' instead.
Link: https://lkml.kernel.org/r/20210917123958.3819-6-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: SeongJae Park <sjpark@amazon.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Correct a singular versus plural grammar mistake in the help text for
the DAMON_VADDR config symbol.
Link: https://lkml.kernel.org/r/20210914073451.3883834-1-geert@linux-m68k.org
Fixes: 3f49584b26 ("mm/damon: implement primitives for the virtual memory address spaces")
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Reviewed-by: SeongJae Park <sjpark@amazon.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Regardless of KFENCE mode (CONFIG_KFENCE_STATIC_KEYS: either using
static keys to gate allocations, or using a simple dynamic branch),
always use a static branch to avoid the dynamic branch in kfence_alloc()
if KFENCE was disabled at boot.
For CONFIG_KFENCE_STATIC_KEYS=n, this now avoids the dynamic branch if
KFENCE was disabled at boot.
To simplify, also unifies the location where kfence_allocation_gate is
read-checked to just be inline in kfence_alloc().
Link: https://lkml.kernel.org/r/20211019102524.2807208-1-elver@google.com
Signed-off-by: Marco Elver <elver@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Jann Horn <jannh@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Initializing memory and setting/checking the canary bytes is relatively
expensive, and doing so in the meta->lock critical sections extends the
duration with preemption and interrupts disabled unnecessarily.
Any reads to meta->addr and meta->size in kfence_guarded_alloc() and
kfence_guarded_free() don't require locking meta->lock as long as the
object is removed from the freelist: only kfence_guarded_alloc() sets
meta->addr and meta->size after removing it from the freelist, which
requires a preceding kfence_guarded_free() returning it to the list or
the initial state.
Therefore move reads to meta->addr and meta->size, including expensive
memory initialization using them, out of meta->lock critical sections.
Link: https://lkml.kernel.org/r/20210930153706.2105471-1-elver@google.com
Signed-off-by: Marco Elver <elver@google.com>
Acked-by: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Jann Horn <jannh@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Use the new kunit_skip() to skip tests if requirements were not met. It
makes it easier to see in KUnit's summary if there were skipped tests.
Link: https://lkml.kernel.org/r/20210922182541.1372400-1-elver@google.com
Signed-off-by: Marco Elver <elver@google.com>
Reviewed-by: David Gow <davidgow@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Aleksandr Nogikh <nogikh@google.com>
Cc: Taras Madan <tarasmadan@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
One of KFENCE's main design principles is that with increasing uptime,
allocation coverage increases sufficiently to detect previously
undetected bugs.
We have observed that frequent long-lived allocations of the same source
(e.g. pagecache) tend to permanently fill up the KFENCE pool with
increasing system uptime, thus breaking the above requirement. The
workaround thus far had been increasing the sample interval and/or
increasing the KFENCE pool size, but is no reliable solution.
To ensure diverse coverage of allocations, limit currently covered
allocations of the same source once pool utilization reaches 75%
(configurable via `kfence.skip_covered_thresh`) or above. The effect is
retaining reasonable allocation coverage when the pool is close to full.
A side-effect is that this also limits frequent long-lived allocations
of the same source filling up the pool permanently.
Uniqueness of an allocation for coverage purposes is based on its
(partial) allocation stack trace (the source). A Counting Bloom filter
is used to check if an allocation is covered; if the allocation is
currently covered, the allocation is skipped by KFENCE.
Testing was done using:
(a) a synthetic workload that performs frequent long-lived
allocations (default config values; sample_interval=1;
num_objects=63), and
(b) normal desktop workloads on an otherwise idle machine where
the problem was first reported after a few days of uptime
(default config values).
In both test cases the sampled allocation rate no longer drops to zero
at any point. In the case of (b) we observe (after 2 days uptime) 15%
unique allocations in the pool, 77% pool utilization, with 20% "skipped
allocations (covered)".
[elver@google.com: simplify and just use hash_32(), use more random stack_hash_seed]
Link: https://lkml.kernel.org/r/YU3MRGaCaJiYht5g@elver.google.com
[elver@google.com: fix 32 bit]
Link: https://lkml.kernel.org/r/20210923104803.2620285-4-elver@google.com
Signed-off-by: Marco Elver <elver@google.com>
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
Acked-by: Alexander Potapenko <glider@google.com>
Cc: Aleksandr Nogikh <nogikh@google.com>
Cc: Jann Horn <jannh@google.com>
Cc: Taras Madan <tarasmadan@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Move the saving of the stack trace of allocations into __kfence_alloc(),
so that the stack entries array can be used outside of
kfence_guarded_alloc() and we avoid potentially unwinding the stack
multiple times.
Link: https://lkml.kernel.org/r/20210923104803.2620285-3-elver@google.com
Signed-off-by: Marco Elver <elver@google.com>
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
Acked-by: Alexander Potapenko <glider@google.com>
Cc: Aleksandr Nogikh <nogikh@google.com>
Cc: Jann Horn <jannh@google.com>
Cc: Taras Madan <tarasmadan@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Maintain a counter to count allocations that are skipped due to being
incompatible (oversized, incompatible gfp flags) or no capacity.
This is to compute the fraction of allocations that could not be
serviced by KFENCE, which we expect to be rare.
Link: https://lkml.kernel.org/r/20210923104803.2620285-2-elver@google.com
Signed-off-by: Marco Elver <elver@google.com>
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
Acked-by: Alexander Potapenko <glider@google.com>
Cc: Aleksandr Nogikh <nogikh@google.com>
Cc: Jann Horn <jannh@google.com>
Cc: Taras Madan <tarasmadan@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This has served its purpose and is no longer used. All usercopy
violations appear to have been handled by now, any remaining instances
(or new bugs) will cause copies to be rejected.
This isn't a direct revert of commit 2d891fbc3b ("usercopy: Allow
strict enforcement of whitelists"); since usercopy_fallback is
effectively 0, the fallback handling is removed too.
This also removes the usercopy_fallback module parameter on slab_common.
Link: https://github.com/KSPP/linux/issues/153
Link: https://lkml.kernel.org/r/20210921061149.1091163-1-steve@sk2.org
Signed-off-by: Stephen Kitt <steve@sk2.org>
Suggested-by: Kees Cook <keescook@chromium.org>
Acked-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Joel Stanley <joel@jms.id.au> [defconfig change]
Acked-by: David Rientjes <rientjes@google.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: James Morris <jmorris@namei.org>
Cc: "Serge E . Hallyn" <serge@hallyn.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
kmap_atomic() is being deprecated in favor of kmap_local_page().
Replace the uses of kmap_atomic() within the highmem code.
On profiling clear_huge_page() using ftrace an improvement of 62% was
observed on the below setup.
Setup:-
Below data has been collected on Qualcomm's SM7250 SoC THP enabled
(kernel v4.19.113) with only CPU-0(Cortex-A55) and CPU-7(Cortex-A76)
switched on and set to max frequency, also DDR set to perf governor.
FTRACE Data:-
Base data:-
Number of iterations: 48
Mean of allocation time: 349.5 us
std deviation: 74.5 us
v4 data:-
Number of iterations: 48
Mean of allocation time: 131 us
std deviation: 32.7 us
The following simple userspace experiment to allocate
100MB(BUF_SZ) of pages and writing to it gave us a good insight,
we observed an improvement of 42% in allocation and writing timings.
-------------------------------------------------------------
Test code snippet
-------------------------------------------------------------
clock_start();
buf = malloc(BUF_SZ); /* Allocate 100 MB of memory */
for(i=0; i < BUF_SZ_PAGES; i++)
{
*((int *)(buf + (i*PAGE_SIZE))) = 1;
}
clock_end();
-------------------------------------------------------------
Malloc test timings for 100MB anon allocation:-
Base data:-
Number of iterations: 100
Mean of allocation time: 31831 us
std deviation: 4286 us
v4 data:-
Number of iterations: 100
Mean of allocation time: 18193 us
std deviation: 4915 us
[willy@infradead.org: fix zero_user_segments()]
Link: https://lkml.kernel.org/r/YYVhHCJcm2DM2G9u@casper.infradead.org
Link: https://lkml.kernel.org/r/20210204073255.20769-2-prathu.baronia@oneplus.com
Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Prathu Baronia <prathu.baronia@oneplus.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There is one possible race window between zs_pool_dec_isolated() and
zs_unregister_migration() because wait_for_isolated_drain() checks the
isolated count without holding class->lock and there is no order inside
zs_pool_dec_isolated(). Thus the below race window could be possible:
zs_pool_dec_isolated zs_unregister_migration
check pool->destroying != 0
pool->destroying = true;
smp_mb();
wait_for_isolated_drain()
wait for pool->isolated_pages == 0
atomic_long_dec(&pool->isolated_pages);
atomic_long_read(&pool->isolated_pages) == 0
Since we observe the pool->destroying (false) before atomic_long_dec()
for pool->isolated_pages, waking pool->migration_wait up is missed.
Fix this by ensure checking pool->destroying happens after the
atomic_long_dec(&pool->isolated_pages).
Link: https://lkml.kernel.org/r/20210708115027.7557-1-linmiaohe@huawei.com
Fixes: 701d678599 ("mm/zsmalloc.c: fix race condition in zs_destroy_pool")
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Henry Burns <henryburns@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
During migration special page table entries are installed for each page
being migrated. These entries store the pfn and associated permissions
of ptes mapping the page being migarted.
Device-private pages use special swap pte entries to distinguish
read-only vs. writeable pages which the migration code checks when
creating migration entries. Normally this follows a fast path in
migrate_vma_collect_pmd() which correctly copies the permissions of
device-private pages over to migration entries when migrating pages back
to the CPU.
However the slow-path falls back to using try_to_migrate() which
unconditionally creates read-only migration entries for device-private
pages. This leads to unnecessary double faults on the CPU as the new
pages are always mapped read-only even when they could be mapped
writeable. Fix this by correctly copying device-private permissions in
try_to_migrate_one().
Link: https://lkml.kernel.org/r/20211018045247.3128058-1-apopple@nvidia.com
Signed-off-by: Alistair Popple <apopple@nvidia.com>
Reported-by: Ralph Campbell <rcampbell@nvidia.com>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Let's add a flag that corresponds to IORESOURCE_SYSRAM_DRIVER_MANAGED,
indicating that we're dealing with a memory region that is never
indicated in the firmware-provided memory map, but always detected and
added by a driver.
Similar to MEMBLOCK_HOTPLUG, most infrastructure has to treat such
memory regions like ordinary MEMBLOCK_NONE memory regions -- for
example, when selecting memory regions to add to the vmcore for dumping
in the crashkernel via for_each_mem_range().
However, especially kexec_file is not supposed to select such memblocks
via for_each_free_mem_range() / for_each_free_mem_range_reverse() to
place kexec images, similar to how we handle
IORESOURCE_SYSRAM_DRIVER_MANAGED without CONFIG_ARCH_KEEP_MEMBLOCK.
We'll make sure that memory hotplug code sets the flag where applicable
(IORESOURCE_SYSRAM_DRIVER_MANAGED) next. This prepares architectures
that need CONFIG_ARCH_KEEP_MEMBLOCK, such as arm64, for virtio-mem
support.
Note that kexec *must not* indicate this memory to the second kernel and
*must not* place kexec-images on this memory. Let's add a comment to
kexec_walk_memblock(), documenting how we handle MEMBLOCK_DRIVER_MANAGED
now just like using IORESOURCE_SYSRAM_DRIVER_MANAGED in
locate_mem_hole_callback() for kexec_walk_resources().
Also note that MEMBLOCK_HOTPLUG cannot be reused due to different
semantics:
MEMBLOCK_HOTPLUG: memory is indicated as "System RAM" in the
firmware-provided memory map and added to the system early during
boot; kexec *has to* indicate this memory to the second kernel and
can place kexec-images on this memory. After memory hotunplug,
kexec has to be re-armed. We mostly ignore this flag when
"movable_node" is not set on the kernel command line, because
then we're told to not care about hotunpluggability of such
memory regions.
MEMBLOCK_DRIVER_MANAGED: memory is not indicated as "System RAM" in
the firmware-provided memory map; this memory is always detected
and added to the system by a driver; memory might not actually be
physically hotunpluggable. kexec *must not* indicate this memory to
the second kernel and *must not* place kexec-images on this memory.
Link: https://lkml.kernel.org/r/20211004093605.5830-5-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Mike Rapoport <rppt@linux.ibm.com>
Cc: "Aneesh Kumar K . V" <aneesh.kumar@linux.ibm.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Jianyong Wu <Jianyong.Wu@arm.com>
Cc: Jiaxun Yang <jiaxun.yang@flygoat.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Shahab Vahedi <shahab@synopsys.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vineet Gupta <vgupta@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We want to specify flags when hotplugging memory. Let's prepare to pass
flags to memblock_add_node() by adjusting all existing users.
Note that when hotplugging memory the system is already up and running
and we might have concurrent memblock users: for example, while we're
hotplugging memory, kexec_file code might search for suitable memory
regions to place kexec images. It's important to add the memory
directly to memblock via a single call with the right flags, instead of
adding the memory first and apply flags later: otherwise, concurrent
memblock users might temporarily stumble over memblocks with wrong
flags, which will be important in a follow-up patch that introduces a
new flag to properly handle add_memory_driver_managed().
Link: https://lkml.kernel.org/r/20211004093605.5830-4-david@redhat.com
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Acked-by: Shahab Vahedi <shahab@synopsys.com> [arch/arc]
Reviewed-by: Mike Rapoport <rppt@linux.ibm.com>
Cc: "Aneesh Kumar K . V" <aneesh.kumar@linux.ibm.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Jianyong Wu <Jianyong.Wu@arm.com>
Cc: Jiaxun Yang <jiaxun.yang@flygoat.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vineet Gupta <vgupta@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "mm/memory_hotplug: full support for add_memory_driver_managed() with CONFIG_ARCH_KEEP_MEMBLOCK", v2.
Architectures that require CONFIG_ARCH_KEEP_MEMBLOCK=y, such as arm64,
don't cleanly support add_memory_driver_managed() yet. Most
prominently, kexec_file can still end up placing kexec images on such
driver-managed memory, resulting in undesired behavior, for example,
having kexec images located on memory not part of the firmware-provided
memory map.
Teaching kexec to not place images on driver-managed memory is
especially relevant for virtio-mem. Details can be found in commit
7b7b27214b ("mm/memory_hotplug: introduce
add_memory_driver_managed()").
Extend memblock with a new flag and set it from memory hotplug code when
applicable. This is required to fully support virtio-mem on arm64,
making also kexec_file behave like on x86-64.
This patch (of 2):
If memblock_add_node() fails, we're most probably running out of memory.
While this is unlikely to happen, it can happen and having memory added
without a memblock can be problematic for architectures that use
memblock to detect valid memory. Let's fail in a nice way instead of
silently ignoring the error.
Link: https://lkml.kernel.org/r/20211004093605.5830-1-david@redhat.com
Link: https://lkml.kernel.org/r/20211004093605.5830-2-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Jianyong Wu <Jianyong.Wu@arm.com>
Cc: "Aneesh Kumar K . V" <aneesh.kumar@linux.ibm.com>
Cc: Vineet Gupta <vgupta@kernel.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Jiaxun Yang <jiaxun.yang@flygoat.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Shahab Vahedi <shahab@synopsys.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We don't support CONFIG_MEMORY_HOTPLUG on 32 bit and consequently not
HIGHMEM. Let's remove any leftover code -- including the unused
"status_change_nid_high" field part of the memory notifier.
Link: https://lkml.kernel.org/r/20210929143600.49379-5-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: Alex Shi <alexs@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
32 bit support is broken in various ways: for example, we can online
memory that should actually go to ZONE_HIGHMEM to ZONE_MOVABLE or in
some cases even to one of the other kernel zones.
We marked it BROKEN in commit b59d02ed08 ("mm/memory_hotplug: disable
the functionality for 32b") almost one year ago. According to that
commit it might be broken at least since 2017. Further, there is hardly
a sane use case nowadays.
Let's just depend completely on 64bit, dropping the "BROKEN" dependency
to make clear that we are not going to support it again. Next, we'll
remove some HIGHMEM leftovers from memory hotplug code to clean up.
Link: https://lkml.kernel.org/r/20210929143600.49379-4-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: Alex Shi <alexs@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
CONFIG_MEMORY_HOTPLUG depends on CONFIG_SPARSEMEM, so there is no need for
CONFIG_MEMORY_HOTPLUG_SPARSE anymore; adjust all instances to use
CONFIG_MEMORY_HOTPLUG and remove CONFIG_MEMORY_HOTPLUG_SPARSE.
Link: https://lkml.kernel.org/r/20210929143600.49379-3-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Acked-by: Shuah Khan <skhan@linuxfoundation.org> [kselftest]
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Oscar Salvador <osalvador@suse.de>
Cc: Alex Shi <alexs@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "mm/memory_hotplug: Kconfig and 32 bit cleanups".
Some cleanups around CONFIG_MEMORY_HOTPLUG, including removing 32 bit
leftovers of memory hotplug support.
This patch (of 6):
SPARSEMEM is the only possible memory model for x86-64, FLATMEM is not
possible:
config ARCH_FLATMEM_ENABLE
def_bool y
depends on X86_32 && !NUMA
And X86_64_ACPI_NUMA (obviously) only supports x86-64:
config X86_64_ACPI_NUMA
def_bool y
depends on X86_64 && NUMA && ACPI && PCI
Let's just remove the CONFIG_X86_64_ACPI_NUMA dependency, as it does no
longer make sense.
Link: https://lkml.kernel.org/r/20210929143600.49379-2-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Alex Shi <alexs@kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
online_policy_to_str is only used in memory_hotplug.c and should be
defined as static.
Link: https://lkml.kernel.org/r/20210913024534.26161-1-tangyizhou@huawei.com
Signed-off-by: Tang Yizhou <tangyizhou@huawei.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
KCSAN reports a data-race on v5.10 which also exists on mainline:
BUG: KCSAN: data-race in extfrag_for_order+0x33/0x2d0
race at unknown origin, with read to 0xffff9ee9bfffab48 of 8 bytes by task 34 on cpu 1:
extfrag_for_order+0x33/0x2d0
kcompactd+0x5f0/0xce0
kthread+0x1f9/0x220
ret_from_fork+0x22/0x30
Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 34 Comm: kcompactd0 Not tainted 5.10.0+ #2
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014
Access to zone->free_area[order].nr_free in extfrag_for_order() and
frag_show_print() is lockless. That's intentional and the stats are a
rough estimate anyway. Annotate them with data_race().
[liushixin2@huawei.com: add comments]
Link: https://lkml.kernel.org/r/20210918084655.2696522-1-liushixin2@huawei.com
Link: https://lkml.kernel.org/r/20210908015606.3999871-1-liushixin2@huawei.com
Signed-off-by: Liu Shixin <liushixin2@huawei.com>
Cc: "Paul E . McKenney" <paulmck@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When nommu, the arch_get_unmapped_area() will not be called, just kill
it.
Link: https://lkml.kernel.org/r/20210910061906.36299-1-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In fact, formated values returned by get_init_ra_size are not that
intuitive. This patch make the comments reflect its truth.
Link: https://lkml.kernel.org/r/20211019104812.135602-1-linf@wangsu.com
Signed-off-by: Lin Feng <linf@wangsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The memory demotion needs to call migrate_pages() to do the jobs. And
it is controlled by a knob, however, the knob doesn't depend on
CONFIG_MIGRATION. The knob could be truned on even though MIGRATION is
disabled, this will not cause any crash since migrate_pages() would just
return -ENOSYS. But it is definitely not optimal to go through demotion
path then retry regular swap every time.
And it doesn't make too much sense to have the knob visible to the users
when !MIGRATION. Move the related code from mempolicy.[h|c] to
migrate.[h|c].
Link: https://lkml.kernel.org/r/20211015005559.246709-1-shy828301@gmail.com
Signed-off-by: Yang Shi <shy828301@gmail.com>
Acked-by: "Huang, Ying" <ying.huang@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In order to remove the need to manually keep three different files in
synch, provide a common definition of the mapping between enum
migrate_reason, and the associated strings for each enum item.
1. Use the tracing system's mapping of enums to strings, by redefining
and reusing the MIGRATE_REASON and supporting macros, and using that
to populate the string array in mm/debug.c.
2. Move enum migrate_reason to migrate_mode.h. This is not strictly
necessary for this patch, but migrate mode and migrate reason go
together, so this will slightly clarify things.
Link: https://lkml.kernel.org/r/20210922041755.141817-2-jhubbard@nvidia.com
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Reviewed-by: Weizhao Ouyang <o451686892@gmail.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We can specify the number of hugepages to allocate at boot. But the
hugepages is balanced in all nodes at present. In some scenarios, we
only need hugepages in one node. For example: DPDK needs hugepages
which are in the same node as NIC.
If DPDK needs four hugepages of 1G size in node1 and system has 16 numa
nodes we must reserve 64 hugepages on the kernel cmdline. But only four
hugepages are used. The others should be free after boot. If the
system memory is low(for example: 64G), it will be an impossible task.
So extend the hugepages parameter to support specifying hugepages on a
specific node. For example add following parameter:
hugepagesz=1G hugepages=0:1,1:3
It will allocate 1 hugepage in node0 and 3 hugepages in node1.
Link: https://lkml.kernel.org/r/20211005054729.86457-1-yaozhenguo1@gmail.com
Signed-off-by: Zhenguo Yao <yaozhenguo1@gmail.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Zhenguo Yao <yaozhenguo1@gmail.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The OOM reaper alters user address space which might theoretically alter
the snapshot if reaping is allowed to happen after the freezer quiescent
state. To this end, the reaper kthread uses wait_event_freezable()
while waiting for any work so that it cannot run while the system
freezes.
However, the current implementation doesn't respect the freezer because
all kernel threads are created with the PF_NOFREEZE flag, so they are
automatically excluded from freezing operations. This means that the
OOM reaper can race with system snapshotting if it has work to do while
the system is being frozen.
Fix this by adding a set_freezable() call which will clear the
PF_NOFREEZE flag and thus make the OOM reaper visible to the freezer.
Please note that the OOM reaper altering the snapshot this way is mostly
a theoretical concern and has not been observed in practice.
Link: https://lkml.kernel.org/r/20210921165758.6154-1-sultan@kerneltoast.com
Link: https://lkml.kernel.org/r/20210918233920.9174-1-sultan@kerneltoast.com
Fixes: aac4536355 ("mm, oom: introduce oom reaper")
Signed-off-by: Sultan Alsawaf <sultan@kerneltoast.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Mel Gorman <mgorman@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Rename memblock_free_ptr() to memblock_free() and use memblock_free()
when freeing a virtual pointer so that memblock_free() will be a
counterpart of memblock_alloc()
The callers are updated with the below semantic patch and manual
addition of (void *) casting to pointers that are represented by
unsigned long variables.
@@
identifier vaddr;
expression size;
@@
(
- memblock_phys_free(__pa(vaddr), size);
+ memblock_free(vaddr, size);
|
- memblock_free_ptr(vaddr, size);
+ memblock_free(vaddr, size);
)
[sfr@canb.auug.org.au: fixup]
Link: https://lkml.kernel.org/r/20211018192940.3d1d532f@canb.auug.org.au
Link: https://lkml.kernel.org/r/20210930185031.18648-7-rppt@kernel.org
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Juergen Gross <jgross@suse.com>
Cc: Shahab Vahedi <Shahab.Vahedi@synopsys.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Since memblock_free() operates on a physical range, make its name
reflect it and rename it to memblock_phys_free(), so it will be a
logical counterpart to memblock_phys_alloc().
The callers are updated with the below semantic patch:
@@
expression addr;
expression size;
@@
- memblock_free(addr, size);
+ memblock_phys_free(addr, size);
Link: https://lkml.kernel.org/r/20210930185031.18648-6-rppt@kernel.org
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Juergen Gross <jgross@suse.com>
Cc: Shahab Vahedi <Shahab.Vahedi@synopsys.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
memblock_free_late() is a NOP wrapper for __memblock_free_late(), there
is no point to keep this indirection.
Drop the wrapper and rename __memblock_free_late() to
memblock_free_late().
Link: https://lkml.kernel.org/r/20210930185031.18648-5-rppt@kernel.org
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Juergen Gross <jgross@suse.com>
Cc: Shahab Vahedi <Shahab.Vahedi@synopsys.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
memblock_free_early_nid() is unused and memblock_free_early() is an
alias for memblock_free().
Replace calls to memblock_free_early() with calls to memblock_free() and
remove memblock_free_early() and memblock_free_early_nid().
Link: https://lkml.kernel.org/r/20210930185031.18648-4-rppt@kernel.org
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Juergen Gross <jgross@suse.com>
Cc: Shahab Vahedi <Shahab.Vahedi@synopsys.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When reading memcg->socket_pressure in mem_cgroup_under_socket_pressure()
and writing memcg->socket_pressure in vmpressure() at the same time, the
following data-race occurs:
BUG: KCSAN: data-race in __sk_mem_reduce_allocated / vmpressure
write to 0xffff8881286f4938 of 8 bytes by task 24550 on cpu 3:
vmpressure+0x218/0x230 mm/vmpressure.c:307
shrink_node_memcgs+0x2b9/0x410 mm/vmscan.c:2658
shrink_node+0x9d2/0x11d0 mm/vmscan.c:2769
shrink_zones+0x29f/0x470 mm/vmscan.c:2972
do_try_to_free_pages+0x193/0x6e0 mm/vmscan.c:3027
try_to_free_mem_cgroup_pages+0x1c0/0x3f0 mm/vmscan.c:3345
reclaim_high mm/memcontrol.c:2440 [inline]
mem_cgroup_handle_over_high+0x18b/0x4d0 mm/memcontrol.c:2624
tracehook_notify_resume include/linux/tracehook.h:197 [inline]
exit_to_user_mode_loop kernel/entry/common.c:164 [inline]
exit_to_user_mode_prepare+0x110/0x170 kernel/entry/common.c:191
syscall_exit_to_user_mode+0x16/0x30 kernel/entry/common.c:266
ret_from_fork+0x15/0x30 arch/x86/entry/entry_64.S:289
read to 0xffff8881286f4938 of 8 bytes by interrupt on cpu 1:
mem_cgroup_under_socket_pressure include/linux/memcontrol.h:1483 [inline]
sk_under_memory_pressure include/net/sock.h:1314 [inline]
__sk_mem_reduce_allocated+0x1d2/0x270 net/core/sock.c:2696
__sk_mem_reclaim+0x44/0x50 net/core/sock.c:2711
sk_mem_reclaim include/net/sock.h:1490 [inline]
......
net_rx_action+0x17a/0x480 net/core/dev.c:6864
__do_softirq+0x12c/0x2af kernel/softirq.c:298
run_ksoftirqd+0x13/0x20 kernel/softirq.c:653
smpboot_thread_fn+0x33f/0x510 kernel/smpboot.c:165
kthread+0x1fc/0x220 kernel/kthread.c:292
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296
Fix it by using READ_ONCE() and WRITE_ONCE() to read and write
memcg->socket_pressure.
Link: https://lkml.kernel.org/r/20211025082843.671690-1-songyuanzheng@huawei.com
Signed-off-by: Yuanzheng Song <songyuanzheng@huawei.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Roman Gushchin <guro@fb.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Alex Shi <alexs@kernel.org>
Cc: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Tracing indicates that tasks throttled on NOPROGRESS are woken
prematurely resulting in occasional massive spikes in direct reclaim
activity. This patch wakes tasks throttled on NOPROGRESS if reclaim
efficiency is at least 12%.
Link: https://lkml.kernel.org/r/20211022144651.19914-9-mgorman@techsingularity.net
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: "Darrick J . Wong" <djwong@kernel.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: NeilBrown <neilb@suse.de>
Cc: Rik van Riel <riel@surriel.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Tracing of the stutterp workload showed the following delays
1 usect_delayed=124000 reason=VMSCAN_THROTTLE_NOPROGRESS
1 usect_delayed=128000 reason=VMSCAN_THROTTLE_NOPROGRESS
1 usect_delayed=176000 reason=VMSCAN_THROTTLE_NOPROGRESS
1 usect_delayed=536000 reason=VMSCAN_THROTTLE_NOPROGRESS
1 usect_delayed=544000 reason=VMSCAN_THROTTLE_NOPROGRESS
1 usect_delayed=556000 reason=VMSCAN_THROTTLE_NOPROGRESS
1 usect_delayed=624000 reason=VMSCAN_THROTTLE_NOPROGRESS
1 usect_delayed=716000 reason=VMSCAN_THROTTLE_NOPROGRESS
1 usect_delayed=772000 reason=VMSCAN_THROTTLE_NOPROGRESS
2 usect_delayed=512000 reason=VMSCAN_THROTTLE_NOPROGRESS
16 usect_delayed=120000 reason=VMSCAN_THROTTLE_NOPROGRESS
53 usect_delayed=116000 reason=VMSCAN_THROTTLE_NOPROGRESS
116 usect_delayed=112000 reason=VMSCAN_THROTTLE_NOPROGRESS
5907 usect_delayed=108000 reason=VMSCAN_THROTTLE_NOPROGRESS
71741 usect_delayed=104000 reason=VMSCAN_THROTTLE_NOPROGRESS
All the throttling hit the full timeout and then there was wakeup delays
meaning that the wakeups are premature as no other reclaimer such as
kswapd has made progress. This patch increases the maximum timeout.
Link: https://lkml.kernel.org/r/20211022144651.19914-8-mgorman@techsingularity.net
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: "Darrick J . Wong" <djwong@kernel.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: NeilBrown <neilb@suse.de>
Cc: Rik van Riel <riel@surriel.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Neil Brown raised concerns about callers of reclaim_throttle specifying
a timeout value. The original timeout values to congestion_wait() were
probably pulled out of thin air or copy&pasted from somewhere else.
This patch centralises the timeout values and selects a timeout based on
the reason for reclaim throttling. These figures are also pulled out of
the same thin air but better values may be derived
Running a workload that is throttling for inappropriate periods and
tracing mm_vmscan_throttled can be used to pick a more appropriate
value. Excessive throttling would pick a lower timeout where as
excessive CPU usage in reclaim context would select a larger timeout.
Ideally a large value would always be used and the wakeups would occur
before a timeout but that requires careful testing.
Link: https://lkml.kernel.org/r/20211022144651.19914-7-mgorman@techsingularity.net
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: "Darrick J . Wong" <djwong@kernel.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: NeilBrown <neilb@suse.de>
Cc: Rik van Riel <riel@surriel.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The page allocator stalls based on the number of pages that are waiting
for writeback to start but this should now be redundant.
shrink_inactive_list() will wake flusher threads if the LRU tail are
unqueued dirty pages so the flusher should be active. If it fails to
make progress due to pages under writeback not being completed quickly
then it should stall on VMSCAN_THROTTLE_WRITEBACK.
Link: https://lkml.kernel.org/r/20211022144651.19914-6-mgorman@techsingularity.net
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: "Darrick J . Wong" <djwong@kernel.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: NeilBrown <neilb@suse.de>
Cc: Rik van Riel <riel@surriel.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
do_writepages throttles on congestion if the writepages() fails due to a
lack of memory but congestion_wait() is partially broken as the
congestion state is not updated for all BDIs.
This patch stalls waiting for a number of pages to complete writeback
that located on the local node. The main weakness is that there is no
correlation between the location of the inode's pages and locality but
that is still better than congestion_wait.
Link: https://lkml.kernel.org/r/20211022144651.19914-5-mgorman@techsingularity.net
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: "Darrick J . Wong" <djwong@kernel.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: NeilBrown <neilb@suse.de>
Cc: Rik van Riel <riel@surriel.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Memcg reclaim throttles on congestion if no reclaim progress is made.
This makes little sense, it might be due to writeback or a host of other
factors.
For !memcg reclaim, it's messy. Direct reclaim primarily is throttled
in the page allocator if it is failing to make progress. Kswapd
throttles if too many pages are under writeback and marked for immediate
reclaim.
This patch explicitly throttles if reclaim is failing to make progress.
[vbabka@suse.cz: Remove redundant code]
Link: https://lkml.kernel.org/r/20211022144651.19914-4-mgorman@techsingularity.net
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: "Darrick J . Wong" <djwong@kernel.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: NeilBrown <neilb@suse.de>
Cc: Rik van Riel <riel@surriel.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Page reclaim throttles on congestion if too many parallel reclaim
instances have isolated too many pages. This makes no sense, excessive
parallelisation has nothing to do with writeback or congestion.
This patch creates an additional workqueue to sleep on when too many
pages are isolated. The throttled tasks are woken when the number of
isolated pages is reduced or a timeout occurs. There may be some false
positive wakeups for GFP_NOIO/GFP_NOFS callers but the tasks will
throttle again if necessary.
[shy828301@gmail.com: Wake up from compaction context]
[vbabka@suse.cz: Account number of throttled tasks only for writeback]
Link: https://lkml.kernel.org/r/20211022144651.19914-3-mgorman@techsingularity.net
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: "Darrick J . Wong" <djwong@kernel.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: NeilBrown <neilb@suse.de>
Cc: Rik van Riel <riel@surriel.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "Remove dependency on congestion_wait in mm/", v5.
This series that removes all calls to congestion_wait in mm/ and deletes
wait_iff_congested. It's not a clever implementation but
congestion_wait has been broken for a long time [1].
Even if congestion throttling worked, it was never a great idea. While
excessive dirty/writeback pages at the tail of the LRU is one
possibility that reclaim may be slow, there is also the problem of too
many pages being isolated and reclaim failing for other reasons
(elevated references, too many pages isolated, excessive LRU contention
etc).
This series replaces the "congestion" throttling with 3 different types.
- If there are too many dirty/writeback pages, sleep until a timeout or
enough pages get cleaned
- If too many pages are isolated, sleep until enough isolated pages are
either reclaimed or put back on the LRU
- If no progress is being made, direct reclaim tasks sleep until
another task makes progress with acceptable efficiency.
This was initially tested with a mix of workloads that used to trigger
corner cases that no longer work. A new test case was created called
"stutterp" (pagereclaim-stutterp-noreaders in mmtests) using a freshly
created XFS filesystem. Note that it may be necessary to increase the
timeout of ssh if executing remotely as ssh itself can get throttled and
the connection may timeout.
stutterp varies the number of "worker" processes from 4 up to NR_CPUS*4
to check the impact as the number of direct reclaimers increase. It has
four types of worker.
- One "anon latency" worker creates small mappings with mmap() and
times how long it takes to fault the mapping reading it 4K at a time
- X file writers which is fio randomly writing X files where the total
size of the files add up to the allowed dirty_ratio. fio is allowed
to run for a warmup period to allow some file-backed pages to
accumulate. The duration of the warmup is based on the best-case
linear write speed of the storage.
- Y file readers which is fio randomly reading small files
- Z anon memory hogs which continually map (100-dirty_ratio)% of memory
- Total estimated WSS = (100+dirty_ration) percentage of memory
X+Y+Z+1 == NR_WORKERS varying from 4 up to NR_CPUS*4
The intent is to maximise the total WSS with a mix of file and anon
memory where some anonymous memory must be swapped and there is a high
likelihood of dirty/writeback pages reaching the end of the LRU.
The test can be configured to have no background readers to stress
dirty/writeback pages. The results below are based on having zero
readers.
The short summary of the results is that the series works and stalls
until some event occurs but the timeouts may need adjustment.
The test results are not broken down by patch as the series should be
treated as one block that replaces a broken throttling mechanism with a
working one.
Finally, three machines were tested but I'm reporting the worst set of
results. The other two machines had much better latencies for example.
First the results of the "anon latency" latency
stutterp
5.15.0-rc1 5.15.0-rc1
vanilla mm-reclaimcongest-v5r4
Amean mmap-4 31.4003 ( 0.00%) 2661.0198 (-8374.52%)
Amean mmap-7 38.1641 ( 0.00%) 149.2891 (-291.18%)
Amean mmap-12 60.0981 ( 0.00%) 187.8105 (-212.51%)
Amean mmap-21 161.2699 ( 0.00%) 213.9107 ( -32.64%)
Amean mmap-30 174.5589 ( 0.00%) 377.7548 (-116.41%)
Amean mmap-48 8106.8160 ( 0.00%) 1070.5616 ( 86.79%)
Stddev mmap-4 41.3455 ( 0.00%) 27573.9676 (-66591.66%)
Stddev mmap-7 53.5556 ( 0.00%) 4608.5860 (-8505.23%)
Stddev mmap-12 171.3897 ( 0.00%) 5559.4542 (-3143.75%)
Stddev mmap-21 1506.6752 ( 0.00%) 5746.2507 (-281.39%)
Stddev mmap-30 557.5806 ( 0.00%) 7678.1624 (-1277.05%)
Stddev mmap-48 61681.5718 ( 0.00%) 14507.2830 ( 76.48%)
Max-90 mmap-4 31.4243 ( 0.00%) 83.1457 (-164.59%)
Max-90 mmap-7 41.0410 ( 0.00%) 41.0720 ( -0.08%)
Max-90 mmap-12 66.5255 ( 0.00%) 53.9073 ( 18.97%)
Max-90 mmap-21 146.7479 ( 0.00%) 105.9540 ( 27.80%)
Max-90 mmap-30 193.9513 ( 0.00%) 64.3067 ( 66.84%)
Max-90 mmap-48 277.9137 ( 0.00%) 591.0594 (-112.68%)
Max mmap-4 1913.8009 ( 0.00%) 299623.9695 (-15555.96%)
Max mmap-7 2423.9665 ( 0.00%) 204453.1708 (-8334.65%)
Max mmap-12 6845.6573 ( 0.00%) 221090.3366 (-3129.64%)
Max mmap-21 56278.6508 ( 0.00%) 213877.3496 (-280.03%)
Max mmap-30 19716.2990 ( 0.00%) 216287.6229 (-997.00%)
Max mmap-48 477923.9400 ( 0.00%) 245414.8238 ( 48.65%)
For most thread counts, the time to mmap() is unfortunately increased.
In earlier versions of the series, this was lower but a large number of
throttling events were reaching their timeout increasing the amount of
inefficient scanning of the LRU. There is no prioritisation of reclaim
tasks making progress based on each tasks rate of page allocation versus
progress of reclaim. The variance is also impacted for high worker
counts but in all cases, the differences in latency are not
statistically significant due to very large maximum outliers. Max-90
shows that 90% of the stalls are comparable but the Max results show the
massive outliers which are increased to to stalling.
It is expected that this will be very machine dependant. Due to the
test design, reclaim is difficult so allocations stall and there are
variances depending on whether THPs can be allocated or not. The amount
of memory will affect exactly how bad the corner cases are and how often
they trigger. The warmup period calculation is not ideal as it's based
on linear writes where as fio is randomly writing multiple files from
multiple tasks so the start state of the test is variable. For example,
these are the latencies on a single-socket machine that had more memory
Amean mmap-4 42.2287 ( 0.00%) 49.6838 * -17.65%*
Amean mmap-7 216.4326 ( 0.00%) 47.4451 * 78.08%*
Amean mmap-12 2412.0588 ( 0.00%) 51.7497 ( 97.85%)
Amean mmap-21 5546.2548 ( 0.00%) 51.8862 ( 99.06%)
Amean mmap-30 1085.3121 ( 0.00%) 72.1004 ( 93.36%)
The overall system CPU usage and elapsed time is as follows
5.15.0-rc3 5.15.0-rc3
vanilla mm-reclaimcongest-v5r4
Duration User 6989.03 983.42
Duration System 7308.12 799.68
Duration Elapsed 2277.67 2092.98
The patches reduce system CPU usage by 89% as the vanilla kernel is rarely
stalling.
The high-level /proc/vmstats show
5.15.0-rc1 5.15.0-rc1
vanilla mm-reclaimcongest-v5r2
Ops Direct pages scanned 1056608451.00 503594991.00
Ops Kswapd pages scanned 109795048.00 147289810.00
Ops Kswapd pages reclaimed 63269243.00 31036005.00
Ops Direct pages reclaimed 10803973.00 6328887.00
Ops Kswapd efficiency % 57.62 21.07
Ops Kswapd velocity 48204.98 57572.86
Ops Direct efficiency % 1.02 1.26
Ops Direct velocity 463898.83 196845.97
Kswapd scanned less pages but the detailed pattern is different. The
vanilla kernel scans slowly over time where as the patches exhibits
burst patterns of scan activity. Direct reclaim scanning is reduced by
52% due to stalling.
The pattern for stealing pages is also slightly different. Both kernels
exhibit spikes but the vanilla kernel when reclaiming shows pages being
reclaimed over a period of time where as the patches tend to reclaim in
spikes. The difference is that vanilla is not throttling and instead
scanning constantly finding some pages over time where as the patched
kernel throttles and reclaims in spikes.
Ops Percentage direct scans 90.59 77.37
For direct reclaim, vanilla scanned 90.59% of pages where as with the
patches, 77.37% were direct reclaim due to throttling
Ops Page writes by reclaim 2613590.00 1687131.00
Page writes from reclaim context are reduced.
Ops Page writes anon 2932752.00 1917048.00
And there is less swapping.
Ops Page reclaim immediate 996248528.00 107664764.00
The number of pages encountered at the tail of the LRU tagged for
immediate reclaim but still dirty/writeback is reduced by 89%.
Ops Slabs scanned 164284.00 153608.00
Slab scan activity is similar.
ftrace was used to gather stall activity
Vanilla
-------
1 writeback_wait_iff_congested: usec_timeout=100000 usec_delayed=16000
2 writeback_wait_iff_congested: usec_timeout=100000 usec_delayed=12000
8 writeback_wait_iff_congested: usec_timeout=100000 usec_delayed=8000
29 writeback_wait_iff_congested: usec_timeout=100000 usec_delayed=4000
82394 writeback_wait_iff_congested: usec_timeout=100000 usec_delayed=0
The fast majority of wait_iff_congested calls do not stall at all. What
is likely happening is that cond_resched() reschedules the task for a
short period when the BDI is not registering congestion (which it never
will in this test setup).
1 writeback_congestion_wait: usec_timeout=100000 usec_delayed=120000
2 writeback_congestion_wait: usec_timeout=100000 usec_delayed=132000
4 writeback_congestion_wait: usec_timeout=100000 usec_delayed=112000
380 writeback_congestion_wait: usec_timeout=100000 usec_delayed=108000
778 writeback_congestion_wait: usec_timeout=100000 usec_delayed=104000
congestion_wait if called always exceeds the timeout as there is no
trigger to wake it up.
Bottom line: Vanilla will throttle but it's not effective.
Patch series
------------
Kswapd throttle activity was always due to scanning pages tagged for
immediate reclaim at the tail of the LRU
1 usec_timeout=100000 usect_delayed=72000 reason=VMSCAN_THROTTLE_WRITEBACK
4 usec_timeout=100000 usect_delayed=20000 reason=VMSCAN_THROTTLE_WRITEBACK
5 usec_timeout=100000 usect_delayed=12000 reason=VMSCAN_THROTTLE_WRITEBACK
6 usec_timeout=100000 usect_delayed=16000 reason=VMSCAN_THROTTLE_WRITEBACK
11 usec_timeout=100000 usect_delayed=100000 reason=VMSCAN_THROTTLE_WRITEBACK
11 usec_timeout=100000 usect_delayed=8000 reason=VMSCAN_THROTTLE_WRITEBACK
94 usec_timeout=100000 usect_delayed=0 reason=VMSCAN_THROTTLE_WRITEBACK
112 usec_timeout=100000 usect_delayed=4000 reason=VMSCAN_THROTTLE_WRITEBACK
The majority of events did not stall or stalled for a short period.
Roughly 16% of stalls reached the timeout before expiry. For direct
reclaim, the number of times stalled for each reason were
6624 reason=VMSCAN_THROTTLE_ISOLATED
93246 reason=VMSCAN_THROTTLE_NOPROGRESS
96934 reason=VMSCAN_THROTTLE_WRITEBACK
The most common reason to stall was due to excessive pages tagged for
immediate reclaim at the tail of the LRU followed by a failure to make
forward. A relatively small number were due to too many pages isolated
from the LRU by parallel threads
For VMSCAN_THROTTLE_ISOLATED, the breakdown of delays was
9 usec_timeout=20000 usect_delayed=4000 reason=VMSCAN_THROTTLE_ISOLATED
12 usec_timeout=20000 usect_delayed=16000 reason=VMSCAN_THROTTLE_ISOLATED
83 usec_timeout=20000 usect_delayed=20000 reason=VMSCAN_THROTTLE_ISOLATED
6520 usec_timeout=20000 usect_delayed=0 reason=VMSCAN_THROTTLE_ISOLATED
Most did not stall at all. A small number reached the timeout.
For VMSCAN_THROTTLE_NOPROGRESS, the breakdown of stalls were all over
the map
1 usec_timeout=500000 usect_delayed=324000 reason=VMSCAN_THROTTLE_NOPROGRESS
1 usec_timeout=500000 usect_delayed=332000 reason=VMSCAN_THROTTLE_NOPROGRESS
1 usec_timeout=500000 usect_delayed=348000 reason=VMSCAN_THROTTLE_NOPROGRESS
1 usec_timeout=500000 usect_delayed=360000 reason=VMSCAN_THROTTLE_NOPROGRESS
2 usec_timeout=500000 usect_delayed=228000 reason=VMSCAN_THROTTLE_NOPROGRESS
2 usec_timeout=500000 usect_delayed=260000 reason=VMSCAN_THROTTLE_NOPROGRESS
2 usec_timeout=500000 usect_delayed=340000 reason=VMSCAN_THROTTLE_NOPROGRESS
2 usec_timeout=500000 usect_delayed=364000 reason=VMSCAN_THROTTLE_NOPROGRESS
2 usec_timeout=500000 usect_delayed=372000 reason=VMSCAN_THROTTLE_NOPROGRESS
2 usec_timeout=500000 usect_delayed=428000 reason=VMSCAN_THROTTLE_NOPROGRESS
2 usec_timeout=500000 usect_delayed=460000 reason=VMSCAN_THROTTLE_NOPROGRESS
2 usec_timeout=500000 usect_delayed=464000 reason=VMSCAN_THROTTLE_NOPROGRESS
3 usec_timeout=500000 usect_delayed=244000 reason=VMSCAN_THROTTLE_NOPROGRESS
3 usec_timeout=500000 usect_delayed=252000 reason=VMSCAN_THROTTLE_NOPROGRESS
3 usec_timeout=500000 usect_delayed=272000 reason=VMSCAN_THROTTLE_NOPROGRESS
4 usec_timeout=500000 usect_delayed=188000 reason=VMSCAN_THROTTLE_NOPROGRESS
4 usec_timeout=500000 usect_delayed=268000 reason=VMSCAN_THROTTLE_NOPROGRESS
4 usec_timeout=500000 usect_delayed=328000 reason=VMSCAN_THROTTLE_NOPROGRESS
4 usec_timeout=500000 usect_delayed=380000 reason=VMSCAN_THROTTLE_NOPROGRESS
4 usec_timeout=500000 usect_delayed=392000 reason=VMSCAN_THROTTLE_NOPROGRESS
4 usec_timeout=500000 usect_delayed=432000 reason=VMSCAN_THROTTLE_NOPROGRESS
5 usec_timeout=500000 usect_delayed=204000 reason=VMSCAN_THROTTLE_NOPROGRESS
5 usec_timeout=500000 usect_delayed=220000 reason=VMSCAN_THROTTLE_NOPROGRESS
5 usec_timeout=500000 usect_delayed=412000 reason=VMSCAN_THROTTLE_NOPROGRESS
5 usec_timeout=500000 usect_delayed=436000 reason=VMSCAN_THROTTLE_NOPROGRESS
6 usec_timeout=500000 usect_delayed=488000 reason=VMSCAN_THROTTLE_NOPROGRESS
7 usec_timeout=500000 usect_delayed=212000 reason=VMSCAN_THROTTLE_NOPROGRESS
7 usec_timeout=500000 usect_delayed=300000 reason=VMSCAN_THROTTLE_NOPROGRESS
7 usec_timeout=500000 usect_delayed=316000 reason=VMSCAN_THROTTLE_NOPROGRESS
7 usec_timeout=500000 usect_delayed=472000 reason=VMSCAN_THROTTLE_NOPROGRESS
8 usec_timeout=500000 usect_delayed=248000 reason=VMSCAN_THROTTLE_NOPROGRESS
8 usec_timeout=500000 usect_delayed=356000 reason=VMSCAN_THROTTLE_NOPROGRESS
8 usec_timeout=500000 usect_delayed=456000 reason=VMSCAN_THROTTLE_NOPROGRESS
9 usec_timeout=500000 usect_delayed=124000 reason=VMSCAN_THROTTLE_NOPROGRESS
9 usec_timeout=500000 usect_delayed=376000 reason=VMSCAN_THROTTLE_NOPROGRESS
9 usec_timeout=500000 usect_delayed=484000 reason=VMSCAN_THROTTLE_NOPROGRESS
10 usec_timeout=500000 usect_delayed=172000 reason=VMSCAN_THROTTLE_NOPROGRESS
10 usec_timeout=500000 usect_delayed=420000 reason=VMSCAN_THROTTLE_NOPROGRESS
10 usec_timeout=500000 usect_delayed=452000 reason=VMSCAN_THROTTLE_NOPROGRESS
11 usec_timeout=500000 usect_delayed=256000 reason=VMSCAN_THROTTLE_NOPROGRESS
12 usec_timeout=500000 usect_delayed=112000 reason=VMSCAN_THROTTLE_NOPROGRESS
12 usec_timeout=500000 usect_delayed=116000 reason=VMSCAN_THROTTLE_NOPROGRESS
12 usec_timeout=500000 usect_delayed=144000 reason=VMSCAN_THROTTLE_NOPROGRESS
12 usec_timeout=500000 usect_delayed=152000 reason=VMSCAN_THROTTLE_NOPROGRESS
12 usec_timeout=500000 usect_delayed=264000 reason=VMSCAN_THROTTLE_NOPROGRESS
12 usec_timeout=500000 usect_delayed=384000 reason=VMSCAN_THROTTLE_NOPROGRESS
12 usec_timeout=500000 usect_delayed=424000 reason=VMSCAN_THROTTLE_NOPROGRESS
12 usec_timeout=500000 usect_delayed=492000 reason=VMSCAN_THROTTLE_NOPROGRESS
13 usec_timeout=500000 usect_delayed=184000 reason=VMSCAN_THROTTLE_NOPROGRESS
13 usec_timeout=500000 usect_delayed=444000 reason=VMSCAN_THROTTLE_NOPROGRESS
14 usec_timeout=500000 usect_delayed=308000 reason=VMSCAN_THROTTLE_NOPROGRESS
14 usec_timeout=500000 usect_delayed=440000 reason=VMSCAN_THROTTLE_NOPROGRESS
14 usec_timeout=500000 usect_delayed=476000 reason=VMSCAN_THROTTLE_NOPROGRESS
16 usec_timeout=500000 usect_delayed=140000 reason=VMSCAN_THROTTLE_NOPROGRESS
17 usec_timeout=500000 usect_delayed=232000 reason=VMSCAN_THROTTLE_NOPROGRESS
17 usec_timeout=500000 usect_delayed=240000 reason=VMSCAN_THROTTLE_NOPROGRESS
17 usec_timeout=500000 usect_delayed=280000 reason=VMSCAN_THROTTLE_NOPROGRESS
18 usec_timeout=500000 usect_delayed=404000 reason=VMSCAN_THROTTLE_NOPROGRESS
20 usec_timeout=500000 usect_delayed=148000 reason=VMSCAN_THROTTLE_NOPROGRESS
20 usec_timeout=500000 usect_delayed=216000 reason=VMSCAN_THROTTLE_NOPROGRESS
20 usec_timeout=500000 usect_delayed=468000 reason=VMSCAN_THROTTLE_NOPROGRESS
21 usec_timeout=500000 usect_delayed=448000 reason=VMSCAN_THROTTLE_NOPROGRESS
23 usec_timeout=500000 usect_delayed=168000 reason=VMSCAN_THROTTLE_NOPROGRESS
23 usec_timeout=500000 usect_delayed=296000 reason=VMSCAN_THROTTLE_NOPROGRESS
25 usec_timeout=500000 usect_delayed=132000 reason=VMSCAN_THROTTLE_NOPROGRESS
25 usec_timeout=500000 usect_delayed=352000 reason=VMSCAN_THROTTLE_NOPROGRESS
26 usec_timeout=500000 usect_delayed=180000 reason=VMSCAN_THROTTLE_NOPROGRESS
27 usec_timeout=500000 usect_delayed=284000 reason=VMSCAN_THROTTLE_NOPROGRESS
28 usec_timeout=500000 usect_delayed=164000 reason=VMSCAN_THROTTLE_NOPROGRESS
29 usec_timeout=500000 usect_delayed=136000 reason=VMSCAN_THROTTLE_NOPROGRESS
30 usec_timeout=500000 usect_delayed=200000 reason=VMSCAN_THROTTLE_NOPROGRESS
30 usec_timeout=500000 usect_delayed=400000 reason=VMSCAN_THROTTLE_NOPROGRESS
31 usec_timeout=500000 usect_delayed=196000 reason=VMSCAN_THROTTLE_NOPROGRESS
32 usec_timeout=500000 usect_delayed=156000 reason=VMSCAN_THROTTLE_NOPROGRESS
33 usec_timeout=500000 usect_delayed=224000 reason=VMSCAN_THROTTLE_NOPROGRESS
35 usec_timeout=500000 usect_delayed=128000 reason=VMSCAN_THROTTLE_NOPROGRESS
35 usec_timeout=500000 usect_delayed=176000 reason=VMSCAN_THROTTLE_NOPROGRESS
36 usec_timeout=500000 usect_delayed=368000 reason=VMSCAN_THROTTLE_NOPROGRESS
36 usec_timeout=500000 usect_delayed=496000 reason=VMSCAN_THROTTLE_NOPROGRESS
37 usec_timeout=500000 usect_delayed=312000 reason=VMSCAN_THROTTLE_NOPROGRESS
38 usec_timeout=500000 usect_delayed=304000 reason=VMSCAN_THROTTLE_NOPROGRESS
40 usec_timeout=500000 usect_delayed=288000 reason=VMSCAN_THROTTLE_NOPROGRESS
43 usec_timeout=500000 usect_delayed=408000 reason=VMSCAN_THROTTLE_NOPROGRESS
55 usec_timeout=500000 usect_delayed=416000 reason=VMSCAN_THROTTLE_NOPROGRESS
56 usec_timeout=500000 usect_delayed=76000 reason=VMSCAN_THROTTLE_NOPROGRESS
58 usec_timeout=500000 usect_delayed=120000 reason=VMSCAN_THROTTLE_NOPROGRESS
59 usec_timeout=500000 usect_delayed=208000 reason=VMSCAN_THROTTLE_NOPROGRESS
61 usec_timeout=500000 usect_delayed=68000 reason=VMSCAN_THROTTLE_NOPROGRESS
71 usec_timeout=500000 usect_delayed=192000 reason=VMSCAN_THROTTLE_NOPROGRESS
71 usec_timeout=500000 usect_delayed=480000 reason=VMSCAN_THROTTLE_NOPROGRESS
79 usec_timeout=500000 usect_delayed=60000 reason=VMSCAN_THROTTLE_NOPROGRESS
82 usec_timeout=500000 usect_delayed=320000 reason=VMSCAN_THROTTLE_NOPROGRESS
82 usec_timeout=500000 usect_delayed=92000 reason=VMSCAN_THROTTLE_NOPROGRESS
85 usec_timeout=500000 usect_delayed=64000 reason=VMSCAN_THROTTLE_NOPROGRESS
85 usec_timeout=500000 usect_delayed=80000 reason=VMSCAN_THROTTLE_NOPROGRESS
88 usec_timeout=500000 usect_delayed=84000 reason=VMSCAN_THROTTLE_NOPROGRESS
90 usec_timeout=500000 usect_delayed=160000 reason=VMSCAN_THROTTLE_NOPROGRESS
90 usec_timeout=500000 usect_delayed=292000 reason=VMSCAN_THROTTLE_NOPROGRESS
94 usec_timeout=500000 usect_delayed=56000 reason=VMSCAN_THROTTLE_NOPROGRESS
118 usec_timeout=500000 usect_delayed=88000 reason=VMSCAN_THROTTLE_NOPROGRESS
119 usec_timeout=500000 usect_delayed=72000 reason=VMSCAN_THROTTLE_NOPROGRESS
126 usec_timeout=500000 usect_delayed=108000 reason=VMSCAN_THROTTLE_NOPROGRESS
146 usec_timeout=500000 usect_delayed=52000 reason=VMSCAN_THROTTLE_NOPROGRESS
148 usec_timeout=500000 usect_delayed=36000 reason=VMSCAN_THROTTLE_NOPROGRESS
148 usec_timeout=500000 usect_delayed=48000 reason=VMSCAN_THROTTLE_NOPROGRESS
159 usec_timeout=500000 usect_delayed=28000 reason=VMSCAN_THROTTLE_NOPROGRESS
178 usec_timeout=500000 usect_delayed=44000 reason=VMSCAN_THROTTLE_NOPROGRESS
183 usec_timeout=500000 usect_delayed=40000 reason=VMSCAN_THROTTLE_NOPROGRESS
237 usec_timeout=500000 usect_delayed=100000 reason=VMSCAN_THROTTLE_NOPROGRESS
266 usec_timeout=500000 usect_delayed=32000 reason=VMSCAN_THROTTLE_NOPROGRESS
313 usec_timeout=500000 usect_delayed=24000 reason=VMSCAN_THROTTLE_NOPROGRESS
347 usec_timeout=500000 usect_delayed=96000 reason=VMSCAN_THROTTLE_NOPROGRESS
470 usec_timeout=500000 usect_delayed=20000 reason=VMSCAN_THROTTLE_NOPROGRESS
559 usec_timeout=500000 usect_delayed=16000 reason=VMSCAN_THROTTLE_NOPROGRESS
964 usec_timeout=500000 usect_delayed=12000 reason=VMSCAN_THROTTLE_NOPROGRESS
2001 usec_timeout=500000 usect_delayed=104000 reason=VMSCAN_THROTTLE_NOPROGRESS
2447 usec_timeout=500000 usect_delayed=8000 reason=VMSCAN_THROTTLE_NOPROGRESS
7888 usec_timeout=500000 usect_delayed=4000 reason=VMSCAN_THROTTLE_NOPROGRESS
22727 usec_timeout=500000 usect_delayed=0 reason=VMSCAN_THROTTLE_NOPROGRESS
51305 usec_timeout=500000 usect_delayed=500000 reason=VMSCAN_THROTTLE_NOPROGRESS
The full timeout is often hit but a large number also do not stall at
all. The remainder slept a little allowing other reclaim tasks to make
progress.
While this timeout could be further increased, it could also negatively
impact worst-case behaviour when there is no prioritisation of what task
should make progress.
For VMSCAN_THROTTLE_WRITEBACK, the breakdown was
1 usec_timeout=100000 usect_delayed=44000 reason=VMSCAN_THROTTLE_WRITEBACK
2 usec_timeout=100000 usect_delayed=76000 reason=VMSCAN_THROTTLE_WRITEBACK
3 usec_timeout=100000 usect_delayed=80000 reason=VMSCAN_THROTTLE_WRITEBACK
5 usec_timeout=100000 usect_delayed=48000 reason=VMSCAN_THROTTLE_WRITEBACK
5 usec_timeout=100000 usect_delayed=84000 reason=VMSCAN_THROTTLE_WRITEBACK
6 usec_timeout=100000 usect_delayed=72000 reason=VMSCAN_THROTTLE_WRITEBACK
7 usec_timeout=100000 usect_delayed=88000 reason=VMSCAN_THROTTLE_WRITEBACK
11 usec_timeout=100000 usect_delayed=56000 reason=VMSCAN_THROTTLE_WRITEBACK
12 usec_timeout=100000 usect_delayed=64000 reason=VMSCAN_THROTTLE_WRITEBACK
16 usec_timeout=100000 usect_delayed=92000 reason=VMSCAN_THROTTLE_WRITEBACK
24 usec_timeout=100000 usect_delayed=68000 reason=VMSCAN_THROTTLE_WRITEBACK
28 usec_timeout=100000 usect_delayed=32000 reason=VMSCAN_THROTTLE_WRITEBACK
30 usec_timeout=100000 usect_delayed=60000 reason=VMSCAN_THROTTLE_WRITEBACK
30 usec_timeout=100000 usect_delayed=96000 reason=VMSCAN_THROTTLE_WRITEBACK
32 usec_timeout=100000 usect_delayed=52000 reason=VMSCAN_THROTTLE_WRITEBACK
42 usec_timeout=100000 usect_delayed=40000 reason=VMSCAN_THROTTLE_WRITEBACK
77 usec_timeout=100000 usect_delayed=28000 reason=VMSCAN_THROTTLE_WRITEBACK
99 usec_timeout=100000 usect_delayed=36000 reason=VMSCAN_THROTTLE_WRITEBACK
137 usec_timeout=100000 usect_delayed=24000 reason=VMSCAN_THROTTLE_WRITEBACK
190 usec_timeout=100000 usect_delayed=20000 reason=VMSCAN_THROTTLE_WRITEBACK
339 usec_timeout=100000 usect_delayed=16000 reason=VMSCAN_THROTTLE_WRITEBACK
518 usec_timeout=100000 usect_delayed=12000 reason=VMSCAN_THROTTLE_WRITEBACK
852 usec_timeout=100000 usect_delayed=8000 reason=VMSCAN_THROTTLE_WRITEBACK
3359 usec_timeout=100000 usect_delayed=4000 reason=VMSCAN_THROTTLE_WRITEBACK
7147 usec_timeout=100000 usect_delayed=0 reason=VMSCAN_THROTTLE_WRITEBACK
83962 usec_timeout=100000 usect_delayed=100000 reason=VMSCAN_THROTTLE_WRITEBACK
The majority hit the timeout in direct reclaim context although a
sizable number did not stall at all. This is very different to kswapd
where only a tiny percentage of stalls due to writeback reached the
timeout.
Bottom line, the throttling appears to work and the wakeup events may
limit worst case stalls. There might be some grounds for adjusting
timeouts but it's likely futile as the worst-case scenarios depend on
the workload, memory size and the speed of the storage. A better
approach to improve the series further would be to prioritise tasks
based on their rate of allocation with the caveat that it may be very
expensive to track.
This patch (of 5):
Page reclaim throttles on wait_iff_congested under the following
conditions:
- kswapd is encountering pages under writeback and marked for immediate
reclaim implying that pages are cycling through the LRU faster than
pages can be cleaned.
- Direct reclaim will stall if all dirty pages are backed by congested
inodes.
wait_iff_congested is almost completely broken with few exceptions.
This patch adds a new node-based workqueue and tracks the number of
throttled tasks and pages written back since throttling started. If
enough pages belonging to the node are written back then the throttled
tasks will wake early. If not, the throttled tasks sleeps until the
timeout expires.
[neilb@suse.de: Uninterruptible sleep and simpler wakeups]
[hdanton@sina.com: Avoid race when reclaim starts]
[vbabka@suse.cz: vmstat irq-safe api, clarifications]
Link: https://lore.kernel.org/linux-mm/45d8b7a6-8548-65f5-cccf-9f451d4ae3d4@kernel.dk/ [1]
Link: https://lkml.kernel.org/r/20211022144651.19914-1-mgorman@techsingularity.net
Link: https://lkml.kernel.org/r/20211022144651.19914-2-mgorman@techsingularity.net
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: NeilBrown <neilb@suse.de>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: "Darrick J . Wong" <djwong@kernel.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We fix the following warning when building kernel with W=1:
mm/vmscan.c:1362:6: warning: variable 'err' set but not used [-Wunused-but-set-variable]
Link: https://lkml.kernel.org/r/20210924181218.21165-1-songkai01@inspur.com
Signed-off-by: Kai Song <songkai01@inspur.com>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Isolating a free page in an isolated pageblock is expected to always
work as watermarks don't apply here.
But if __isolate_free_page() failed, due to condition changes, the page
will be left on the free list. And the page will be put back to free
list again via __putback_isolated_page(). This may trigger
VM_BUG_ON_PAGE() on page->flags checking in __free_one_page() if
PageReported is set. Or we will corrupt the free list because
list_add() will be called for pages already on another list.
Add a VM_WARN_ON() to complain about this change.
Link: https://lkml.kernel.org/r/20210914114508.23725-1-linmiaohe@huawei.com
Fixes: 3c605096d3 ("mm/page_alloc: restrict max order of merging on isolated pageblock")
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In start_isolate_page_range() undo path, pfn_to_online_page() just
checks the first pfn in a pageblock while __first_valid_page() will
traverse the pageblock until the first online pfn is found. So we may
miss the call to unset_migratetype_isolate() in undo path and pages will
remain isolated unexpectedly.
Fix this by calling undo_isolate_page_range() and this will also help to
simplify the code further. Note we shouldn't ever trigger it because
MAX_ORDER-1 aligned pfn ranges shouldn't contain memory holes now.
Link: https://lkml.kernel.org/r/20210914114348.15569-1-linmiaohe@huawei.com
Fixes: 2ce13640b3 ("mm: __first_valid_page skip over offline pages")
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In commit 7118fc2906 ("hugetlb: address ref count racing in
prep_compound_gigantic_page"), page_ref_freeze is used to atomically
zero the ref count of tail pages iff they are 1. The unconditional call
to set_page_count(0) was left in the code. This call is after
page_ref_freeze so it is really a noop.
Remove redundant and unnecessary set_page_count call.
Link: https://lkml.kernel.org/r/20211026220635.35187-1-mike.kravetz@oracle.com
Fixes: 7118fc2906 ("hugetlb: address ref count racing in prep_compound_gigantic_page")
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Suggested-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Reviewed-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When calling hugetlb_resv_map_add(), we've guaranteed that the parameter
'to' is always larger than 'from', so it never returns a negative value
from hugetlb_resv_map_add(). Thus remove the redundant VM_BUG_ON().
Link: https://lkml.kernel.org/r/2b565552f3d06753da1e8dda439c0d96d6d9a5a3.1634797639.git.baolin.wang@linux.alibaba.com
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Michal Hocko <mhocko@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The callers of has_same_uncharge_info() has accessed the original
file_region and new file_region, and they are impossible to be NULL now.
So we can remove the file_region validation in has_same_uncharge_info()
to simplify the code.
Link: https://lkml.kernel.org/r/97fc68d3f8d34f63c204645e10d7a718997e50b7.1634797639.git.baolin.wang@linux.alibaba.com
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Michal Hocko <mhocko@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
After commit 8382d914eb ("mm, hugetlb: improve page-fault
scalability"), the hugetlb_instantiation_mutex lock had been replaced by
hugetlb_fault_mutex_table to serializes faults on the same logical page.
Thus update the obsolete hugetlb_instantiation_mutex related comments.
Link: https://lkml.kernel.org/r/4b3febeae37455ff7b74aa0aad16cc6909cf0926.1634797639.git.baolin.wang@linux.alibaba.com
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Michal Hocko <mhocko@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Now the size of CMA area for gigantic hugepages runtime allocation is
balanced for all online nodes, but we also want to specify the size of
CMA per-node, or only one node in some cases, which are similar with
patch [1].
For example, on some multi-nodes systems, each node's memory can be
different, allocating the same size of CMA for each node is not suitable
for the low-memory nodes. Meanwhile some workloads like DPDK mentioned
by Zhenguo in patch [1] only need hugepages in one node.
On the other hand, we have some machines with multiple types of memory,
like DRAM and PMEM (persistent memory). On this system, we may want to
specify all the hugepages only on DRAM node, or specify the proportion
of DRAM node and PMEM node, to tuning the performance of the workloads.
Thus this patch adds node format for 'hugetlb_cma' parameter to support
specifying the size of CMA per-node. An example is as follows:
hugetlb_cma=0:5G,2:5G
which means allocating 5G size of CMA area on node 0 and node 2
respectively. And the users should use the node specific sysfs file to
allocate the gigantic hugepages if specified the CMA size on that node.
Link: https://lkml.kernel.org/r/20211005054729.86457-1-yaozhenguo1@gmail.com [1]
Link: https://lkml.kernel.org/r/bb790775ca60bb8f4b26956bb3f6988f74e075c7.1634261144.git.baolin.wang@linux.alibaba.com
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Roman Gushchin <guro@fb.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Support mremap() for hugepage backed vma segment by simply repositioning
page table entries. The page table entries are repositioned to the new
virtual address on mremap().
Hugetlb mremap() support is of course generic; my motivating use case is
a library (hugepage_text), which reloads the ELF text of executables in
hugepages. This significantly increases the execution performance of
said executables.
Restrict the mremap operation on hugepages to up to the size of the
original mapping as the underlying hugetlb reservation is not yet
capable of handling remapping to a larger size.
During the mremap() operation we detect pmd_share'd mappings and we
unshare those during the mremap(). On access and fault the sharing is
established again.
Link: https://lkml.kernel.org/r/20211013195825.3058275-1-almasrymina@google.com
Signed-off-by: Mina Almasry <almasrymina@google.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Ken Chen <kenchen@google.com>
Cc: Chris Kennelly <ckennelly@google.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Kirill Shutemov <kirill@shutemov.name>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When initializing transparent huge pages, min_free_kbytes would be
calculated according to what khugepaged expected.
So when transparent huge pages get disabled, min_free_kbytes should be
recalculated instead of the higher value set by khugepaged.
Link: https://lkml.kernel.org/r/1633937809-16558-1-git-send-email-liangcaifan19@gmail.com
Signed-off-by: Liangcai Fan <liangcaifan19@gmail.com>
Signed-off-by: Chunyan Zhang <zhang.lyra@gmail.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Demote page functionality will split a huge page into a number of huge
pages of a smaller size. For example, on x86 a 1GB huge page can be
demoted into 512 2M huge pages. Demotion is done 'in place' by simply
splitting the huge page.
Added '*_for_demote' wrappers for remove_hugetlb_page,
destroy_compound_hugetlb_page and prep_compound_gigantic_page for use by
demote code.
[mike.kravetz@oracle.com: v4]
Link: https://lkml.kernel.org/r/6ca29b8e-527c-d6ec-900e-e6a43e4f8b73@oracle.com
Link: https://lkml.kernel.org/r/20211007181918.136982-6-mike.kravetz@oracle.com
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: "Aneesh Kumar K . V" <aneesh.kumar@linux.ibm.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Naoya Horiguchi <naoya.horiguchi@linux.dev>
Cc: Nghia Le <nghialm78@gmail.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The routines remove_hugetlb_page and destroy_compound_gigantic_page will
remove a gigantic page and make the set of base pages ready to be
returned to a lower level allocator. In the process of doing this, they
make all base pages reference counted.
The routine prep_compound_gigantic_page creates a gigantic page from a
set of base pages. It assumes that all these base pages are reference
counted.
During demotion, a gigantic page will be split into huge pages of a
smaller size. This logically involves use of the routines,
remove_hugetlb_page, and destroy_compound_gigantic_page followed by
prep_compound*_page for each smaller huge page.
When pages are reference counted (ref count >= 0), additional
speculative ref counts could be taken as described in previous commits
[1] and [2]. This could result in errors while demoting a huge page.
Quite a bit of code would need to be created to handle all possible
issues.
Instead of dealing with the possibility of speculative ref counts, avoid
the possibility by keeping ref counts at zero during the demote process.
Add a boolean 'demote' to the routines remove_hugetlb_page,
destroy_compound_gigantic_page and prep_compound_gigantic_page. If the
boolean is set, the remove and destroy routines will not reference count
pages and the prep routine will not expect reference counted pages.
'*_for_demote' wrappers of the routines will be added in a subsequent
patch where this functionality is used.
[1] https://lore.kernel.org/linux-mm/20210622021423.154662-3-mike.kravetz@oracle.com/
[2] https://lore.kernel.org/linux-mm/20210809184832.18342-3-mike.kravetz@oracle.com/
Link: https://lkml.kernel.org/r/20211007181918.136982-5-mike.kravetz@oracle.com
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: "Aneesh Kumar K . V" <aneesh.kumar@linux.ibm.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Naoya Horiguchi <naoya.horiguchi@linux.dev>
Cc: Nghia Le <nghialm78@gmail.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When huge page demotion is fully implemented, gigantic pages can be
demoted to a smaller huge page size. For example, on x86 a 1G page can
be demoted to 512 2M pages. However, gigantic pages can potentially be
allocated from CMA. If a gigantic page which was allocated from CMA is
demoted, the corresponding demoted pages needs to be returned to CMA.
Use the new interface cma_pages_valid() to determine if a non-gigantic
hugetlb page should be freed to CMA. Also, clear mapping field of these
pages as expected by cma_release.
This also requires a change to CMA region creation for gigantic pages.
CMA uses a per-region bit map to track allocations. When setting up the
region, you specify how many pages each bit represents. Currently, only
gigantic pages are allocated/freed from CMA so the region is set up such
that one bit represents a gigantic page size allocation.
With demote, a gigantic page (allocation) could be split into smaller
size pages. And, these smaller size pages will be freed to CMA. So,
since the per-region bit map needs to be set up to represent the
smallest allocation/free size, it now needs to be set to the smallest
huge page size which can be freed to CMA.
Unfortunately, we set up the CMA region for huge pages before we set up
huge pages sizes (hstates). So, technically we do not know the smallest
huge page size as this can change via command line options and
architecture specific code. Therefore, at region setup time we use
HUGETLB_PAGE_ORDER as the smallest possible huge page size that can be
given back to CMA. It is possible that this value is sub-optimal for
some architectures/config options. If needed, this can be addressed in
follow on work.
Link: https://lkml.kernel.org/r/20211007181918.136982-4-mike.kravetz@oracle.com
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: "Aneesh Kumar K . V" <aneesh.kumar@linux.ibm.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Naoya Horiguchi <naoya.horiguchi@linux.dev>
Cc: Nghia Le <nghialm78@gmail.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add new interface cma_pages_valid() which indicates if the specified
pages are part of a CMA region. This interface will be used in a
subsequent patch by hugetlb code.
In order to keep the same amount of DEBUG information, a pr_debug() call
was added to cma_pages_valid(). In the case where the page passed to
cma_release is not in cma region, the debug message will be printed from
cma_pages_valid as opposed to cma_release.
Link: https://lkml.kernel.org/r/20211007181918.136982-3-mike.kravetz@oracle.com
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: "Aneesh Kumar K . V" <aneesh.kumar@linux.ibm.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Naoya Horiguchi <naoya.horiguchi@linux.dev>
Cc: Nghia Le <nghialm78@gmail.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "hugetlb: add demote/split page functionality", v4.
The concurrent use of multiple hugetlb page sizes on a single system is
becoming more common. One of the reasons is better TLB support for
gigantic page sizes on x86 hardware. In addition, hugetlb pages are
being used to back VMs in hosting environments.
When using hugetlb pages to back VMs, it is often desirable to
preallocate hugetlb pools. This avoids the delay and uncertainty of
allocating hugetlb pages at VM startup. In addition, preallocating huge
pages minimizes the issue of memory fragmentation that increases the
longer the system is up and running.
In such environments, a combination of larger and smaller hugetlb pages
are preallocated in anticipation of backing VMs of various sizes. Over
time, the preallocated pool of smaller hugetlb pages may become depleted
while larger hugetlb pages still remain. In such situations, it is
desirable to convert larger hugetlb pages to smaller hugetlb pages.
Converting larger to smaller hugetlb pages can be accomplished today by
first freeing the larger page to the buddy allocator and then allocating
the smaller pages. For example, to convert 50 GB pages on x86:
gb_pages=`cat .../hugepages-1048576kB/nr_hugepages`
m2_pages=`cat .../hugepages-2048kB/nr_hugepages`
echo $(($gb_pages - 50)) > .../hugepages-1048576kB/nr_hugepages
echo $(($m2_pages + 25600)) > .../hugepages-2048kB/nr_hugepages
On an idle system this operation is fairly reliable and results are as
expected. The number of 2MB pages is increased as expected and the time
of the operation is a second or two.
However, when there is activity on the system the following issues
arise:
1) This process can take quite some time, especially if allocation of
the smaller pages is not immediate and requires migration/compaction.
2) There is no guarantee that the total size of smaller pages allocated
will match the size of the larger page which was freed. This is
because the area freed by the larger page could quickly be
fragmented.
In a test environment with a load that continually fills the page cache
with clean pages, results such as the following can be observed:
Unexpected number of 2MB pages allocated: Expected 25600, have 19944
real 0m42.092s
user 0m0.008s
sys 0m41.467s
To address these issues, introduce the concept of hugetlb page demotion.
Demotion provides a means of 'in place' splitting of a hugetlb page to
pages of a smaller size. This avoids freeing pages to buddy and then
trying to allocate from buddy.
Page demotion is controlled via sysfs files that reside in the per-hugetlb
page size and per node directories.
- demote_size
Target page size for demotion, a smaller huge page size. File
can be written to chose a smaller huge page size if multiple are
available.
- demote
Writable number of hugetlb pages to be demoted
To demote 50 GB huge pages, one would:
cat .../hugepages-1048576kB/free_hugepages /* optional, verify free pages */
cat .../hugepages-1048576kB/demote_size /* optional, verify target size */
echo 50 > .../hugepages-1048576kB/demote
Only hugetlb pages which are free at the time of the request can be
demoted. Demotion does not add to the complexity of surplus pages and
honors reserved huge pages. Therefore, when a value is written to the
sysfs demote file, that value is only the maximum number of pages which
will be demoted. It is possible fewer will actually be demoted. The
recently introduced per-hstate mutex is used to synchronize demote
operations with other operations that modify hugetlb pools.
Real world use cases
--------------------
The above scenario describes a real world use case where hugetlb pages
are used to back VMs on x86. Both issues of long allocation times and
not necessarily getting the expected number of smaller huge pages after
a free and allocate cycle have been experienced. The occurrence of
these issues is dependent on other activity within the host and can not
be predicted.
This patch (of 5):
Two new sysfs files are added to demote hugtlb pages. These files are
both per-hugetlb page size and per node. Files are:
demote_size - The size in Kb that pages are demoted to. (read-write)
demote - The number of huge pages to demote. (write-only)
By default, demote_size is the next smallest huge page size. Valid huge
page sizes less than huge page size may be written to this file. When
huge pages are demoted, they are demoted to this size.
Writing a value to demote will result in an attempt to demote that
number of hugetlb pages to an appropriate number of demote_size pages.
NOTE: Demote interfaces are only provided for huge page sizes if there
is a smaller target demote huge page size. For example, on x86 1GB huge
pages will have demote interfaces. 2MB huge pages will not have demote
interfaces.
This patch does not provide full demote functionality. It only provides
the sysfs interfaces.
It also provides documentation for the new interfaces.
[mike.kravetz@oracle.com: n_mask initialization does not need to be protected by the mutex]
Link: https://lkml.kernel.org/r/0530e4ef-2492-5186-f919-5db68edea654@oracle.com
Link: https://lkml.kernel.org/r/20211007181918.136982-2-mike.kravetz@oracle.com
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: David Hildenbrand <david@redhat.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Naoya Horiguchi <naoya.horiguchi@linux.dev>
Cc: David Rientjes <rientjes@google.com>
Cc: "Aneesh Kumar K . V" <aneesh.kumar@linux.ibm.com>
Cc: Nghia Le <nghialm78@gmail.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Remove __unmap_hugepage_range() from the header file, because it is only
used in hugetlb.c.
Link: https://lkml.kernel.org/r/20210917165108.9341-1-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Suggested-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently hwpoison doesn't handle non-anonymous THP, but since v4.8 THP
support for tmpfs and read-only file cache has been added. They could
be offlined by split THP, just like anonymous THP.
Link: https://lkml.kernel.org/r/20211020210755.23964-7-shy828301@gmail.com
Signed-off-by: Yang Shi <shy828301@gmail.com>
Acked-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Peter Xu <peterx@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The current behavior of memory failure is to truncate the page cache
regardless of dirty or clean. If the page is dirty the later access
will get the obsolete data from disk without any notification to the
users. This may cause silent data loss. It is even worse for shmem
since shmem is in-memory filesystem, truncating page cache means
discarding data blocks. The later read would return all zero.
The right approach is to keep the corrupted page in page cache, any
later access would return error for syscalls or SIGBUS for page fault,
until the file is truncated, hole punched or removed. The regular
storage backed filesystems would be more complicated so this patch is
focused on shmem. This also unblock the support for soft offlining
shmem THP.
[arnd@arndb.de: fix uninitialized variable use in me_pagecache_clean()]
Link: https://lkml.kernel.org/r/20211022064748.4173718-1-arnd@kernel.org
Link: https://lkml.kernel.org/r/20211020210755.23964-6-shy828301@gmail.com
Signed-off-by: Yang Shi <shy828301@gmail.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Hugh Dickins <hughd@google.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Peter Xu <peterx@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Memory failure will report failure if the page still has extra pinned
refcount other than from hwpoison after the handler is done. Actually
the check is not necessary for all handlers, so move the check into
specific handlers. This would make the following keeping shmem page in
page cache patch easier.
There may be expected extra pin for some cases, for example, when the
page is dirty and in swapcache.
Link: https://lkml.kernel.org/r/20211020210755.23964-5-shy828301@gmail.com
Signed-off-by: Yang Shi <shy828301@gmail.com>
Signed-off-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Suggested-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Peter Xu <peterx@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "Solve silent data loss caused by poisoned page cache (shmem/tmpfs)", v5.
When discussing the patch that splits page cache THP in order to offline
the poisoned page, Noaya mentioned there is a bigger problem [1] that
prevents this from working since the page cache page will be truncated
if uncorrectable errors happen. By looking this deeper it turns out
this approach (truncating poisoned page) may incur silent data loss for
all non-readonly filesystems if the page is dirty. It may be worse for
in-memory filesystem, e.g. shmem/tmpfs since the data blocks are
actually gone.
To solve this problem we could keep the poisoned dirty page in page
cache then notify the users on any later access, e.g. page fault,
read/write, etc. The clean page could be truncated as is since they can
be reread from disk later on.
The consequence is the filesystems may find poisoned page and manipulate
it as healthy page since all the filesystems actually don't check if the
page is poisoned or not in all the relevant paths except page fault. In
general, we need make the filesystems be aware of poisoned page before
we could keep the poisoned page in page cache in order to solve the data
loss problem.
To make filesystems be aware of poisoned page we should consider:
- The page should be not written back: clearing dirty flag could
prevent from writeback.
- The page should not be dropped (it shows as a clean page) by drop
caches or other callers: the refcount pin from hwpoison could prevent
from invalidating (called by cache drop, inode cache shrinking, etc),
but it doesn't avoid invalidation in DIO path.
- The page should be able to get truncated/hole punched/unlinked: it
works as it is.
- Notify users when the page is accessed, e.g. read/write, page fault
and other paths (compression, encryption, etc).
The scope of the last one is huge since almost all filesystems need do
it once a page is returned from page cache lookup. There are a couple
of options to do it:
1. Check hwpoison flag for every path, the most straightforward way.
2. Return NULL for poisoned page from page cache lookup, the most
callsites check if NULL is returned, this should have least work I
think. But the error handling in filesystems just return -ENOMEM,
the error code will incur confusion to the users obviously.
3. To improve #2, we could return error pointer, e.g. ERR_PTR(-EIO),
but this will involve significant amount of code change as well
since all the paths need check if the pointer is ERR or not just
like option #1.
I did prototypes for both #1 and #3, but it seems #3 may require more
changes than #1. For #3 ERR_PTR will be returned so all the callers
need to check the return value otherwise invalid pointer may be
dereferenced, but not all callers really care about the content of the
page, for example, partial truncate which just sets the truncated range
in one page to 0. So for such paths it needs additional modification if
ERR_PTR is returned. And if the callers have their own way to handle
the problematic pages we need to add a new FGP flag to tell FGP
functions to return the pointer to the page.
It may happen very rarely, but once it happens the consequence (data
corruption) could be very bad and it is very hard to debug. It seems
this problem had been slightly discussed before, but seems no action was
taken at that time. [2]
As the aforementioned investigation, it needs huge amount of work to
solve the potential data loss for all filesystems. But it is much
easier for in-memory filesystems and such filesystems actually suffer
more than others since even the data blocks are gone due to truncating.
So this patchset starts from shmem/tmpfs by taking option #1.
TODO:
* The unpoison has been broken since commit 0ed950d1f2 ("mm,hwpoison: make
get_hwpoison_page() call get_any_page()"), and this patch series make
refcount check for unpoisoning shmem page fail.
* Expand to other filesystems. But I haven't heard feedback from filesystem
developers yet.
Patch breakdown:
Patch #1: cleanup, depended by patch #2
Patch #2: fix THP with hwpoisoned subpage(s) PMD map bug
Patch #3: coding style cleanup
Patch #4: refactor and preparation.
Patch #5: keep the poisoned page in page cache and handle such case for all
the paths.
Patch #6: the previous patches unblock page cache THP split, so this patch
add page cache THP split support.
This patch (of 4):
A minor cleanup to the indent.
Link: https://lkml.kernel.org/r/20211020210755.23964-1-shy828301@gmail.com
Link: https://lkml.kernel.org/r/20211020210755.23964-4-shy828301@gmail.com
Signed-off-by: Yang Shi <shy828301@gmail.com>
Reviewed-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Peter Xu <peterx@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The only usage of hwp_walk_ops is to pass its address to
walk_page_range() which takes a pointer to const mm_walk_ops as
argument.
Make it const to allow the compiler to put it in read-only memory.
Link: https://lkml.kernel.org/r/20211014075042.17174-3-rikard.falkeborn@gmail.com
Signed-off-by: Rikard Falkeborn <rikard.falkeborn@gmail.com>
Acked-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch uses clamp() to simplify code in init_per_zone_wmark_min().
Link: https://lkml.kernel.org/r/20211021034830.1049150-1-bobo.shaobowang@huawei.com
Signed-off-by: Wang ShaoBo <bobo.shaobowang@huawei.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Wei Yongjun <weiyongjun1@huawei.com>
Cc: Li Bin <huawei.libin@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
drain_local_pages_wq() disables preemption to avoid CPU migration during
CPU hotplug and can't use cpus_read_lock().
Using migrate_disable() works here, too. The scheduler won't take the
CPU offline until the task left the migrate-disable section. The
problem with disabled preemption here is that drain_local_pages()
acquires locks which are turned into sleeping locks on PREEMPT_RT and
can't be acquired with disabled preemption.
Use migrate_disable() in drain_local_pages_wq().
Link: https://lkml.kernel.org/r/20211015210933.viw6rjvo64qtqxn4@linutronix.de
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
min/low/high_wmark_pages(z) is defined as
(z->_watermark[WMARK_MIN/LOW/HIGH] + z->watermark_boost)
If kswapd is frequently woken up due to the increase of
min/low/high_wmark_pages, printing watermark_boost can quickly locate
whether watermark_boost or _watermark[WMARK_MIN/LOW/HIGH] caused
min/low/high_wmark_pages to increase.
Link: https://lkml.kernel.org/r/1632472566-12246-1-git-send-email-liangcaifan19@gmail.com
Signed-off-by: Liangcai Fan <liangcaifan19@gmail.com>
Cc: Chunyan Zhang <zhang.lyra@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There was a report that starting an Ubuntu in docker while using cpuset
to bind it to movable nodes (a node only has movable zone, like a node
for hotplug or a Persistent Memory node in normal usage) will fail due
to memory allocation failure, and then OOM is involved and many other
innocent processes got killed.
It can be reproduced with command:
$ docker run -it --rm --cpuset-mems 4 ubuntu:latest bash -c "grep Mems_allowed /proc/self/status"
(where node 4 is a movable node)
runc:[2:INIT] invoked oom-killer: gfp_mask=0x500cc2(GFP_HIGHUSER|__GFP_ACCOUNT), order=0, oom_score_adj=0
CPU: 8 PID: 8291 Comm: runc:[2:INIT] Tainted: G W I E 5.8.2-0.g71b519a-default #1 openSUSE Tumbleweed (unreleased)
Hardware name: Dell Inc. PowerEdge R640/0PHYDR, BIOS 2.6.4 04/09/2020
Call Trace:
dump_stack+0x6b/0x88
dump_header+0x4a/0x1e2
oom_kill_process.cold+0xb/0x10
out_of_memory.part.0+0xaf/0x230
out_of_memory+0x3d/0x80
__alloc_pages_slowpath.constprop.0+0x954/0xa20
__alloc_pages_nodemask+0x2d3/0x300
pipe_write+0x322/0x590
new_sync_write+0x196/0x1b0
vfs_write+0x1c3/0x1f0
ksys_write+0xa7/0xe0
do_syscall_64+0x52/0xd0
entry_SYSCALL_64_after_hwframe+0x44/0xa9
Mem-Info:
active_anon:392832 inactive_anon:182 isolated_anon:0
active_file:68130 inactive_file:151527 isolated_file:0
unevictable:2701 dirty:0 writeback:7
slab_reclaimable:51418 slab_unreclaimable:116300
mapped:45825 shmem:735 pagetables:2540 bounce:0
free:159849484 free_pcp:73 free_cma:0
Node 4 active_anon:1448kB inactive_anon:0kB active_file:0kB inactive_file:0kB unevictable:0kB isolated(anon):0kB isolated(file):0kB mapped:0kB dirty:0kB writeback:0kB shmem:0kB shmem_thp: 0kB shmem_pmdmapped: 0kB anon_thp: 0kB writeback_tmp:0kB all_unreclaimable? no
Node 4 Movable free:130021408kB min:9140kB low:139160kB high:269180kB reserved_highatomic:0KB active_anon:1448kB inactive_anon:0kB active_file:0kB inactive_file:0kB unevictable:0kB writepending:0kB present:130023424kB managed:130023424kB mlocked:0kB kernel_stack:0kB pagetables:0kB bounce:0kB free_pcp:292kB local_pcp:84kB free_cma:0kB
lowmem_reserve[]: 0 0 0 0 0
Node 4 Movable: 1*4kB (M) 0*8kB 0*16kB 1*32kB (M) 0*64kB 0*128kB 1*256kB (M) 1*512kB (M) 1*1024kB (M) 0*2048kB 31743*4096kB (M) = 130021156kB
oom-kill:constraint=CONSTRAINT_CPUSET,nodemask=(null),cpuset=docker-9976a269caec812c134fa317f27487ee36e1129beba7278a463dd53e5fb9997b.scope,mems_allowed=4,global_oom,task_memcg=/system.slice/containerd.service,task=containerd,pid=4100,uid=0
Out of memory: Killed process 4100 (containerd) total-vm:4077036kB, anon-rss:51184kB, file-rss:26016kB, shmem-rss:0kB, UID:0 pgtables:676kB oom_score_adj:0
oom_reaper: reaped process 8248 (docker), now anon-rss:0kB, file-rss:0kB, shmem-rss:0kB
oom_reaper: reaped process 2054 (node_exporter), now anon-rss:0kB, file-rss:0kB, shmem-rss:0kB
oom_reaper: reaped process 1452 (systemd-journal), now anon-rss:0kB, file-rss:8564kB, shmem-rss:4kB
oom_reaper: reaped process 2146 (munin-node), now anon-rss:0kB, file-rss:0kB, shmem-rss:0kB
oom_reaper: reaped process 8291 (runc:[2:INIT]), now anon-rss:0kB, file-rss:0kB, shmem-rss:0kB
The reason is that in this case, the target cpuset nodes only have
movable zone, while the creation of an OS in docker sometimes needs to
allocate memory in non-movable zones (dma/dma32/normal) like
GFP_HIGHUSER, and the cpuset limit forbids the allocation, then
out-of-memory killing is involved even when normal nodes and movable
nodes both have many free memory.
The OOM killer cannot help to resolve the situation as there is no
usable memory for the request in the cpuset scope. The only reasonable
measure to take is to fail the allocation right away and have the caller
to deal with it.
So add a check for cases like this in the slowpath of allocation, and
bail out early returning NULL for the allocation.
As page allocation is one of the hottest path in kernel, this check will
hurt all users with sane cpuset configuration, add a static branch check
and detect the abnormal config in cpuset memory binding setup so that
the extra check cost in page allocation is not paid by everyone.
[thanks to Micho Hocko and David Rientjes for suggesting not handling
it inside OOM code, adding cpuset check, refining comments]
Link: https://lkml.kernel.org/r/1632481657-68112-1-git-send-email-feng.tang@intel.com
Signed-off-by: Feng Tang <feng.tang@intel.com>
Suggested-by: Michal Hocko <mhocko@suse.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Zefan Li <lizefan.x@bytedance.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Grabbing zone lock in is_free_buddy_page() gives a wrong sense of
safety, and has potential performance implications when zone is
experiencing lock contention.
In any case, if a caller needs a stable result, it should grab zone lock
before calling this function.
Link: https://lkml.kernel.org/r/20210922152833.4023972-1-eric.dumazet@gmail.com
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
If CONFIG_NUMA=y, but CONFIG_SMP=n (e.g. sh/migor_defconfig):
sh4-linux-gnu-ld: mm/vmstat.o: in function `vmstat_start': vmstat.c:(.text+0x97c): undefined reference to `fold_vm_numa_events'
sh4-linux-gnu-ld: drivers/base/node.o: in function `node_read_vmstat': node.c:(.text+0x140): undefined reference to `fold_vm_numa_events'
sh4-linux-gnu-ld: drivers/base/node.o: in function `node_read_numastat': node.c:(.text+0x1d0): undefined reference to `fold_vm_numa_events'
Fix this by moving fold_vm_numa_events() outside the SMP-only section.
Link: https://lkml.kernel.org/r/9d16ccdd9ef32803d7100c84f737de6a749314fb.1631781495.git.geert+renesas@glider.be
Fixes: f19298b951 ("mm/vmstat: convert NUMA statistics to basic NUMA counters")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Mel Gorman <mgorman@suse.de>
Cc: Gon Solo <gonsolo@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rich Felker <dalias@libc.org>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yoshinori Sato <ysato@users.osdn.me>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "Fix NUMA without SMP".
SuperH is the only architecture which still supports NUMA without SMP,
for good reasons (various memories scattered around the address space,
each with varying latencies).
This series fixes two build errors due to variables and functions used
by the NUMA code being provided by SMP-only source files or sections.
This patch (of 2):
If CONFIG_NUMA=y, but CONFIG_SMP=n (e.g. sh/migor_defconfig):
sh4-linux-gnu-ld: mm/page_alloc.o: in function `get_page_from_freelist':
page_alloc.c:(.text+0x2c24): undefined reference to `node_reclaim_distance'
Fix this by moving the declaration of node_reclaim_distance from an
SMP-only to a generic file.
Link: https://lkml.kernel.org/r/cover.1631781495.git.geert+renesas@glider.be
Link: https://lkml.kernel.org/r/6432666a648dde85635341e6c918cee97c97d264.1631781495.git.geert+renesas@glider.be
Fixes: a55c7454a8 ("sched/topology: Improve load balancing on AMD EPYC systems")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Suggested-by: Matt Fleming <matt@codeblueprint.co.uk>
Acked-by: Mel Gorman <mgorman@suse.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yoshinori Sato <ysato@users.osdn.me>
Cc: Rich Felker <dalias@libc.org>
Cc: Gon Solo <gonsolo@gmail.com>
Cc: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In build_zonelists(), when the fallback list is built for the nodes, the
node load gets reinitialized during each iteration. This results in
nodes with same distances occupying the same slot in different node
fallback lists rather than appearing in the intended round- robin
manner. This results in one node getting picked for allocation more
compared to other nodes with the same distance.
As an example, consider a 4 node system with the following distance
matrix.
Node 0 1 2 3
----------------
0 10 12 32 32
1 12 10 32 32
2 32 32 10 12
3 32 32 12 10
For this case, the node fallback list gets built like this:
Node Fallback list
---------------------
0 0 1 2 3
1 1 0 3 2
2 2 3 0 1
3 3 2 0 1 <-- Unexpected fallback order
In the fallback list for nodes 2 and 3, the nodes 0 and 1 appear in the
same order which results in more allocations getting satisfied from node
0 compared to node 1.
The effect of this on remote memory bandwidth as seen by stream
benchmark is shown below:
Case 1: Bandwidth from cores on nodes 2 & 3 to memory on nodes 0 & 1
(numactl -m 0,1 ./stream_lowOverhead ... --cores <from 2, 3>)
Case 2: Bandwidth from cores on nodes 0 & 1 to memory on nodes 2 & 3
(numactl -m 2,3 ./stream_lowOverhead ... --cores <from 0, 1>)
----------------------------------------
BANDWIDTH (MB/s)
TEST Case 1 Case 2
----------------------------------------
COPY 57479.6 110791.8
SCALE 55372.9 105685.9
ADD 50460.6 96734.2
TRIADD 50397.6 97119.1
----------------------------------------
The bandwidth drop in Case 1 occurs because most of the allocations get
satisfied by node 0 as it appears first in the fallback order for both
nodes 2 and 3.
This can be fixed by accumulating the node load in build_zonelists()
rather than reinitializing it during each iteration. With this the
nodes with the same distance rightly get assigned in the round robin
manner.
In fact this was how it was originally until commit f0c0b2b808
("change zonelist order: zonelist order selection logic") dropped the
load accumulation and resorted to initializing the load during each
iteration.
While zonelist ordering was removed by commit c9bff3eebc ("mm,
page_alloc: rip out ZONELIST_ORDER_ZONE"), the change to the node load
accumulation in build_zonelists() remained. So essentially this patch
reverts back to the accumulated node load logic.
After this fix, the fallback order gets built like this:
Node Fallback list
------------------
0 0 1 2 3
1 1 0 3 2
2 2 3 0 1
3 3 2 1 0 <-- Note the change here
The bandwidth in Case 1 improves and matches Case 2 as shown below.
----------------------------------------
BANDWIDTH (MB/s)
TEST Case 1 Case 2
----------------------------------------
COPY 110438.9 110107.2
SCALE 105930.5 105817.5
ADD 97005.1 96159.8
TRIADD 97441.5 96757.1
----------------------------------------
The correctness of the fallback list generation has been verified for
the above node configuration where the node 3 starts as memory-less node
and comes up online only during memory hotplug.
[bharata@amd.com: Added changelog, review, test validation]
Link: https://lkml.kernel.org/r/20210830121603.1081-3-bharata@amd.com
Fixes: f0c0b2b808 ("change zonelist order: zonelist order selection logic")
Signed-off-by: Krupa Ramakrishnan <krupa.ramakrishnan@amd.com>
Co-developed-by: Sadagopan Srinivasan <Sadagopan.Srinivasan@amd.com>
Signed-off-by: Sadagopan Srinivasan <Sadagopan.Srinivasan@amd.com>
Signed-off-by: Bharata B Rao <bharata@amd.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "Fix NUMA nodes fallback list ordering".
For a NUMA system that has multiple nodes at same distance from other
nodes, the fallback list generation prefers same node order for them
instead of round-robin thereby penalizing one node over others. This
series fixes it.
More description of the problem and the fix is present in the patch
description.
This patch (of 2):
Print information message about the allocation fallback order for each
NUMA node during boot.
No functional changes here. This makes it easier to illustrate the
problem in the node fallback list generation, which the next patch
fixes.
Link: https://lkml.kernel.org/r/20210830121603.1081-1-bharata@amd.com
Link: https://lkml.kernel.org/r/20210830121603.1081-2-bharata@amd.com
Signed-off-by: Bharata B Rao <bharata@amd.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Krupa Ramakrishnan <krupa.ramakrishnan@amd.com>
Cc: Sadagopan Srinivasan <Sadagopan.Srinivasan@amd.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Don't use with __GFP_HIGHMEM because page_address() cannot represent
highmem pages without kmap(). Newly allocated pages would leak as
page_address() will return NULL for highmem pages here. But It works
now because the callers do not specify __GFP_HIGHMEM now.
Link: https://lkml.kernel.org/r/20210902121242.41607-6-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Use helper function zone_spans_pfn() to check whether pfn is within a
zone to simplify the code slightly.
Link: https://lkml.kernel.org/r/20210902121242.41607-5-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The second two paragraphs about "all pages pinned" and pages_scanned is
obsolete. And There are PAGE_ALLOC_COSTLY_ORDER + 1 + NR_PCP_THP orders
in pcp. So the same order assumption is not held now.
Link: https://lkml.kernel.org/r/20210902121242.41607-4-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Cc: David Hildenbrand <david@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Use helper macro K() to convert the pages to the corresponding size.
Minor readability improvement.
Link: https://lkml.kernel.org/r/20210902121242.41607-3-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "Cleanups and fixup for page_alloc", v2.
This series contains cleanups to remove meaningless VM_BUG_ON(), use
helpers to simplify the code and remove obsolete comment. Also we avoid
allocating highmem pages via alloc_pages_exact[_nid]. More details can be
found in the respective changelogs.
This patch (of 5):
It's meaningless to VM_BUG_ON() order != pageblock_order just after
setting order to pageblock_order. Remove it.
Link: https://lkml.kernel.org/r/20210902121242.41607-1-linmiaohe@huawei.com
Link: https://lkml.kernel.org/r/20210902121242.41607-2-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
If __vmalloc() returned NULL, is_vm_area_hugepages(NULL) will fault if
CONFIG_HAVE_ARCH_HUGE_VMALLOC=y
Link: https://lkml.kernel.org/r/20210915212530.2321545-1-eric.dumazet@gmail.com
Fixes: 121e6f3258 ("mm/vmalloc: hugepage vmalloc mappings")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit ffb29b1c25 ("mm/vmalloc: fix numa spreading for large hash
tables") can cause significant performance regressions in some
situations as Andrew mentioned in [1]. The main situation is vmalloc,
vmalloc will allocate pages with NUMA_NO_NODE by default, that will
result in alloc page one by one;
In order to solve this, __alloc_pages_bulk and mempolicy should be
considered at the same time.
1) If node is specified in memory allocation request, it will alloc all
pages by __alloc_pages_bulk.
2) If interleaving allocate memory, it will cauculate how many pages
should be allocated in each node, and use __alloc_pages_bulk to alloc
pages in each node.
[1]: https://lore.kernel.org/lkml/CALvZod4G3SzP3kWxQYn0fj+VgG-G3yWXz=gz17+3N57ru1iajw@mail.gmail.com/t/#m750c8e3231206134293b089feaa090590afa0f60
[akpm@linux-foundation.org: coding style fixes]
[akpm@linux-foundation.org: make two functions static]
[akpm@linux-foundation.org: fix CONFIG_NUMA=n build]
Link: https://lkml.kernel.org/r/20211021080744.874701-3-chenwandun@huawei.com
Signed-off-by: Chen Wandun <chenwandun@huawei.com>
Reviewed-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Hanjun Guo <guohanjun@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The core of the vmalloc allocator __vmalloc_area_node doesn't say
anything about gfp mask argument. Not all gfp flags are supported
though. Be more explicit about constraints.
Link: https://lkml.kernel.org/r/20211020082545.4830-1-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Neil Brown <neilb@suse.de>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Uladzislau Rezki <urezki@gmail.com>
Cc: Ilya Dryomov <idryomov@gmail.com>
Cc: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Percpu embedded first chunk allocator is the firstly option, but it
could fail on ARM64, eg,
percpu: max_distance=0x5fcfdc640000 too large for vmalloc space 0x781fefff0000
percpu: max_distance=0x600000540000 too large for vmalloc space 0x7dffb7ff0000
percpu: max_distance=0x5fff9adb0000 too large for vmalloc space 0x5dffb7ff0000
then we could get to
WARNING: CPU: 15 PID: 461 at vmalloc.c:3087 pcpu_get_vm_areas+0x488/0x838
and the system cannot boot successfully.
Let's implement page mapping percpu first chunk allocator as a fallback
to the embedding allocator to increase the robustness of the system.
Also fix a crash when both NEED_PER_CPU_PAGE_FIRST_CHUNK and
KASAN_VMALLOC enabled.
Tested on ARM64 qemu with cmdline "percpu_alloc=page".
This patch (of 3):
There are some fixed locations in the vmalloc area be reserved in
ARM(see iotable_init()) and ARM64(see map_kernel()), but for
pcpu_page_first_chunk(), it calls vm_area_register_early() and choose
VMALLOC_START as the start address of vmap area which could be
conflicted with above address, then could trigger a BUG_ON in
vm_area_add_early().
Let's choose a suit start address by traversing the vmlist.
Link: https://lkml.kernel.org/r/20210910053354.26721-1-wangkefeng.wang@huawei.com
Link: https://lkml.kernel.org/r/20210910053354.26721-2-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Marco Elver <elver@google.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Huge vmalloc allocation on heavy loaded node can lead to a global memory
shortage. Task called vmalloc can have worst badness and be selected by
OOM-killer, however taken fatal signal does not interrupt allocation
cycle. Vmalloc repeat page allocaions again and again, exacerbating the
crisis and consuming the memory freed up by another killed tasks.
After a successful completion of the allocation procedure, a fatal
signal will be processed and task will be destroyed finally. However it
may not release the consumed memory, since the allocated object may have
a lifetime unrelated to the completed task. In the worst case, this can
lead to the host will panic due to "Out of memory and no killable
processes..."
This patch allows OOM-killer to break vmalloc cycle, makes OOM more
effective and avoid host panic. It does not check oom condition
directly, however, and breaks page allocation cycle when fatal signal
was received.
This may trigger some hidden problems, when caller does not handle
vmalloc failures, or when rollaback after failed vmalloc calls own
vmallocs inside. However all of these scenarios are incorrect: vmalloc
does not guarantee successful allocation, it has never been called with
__GFP_NOFAIL and threfore either should not be used for any rollbacks or
should handle such errors correctly and not lead to critical failures.
Link: https://lkml.kernel.org/r/83efc664-3a65-2adb-d7c4-2885784cf109@virtuozzo.com
Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Cc: Uladzislau Rezki (Sony) <urezki@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Before we did not guarantee a free block with lowest start address for
allocations with alignment >= PAGE_SIZE. Because an alignment overhead
was included into a search length like below:
length = size + align - 1;
doing so we make sure that a bigger block would fit after applying an
alignment adjustment. Now there is no such limitation, i.e. any
alignment that user wants to apply will result to a lowest address of
returned free area.
Link: https://lkml.kernel.org/r/20211004142829.22222-2-urezki@gmail.com
Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hillf Danton <hdanton@sina.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Oleksiy Avramchenko <oleksiy.avramchenko@sonymobile.com>
Cc: Ping Fang <pifang@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We used to include an alignment overhead into a search length, in that
case we guarantee that a found area will definitely fit after applying a
specific alignment that user specifies. From the other hand we do not
guarantee that an area has the lowest address if an alignment is >=
PAGE_SIZE.
It means that, when a user specifies a special alignment together with a
range that corresponds to an exact requested size then an allocation
will fail. This is what happens to KASAN, it wants the free block that
exactly matches a specified range during onlining memory banks:
[root@vm-0 fedora]# echo online > /sys/devices/system/memory/memory82/state
[root@vm-0 fedora]# echo online > /sys/devices/system/memory/memory83/state
[root@vm-0 fedora]# echo online > /sys/devices/system/memory/memory85/state
[root@vm-0 fedora]# echo online > /sys/devices/system/memory/memory84/state
vmap allocation for size 16777216 failed: use vmalloc=<size> to increase size
bash: vmalloc: allocation failure: 16777216 bytes, mode:0x6000c0(GFP_KERNEL), nodemask=(null),cpuset=/,mems_allowed=0
CPU: 4 PID: 1644 Comm: bash Kdump: loaded Not tainted 4.18.0-339.el8.x86_64+debug #1
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014
Call Trace:
dump_stack+0x8e/0xd0
warn_alloc.cold.90+0x8a/0x1b2
? zone_watermark_ok_safe+0x300/0x300
? slab_free_freelist_hook+0x85/0x1a0
? __get_vm_area_node+0x240/0x2c0
? kfree+0xdd/0x570
? kmem_cache_alloc_node_trace+0x157/0x230
? notifier_call_chain+0x90/0x160
__vmalloc_node_range+0x465/0x840
? mark_held_locks+0xb7/0x120
Fix it by making sure that find_vmap_lowest_match() returns lowest start
address with any given alignment value, i.e. for alignments bigger then
PAGE_SIZE the algorithm rolls back toward parent nodes checking right
sub-trees if the most left free block did not fit due to alignment
overhead.
Link: https://lkml.kernel.org/r/20211004142829.22222-1-urezki@gmail.com
Fixes: 68ad4a3304 ("mm/vmalloc.c: keep track of free blocks for vmap allocation")
Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Reported-by: Ping Fang <pifang@redhat.com>
Tested-by: David Hildenbrand <david@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Hillf Danton <hdanton@sina.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Oleksiy Avramchenko <oleksiy.avramchenko@sonymobile.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
If last va found in vmap_area_list does not have a vm pointer,
vmallocinfo.s_show() returns 0, and show_purge_info() is not called as
it should.
Link: https://lkml.kernel.org/r/20211001170815.73321-1-eric.dumazet@gmail.com
Fixes: dd3b8353ba ("mm/vmalloc: do not keep unpurged areas in the busy tree")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Uladzislau Rezki (Sony) <urezki@gmail.com>
Cc: Pengfei Li <lpf.vector@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
show_numa_info() can be slightly faster, by skipping over hugepages
directly.
Link: https://lkml.kernel.org/r/20211001172725.105824-1-eric.dumazet@gmail.com
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Uladzislau Rezki (Sony) <urezki@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The vmalloc guard pages are added on top of each allocation, thereby
isolating any two allocations from one another. The top guard of the
lower allocation is the bottom guard guard of the higher allocation etc.
Therefore VM_NO_GUARD is dangerous; it breaks the basic premise of
isolating separate allocations.
There are only two in-tree users of this flag, neither of which use it
through the exported interface. Ensure it stays this way.
Link: https://lkml.kernel.org/r/YUMfdA36fuyZ+/xt@hirez.programming.kicks-ass.net
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Hildenbrand <david@redhat.com>
Acked-by: Will Deacon <will@kernel.org>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Uladzislau Rezki <urezki@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit f255935b97 ("mm: cleanup the gfp_mask handling in
__vmalloc_area_node") added __GFP_NOWARN to gfp_mask unconditionally
however it disabled all output inside warn_alloc() call. This patch
saves original gfp_mask and provides it to all warn_alloc() calls.
Link: https://lkml.kernel.org/r/f4f3187b-9684-e426-565d-827c2a9bbb0e@virtuozzo.com
Fixes: f255935b97 ("mm: cleanup the gfp_mask handling in __vmalloc_area_node")
Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Cc: Uladzislau Rezki (Sony) <urezki@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
All this vm_unacct_memory(charged) dance seems to complicate the life
without a good reason. Furthermore, it seems not always done right on
error-pathes in mremap_to(). And worse than that: this `charged'
difference is sometimes double-accounted for growing MREMAP_DONTUNMAP
mremap()s in move_vma():
if (security_vm_enough_memory_mm(mm, new_len >> PAGE_SHIFT))
Let's not do this. Account memory in mremap() fast-path for growing
VMAs or in move_vma() for actually moving things. The same simpler way
as it's done by vm_stat_account(), but with a difference to call
security_vm_enough_memory_mm() before copying/adjusting VMA.
Originally noticed by Chen Wandun:
https://lkml.kernel.org/r/20210717101942.120607-1-chenwandun@huawei.com
Link: https://lkml.kernel.org/r/20210721131320.522061-1-dima@arista.com
Fixes: e346b38130 ("mm/mremap: add MREMAP_DONTUNMAP to mremap()")
Signed-off-by: Dmitry Safonov <dima@arista.com>
Acked-by: Brian Geffon <bgeffon@google.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chen Wandun <chenwandun@huawei.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Wei Yongjun <weiyongjun1@huawei.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
After adjustment, the repeated assignment of "prev" is avoided, and the
readability of the code is improved.
Link: https://lkml.kernel.org/r/20211012152444.4127-1-fishland@aliyun.com
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Liu Song <liu.song11@zte.com.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The smp_wmb() which is in the __pte_alloc() is used to ensure all ptes
setup is visible before the pte is made visible to other CPUs by being
put into page tables. We only need this when the pte is actually
populated, so move it to pmd_install(). __pte_alloc_kernel(),
__p4d_alloc(), __pud_alloc() and __pmd_alloc() are similar to this case.
We can also defer smp_wmb() to the place where the pmd entry is really
populated by preallocated pte. There are two kinds of user of
preallocated pte, one is filemap & finish_fault(), another is THP. The
former does not need another smp_wmb() because the smp_wmb() has been
done by pmd_install(). Fortunately, the latter also does not need
another smp_wmb() because there is already a smp_wmb() before populating
the new pte when the THP uses a preallocated pte to split a huge pmd.
Link: https://lkml.kernel.org/r/20210901102722.47686-3-zhengqi.arch@bytedance.com
Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Acked-by: David Hildenbrand <david@redhat.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Mika Penttila <mika.penttila@nextfour.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "Do some code cleanups related to mm", v3.
This patch (of 2):
Currently we have three times the same few lines repeated in the code.
Deduplicate them by newly introduced pmd_install() helper.
Link: https://lkml.kernel.org/r/20210901102722.47686-1-zhengqi.arch@bytedance.com
Link: https://lkml.kernel.org/r/20210901102722.47686-2-zhengqi.arch@bytedance.com
Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Mika Penttila <mika.penttila@nextfour.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Use the helper for the checks. Rename "check_mapping" into
"zap_mapping" because "check_mapping" looks like a bool but in fact it
stores the mapping itself. When it's set, we check the mapping (it must
be non-NULL). When it's cleared we skip the check, which works like the
old way.
Move the duplicated comments to the helper too.
Link: https://lkml.kernel.org/r/20210915181538.11288-1-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Alistair Popple <apopple@nvidia.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: "Kirill A . Shutemov" <kirill@shutemov.name>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The first_index/last_index parameters in zap_details are actually only
used in unmap_mapping_range_tree(). At the meantime, this function is
only called by unmap_mapping_pages() once.
Instead of passing these two variables through the whole stack of page
zapping code, remove them from zap_details and let them simply be
parameters of unmap_mapping_range_tree(), which is inlined.
Link: https://lkml.kernel.org/r/20210915181535.11238-1-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Alistair Popple <apopple@nvidia.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Liam Howlett <liam.howlett@oracle.com>
Acked-by: Hugh Dickins <hughd@google.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: "Kirill A . Shutemov" <kirill@shutemov.name>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
pte_unmap_same() will always unmap the pte pointer. After the unmap,
vmf->pte will not be valid any more, we should clear it.
It was safe only because no one is accessing vmf->pte after
pte_unmap_same() returns, since the only caller of pte_unmap_same() (so
far) is do_swap_page(), where vmf->pte will in most cases be overwritten
very soon.
Directly pass in vmf into pte_unmap_same() and then we can also avoid
the long parameter list too, which should be a nice cleanup.
Link: https://lkml.kernel.org/r/20210915181533.11188-1-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Liam Howlett <liam.howlett@oracle.com>
Acked-by: Hugh Dickins <hughd@google.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: "Kirill A . Shutemov" <kirill@shutemov.name>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "mm: A few cleanup patches around zap, shmem and uffd", v4.
IMHO all of them are very nice cleanups to existing code already,
they're all small and self-contained. They'll be needed by uffd-wp
coming series.
This patch (of 4):
It was conditionally done previously, as there's one shmem special case
that we use SetPageDirty() instead. However that's not necessary and it
should be easier and cleaner to do it unconditionally in
mfill_atomic_install_pte().
The most recent discussion about this is here, where Hugh explained the
history of SetPageDirty() and why it's possible that it's not required
at all:
https://lore.kernel.org/lkml/alpine.LSU.2.11.2104121657050.1097@eggly.anvils/
Currently mfill_atomic_install_pte() has three callers:
1. shmem_mfill_atomic_pte
2. mcopy_atomic_pte
3. mcontinue_atomic_pte
After the change: case (1) should have its SetPageDirty replaced by the
dirty bit on pte (so we unify them together, finally), case (2) should
have no functional change at all as it has page_in_cache==false, case
(3) may add a dirty bit to the pte. However since case (3) is
UFFDIO_CONTINUE for shmem, it's merely 100% sure the page is dirty after
all because UFFDIO_CONTINUE normally requires another process to modify
the page cache and kick the faulted thread, so should not make a real
difference either.
This should make it much easier to follow on which case will set dirty
for uffd, as we'll simply set it all now for all uffd related ioctls.
Meanwhile, no special handling of SetPageDirty() if there's no need.
Link: https://lkml.kernel.org/r/20210915181456.10739-1-peterx@redhat.com
Link: https://lkml.kernel.org/r/20210915181456.10739-2-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Axel Rasmussen <axelrasmussen@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Yang Shi <shy828301@gmail.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: "Kirill A . Shutemov" <kirill@shutemov.name>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Annotating a pointer from __user to kernel and then back again might
confuse sparse. In copy_huge_page_from_user() it can be avoided by
removing the intermediate variable since it is never used.
Link: https://lkml.kernel.org/r/20210914150820.19326-1-amit.kachhap@arm.com
Signed-off-by: Amit Daniel Kachhap <amit.kachhap@arm.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Vincenzo Frascino <Vincenzo.Frascino@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The variable mm->total_vm could be accessed concurrently during mmaping
and system accounting as noticed by KCSAN,
BUG: KCSAN: data-race in __acct_update_integrals / mmap_region
read-write to 0xffffa40267bd14c8 of 8 bytes by task 15609 on cpu 3:
mmap_region+0x6dc/0x1400
do_mmap+0x794/0xca0
vm_mmap_pgoff+0xdf/0x150
ksys_mmap_pgoff+0xe1/0x380
do_syscall_64+0x37/0x50
entry_SYSCALL_64_after_hwframe+0x44/0xa9
read to 0xffffa40267bd14c8 of 8 bytes by interrupt on cpu 2:
__acct_update_integrals+0x187/0x1d0
acct_account_cputime+0x3c/0x40
update_process_times+0x5c/0x150
tick_sched_timer+0x184/0x210
__run_hrtimer+0x119/0x3b0
hrtimer_interrupt+0x350/0xaa0
__sysvec_apic_timer_interrupt+0x7b/0x220
asm_call_irq_on_stack+0x12/0x20
sysvec_apic_timer_interrupt+0x4d/0x80
asm_sysvec_apic_timer_interrupt+0x12/0x20
smp_call_function_single+0x192/0x2b0
perf_install_in_context+0x29b/0x4a0
__se_sys_perf_event_open+0x1a98/0x2550
__x64_sys_perf_event_open+0x63/0x70
do_syscall_64+0x37/0x50
entry_SYSCALL_64_after_hwframe+0x44/0xa9
Reported by Kernel Concurrency Sanitizer on:
CPU: 2 PID: 15610 Comm: syz-executor.3 Not tainted 5.10.0+ #2
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
Ubuntu-1.8.2-1ubuntu1 04/01/2014
In vm_stat_account which called by mmap_region, increase total_vm, and
__acct_update_integrals may read total_vm at the same time. This will
cause a data race which lead to undefined behaviour. To avoid potential
bad read/write, volatile property and barrier are both used to avoid
undefined behaviour.
Link: https://lkml.kernel.org/r/20210913105550.1569419-1-liupeng256@huawei.com
Signed-off-by: Peng Liu <liupeng256@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Memory cgroup charging allows killed or exiting tasks to exceed the hard
limit. It is assumed that the amount of the memory charged by those
tasks is bound and most of the memory will get released while the task
is exiting. This is resembling a heuristic for the global OOM situation
when tasks get access to memory reserves. There is no global memory
shortage at the memcg level so the memcg heuristic is more relieved.
The above assumption is overly optimistic though. E.g. vmalloc can
scale to really large requests and the heuristic would allow that. We
used to have an early break in the vmalloc allocator for killed tasks
but this has been reverted by commit b8c8a338f7 ("Revert "vmalloc:
back off when the current task is killed""). There are likely other
similar code paths which do not check for fatal signals in an
allocation&charge loop. Also there are some kernel objects charged to a
memcg which are not bound to a process life time.
It has been observed that it is not really hard to trigger these
bypasses and cause global OOM situation.
One potential way to address these runaways would be to limit the amount
of excess (similar to the global OOM with limited oom reserves). This
is certainly possible but it is not really clear how much of an excess
is desirable and still protects from global OOMs as that would have to
consider the overall memcg configuration.
This patch is addressing the problem by removing the heuristic
altogether. Bypass is only allowed for requests which either cannot
fail or where the failure is not desirable while excess should be still
limited (e.g. atomic requests). Implementation wise a killed or dying
task fails to charge if it has passed the OOM killer stage. That should
give all forms of reclaim chance to restore the limit before the failure
(ENOMEM) and tell the caller to back off.
In addition, this patch renames should_force_charge() helper to
task_is_dying() because now its use is not associated witch forced
charging.
This patch depends on pagefault_out_of_memory() to not trigger
out_of_memory(), because then a memcg failure can unwind to VM_FAULT_OOM
and cause a global OOM killer.
Link: https://lkml.kernel.org/r/8f5cebbb-06da-4902-91f0-6566fc4b4203@virtuozzo.com
Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
Suggested-by: Michal Hocko <mhocko@suse.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Roman Gushchin <guro@fb.com>
Cc: Uladzislau Rezki <urezki@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Any allocation failure during the #PF path will return with VM_FAULT_OOM
which in turn results in pagefault_out_of_memory. This can happen for 2
different reasons. a) Memcg is out of memory and we rely on
mem_cgroup_oom_synchronize to perform the memcg OOM handling or b)
normal allocation fails.
The latter is quite problematic because allocation paths already trigger
out_of_memory and the page allocator tries really hard to not fail
allocations. Anyway, if the OOM killer has been already invoked there
is no reason to invoke it again from the #PF path. Especially when the
OOM condition might be gone by that time and we have no way to find out
other than allocate.
Moreover if the allocation failed and the OOM killer hasn't been invoked
then we are unlikely to do the right thing from the #PF context because
we have already lost the allocation context and restictions and
therefore might oom kill a task from a different NUMA domain.
This all suggests that there is no legitimate reason to trigger
out_of_memory from pagefault_out_of_memory so drop it. Just to be sure
that no #PF path returns with VM_FAULT_OOM without allocation print a
warning that this is happening before we restart the #PF.
[VvS: #PF allocation can hit into limit of cgroup v1 kmem controller.
This is a local problem related to memcg, however, it causes unnecessary
global OOM kills that are repeated over and over again and escalate into a
real disaster. This has been broken since kmem accounting has been
introduced for cgroup v1 (3.8). There was no kmem specific reclaim for
the separate limit so the only way to handle kmem hard limit was to return
with ENOMEM. In upstream the problem will be fixed by removing the
outdated kmem limit, however stable and LTS kernels cannot do it and are
still affected. This patch fixes the problem and should be backported
into stable/LTS.]
Link: https://lkml.kernel.org/r/f5fd8dd8-0ad4-c524-5f65-920b01972a42@virtuozzo.com
Signed-off-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Roman Gushchin <guro@fb.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Cc: Uladzislau Rezki <urezki@gmail.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "memcg: prohibit unconditional exceeding the limit of dying tasks", v3.
Memory cgroup charging allows killed or exiting tasks to exceed the hard
limit. It can be misused and allowed to trigger global OOM from inside
a memcg-limited container. On the other hand if memcg fails allocation,
called from inside #PF handler it triggers global OOM from inside
pagefault_out_of_memory().
To prevent these problems this patchset:
(a) removes execution of out_of_memory() from
pagefault_out_of_memory(), becasue nobody can explain why it is
necessary.
(b) allow memcg to fail allocation of dying/killed tasks.
This patch (of 3):
Any allocation failure during the #PF path will return with VM_FAULT_OOM
which in turn results in pagefault_out_of_memory which in turn executes
out_out_memory() and can kill a random task.
An allocation might fail when the current task is the oom victim and
there are no memory reserves left. The OOM killer is already handled at
the page allocator level for the global OOM and at the charging level
for the memcg one. Both have much more information about the scope of
allocation/charge request. This means that either the OOM killer has
been invoked properly and didn't lead to the allocation success or it
has been skipped because it couldn't have been invoked. In both cases
triggering it from here is pointless and even harmful.
It makes much more sense to let the killed task die rather than to wake
up an eternally hungry oom-killer and send him to choose a fatter victim
for breakfast.
Link: https://lkml.kernel.org/r/0828a149-786e-7c06-b70a-52d086818ea3@virtuozzo.com
Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
Suggested-by: Michal Hocko <mhocko@suse.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Roman Gushchin <guro@fb.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Cc: Uladzislau Rezki <urezki@gmail.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The non-memcg-aware lru is always skiped when traversing the global lru
list, which is not efficient. We can only add the memcg-aware lru to
the global lru list instead to make traversing more efficient.
Link: https://lkml.kernel.org/r/20211025124353.55781-1-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Roman Gushchin <guro@fb.com>
Cc: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Now the kmem states is only used to indicate whether the kmem is
offline. However, we can set ->kmemcg_id to -1 to indicate whether the
kmem is offline. Finally, we can remove the kmem states to simplify the
code.
Link: https://lkml.kernel.org/r/20211025125259.56624-1-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Acked-by: Roman Gushchin <guro@fb.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Since slab objects and kmem pages are charged to object cgroup instead
of memory cgroup, memcg_reparent_objcgs() will reparent this cgroup and
all its descendants to its parent cgroup. This already makes further
list_lru_add()'s add elements to the parent's list. So it is
unnecessary to change kmemcg_id of an offline cgroup to its parent's id.
It just wastes CPU cycles. Just remove the redundant code.
Link: https://lkml.kernel.org/r/20211025125102.56533-1-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Acked-by: Roman Gushchin <guro@fb.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Since commit 2788cf0c40 ("memcg: reparent list_lrus and free kmemcg_id
on css offline"), ->nr_items can be negative during memory cgroup
reparenting. In this case, list_lru_count_one() will return an unusual
and huge value, which can surprise users. At least for now it hasn't
affected any users. But it is better to let list_lru_count_ont()
returns zero when ->nr_items is negative.
Link: https://lkml.kernel.org/r/20211025124910.56433-1-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Roman Gushchin <guro@fb.com>
Cc: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Since commit e5bc3af773 ("rcu: Consolidate PREEMPT and !PREEMPT
synchronize_rcu()"), the critical section of spin lock can serve as an
RCU read-side critical section which already allows readers that hold
nlru->lock to avoid taking rcu lock. So just remove holding lock.
Link: https://lkml.kernel.org/r/20211025124534.56345-1-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Roman Gushchin <guro@fb.com>
Cc: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The deprecation process of kmem.limit_in_bytes started with the commit
0158115f70 ("memcg, kmem: deprecate kmem.limit_in_bytes") which also
explains in detail the motivation behind the deprecation. To summarize,
it is the unexpected behavior on hitting the kmem limit. This patch
moves the deprecation process to the next stage by disallowing to set
the kmem limit. In future we might just remove the kmem.limit_in_bytes
file completely.
[akpm@linux-foundation.org: s/ENOTSUPP/EOPNOTSUPP/]
[arnd@arndb.de: mark cancel_charge() inline]
Link: https://lkml.kernel.org/r/20211022070542.679839-1-arnd@kernel.org
Link: https://lkml.kernel.org/r/20211019153408.2916808-1-shakeelb@google.com
Signed-off-by: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Roman Gushchin <guro@fb.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Cc: Vasily Averin <vvs@virtuozzo.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
As noted in the "Deprecated Interfaces, Language Features, Attributes,
and Conventions" documentation [1], size calculations (especially
multiplication) should not be performed in memory allocator (or similar)
function arguments due to the risk of them overflowing.
This could lead to values wrapping around and a smaller allocation being
made than the caller was expecting. Using those allocations could lead
to linear overflows of heap memory and other misbehaviors.
So, use the struct_size() helper to do the arithmetic instead of the
argument "size + count * size" in the kvmalloc() functions.
Also, take the opportunity to refactor the memcpy() call to use the
flex_array_size() helper.
This code was detected with the help of Coccinelle and audited and fixed
manually.
[1] https://www.kernel.org/doc/html/latest/process/deprecated.html#open-coded-arithmetic-in-allocator-arguments
Link: https://lkml.kernel.org/r/20211017105929.9284-1-len.baker@gmx.com
Signed-off-by: Len Baker <len.baker@gmx.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: "Gustavo A. R. Silva" <gustavoars@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Since commit d648bcc7fe ("mm: kmem: make memcg_kmem_enabled()
irreversible"), the only thing memcg_free_kmem() does is to call
memcg_offline_kmem() when the memcg is still online which can happen
when online_css() fails due to -ENOMEM.
However, the name memcg_free_kmem() is confusing and it is more clear
and straight forward to call memcg_offline_kmem() directly from
mem_cgroup_css_free().
Link: https://lkml.kernel.org/r/20211005202450.11775-1-longman@redhat.com
Signed-off-by: Waiman Long <longman@redhat.com>
Suggested-by: Roman Gushchin <guro@fb.com>
Reviewed-by: Aaron Tomlin <atomlin@redhat.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Reviewed-by: Roman Gushchin <guro@fb.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The memcg stats can be flushed in multiple context and potentially in
parallel too. For example multiple parallel user space readers for
memcg stats will contend on the rstat locks with each other. There is
no need for that. We just need one flusher and everyone else can
benefit.
In addition after aa48e47e39 ("memcg: infrastructure to flush memcg
stats") the kernel periodically flush the memcg stats from the root, so,
the other flushers will potentially have much less work to do.
Link: https://lkml.kernel.org/r/20211001190040.48086-2-shakeelb@google.com
Signed-off-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: "Michal Koutný" <mkoutny@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
At the moment, the kernel flushes the memcg stats on every refault and
also on every reclaim iteration. Although rstat maintains per-cpu
update tree but on the flush the kernel still has to go through all the
cpu rstat update tree to check if there is anything to flush. This
patch adds the tracking on the stats update side to make flush side more
clever by skipping the flush if there is no update.
The stats update codepath is very sensitive performance wise for many
workloads and benchmarks. So, we can not follow what the commit
aa48e47e39 ("memcg: infrastructure to flush memcg stats") did which
was triggering async flush through queue_work() and caused a lot
performance regression reports. That got reverted by the commit
1f828223b7 ("memcg: flush lruvec stats in the refault").
In this patch we kept the stats update codepath very minimal and let the
stats reader side to flush the stats only when the updates are over a
specific threshold. For now the threshold is (nr_cpus * CHARGE_BATCH).
To evaluate the impact of this patch, an 8 GiB tmpfs file is created on
a system with swap-on-zram and the file was pushed to swap through
memory.force_empty interface. On reading the whole file, the memcg stat
flush in the refault code path is triggered. With this patch, we
observed 63% reduction in the read time of 8 GiB file.
Link: https://lkml.kernel.org/r/20211001190040.48086-1-shakeelb@google.com
Signed-off-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Reviewed-by: "Michal Koutný" <mkoutny@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
It is unused after the rework of commit f5df8635c5 ("mm: use
find_get_incore_page in memcontrol").
Link: https://lkml.kernel.org/r/20210916193014.80129-1-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Instead of calling put_page() one page at a time, pop pages off the list
if their refcount was too high and pass the remainder to
put_unref_page_list(). This should be a speed improvement, but I have
no measurements to support that. Current callers do not care about
performance, but I hope to add some which do.
Link: https://lkml.kernel.org/r/20211007192138.561673-1-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Anthony Yznaga <anthony.yznaga@oracle.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This one is just a minor nuisance for people going through /proc/swaps
if any of their swapareas is bigger than, or equal to 1073741824 pages
(4TB).
seq_printf() format string casts as uint the conversion from pages to
KB, and that will overflow in the aforementioned case.
Albeit being almost unthinkable that someone would actually set up such
big of a single swaparea, there is a ticket recently filed against RHEL:
https://bugzilla.redhat.com/show_bug.cgi?id=2008812
Given that all other codesites that use format strings for the same swap
pages-to-KB conversion do cast it as ulong, this patch just follows
suit.
Link: https://lkml.kernel.org/r/20211006184011.2579054-1-aquini@redhat.com
Signed-off-by: Rafael Aquini <aquini@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The request_queue pointer returned from bdev_get_queue() shall never be
NULL, so the null check is unnecessary, just remove it.
Link: https://lkml.kernel.org/r/20210917082111.33923-1-vulab@iscas.ac.cn
Signed-off-by: Xu Wang <vulab@iscas.ac.cn>
Acked-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit 6401c4eb57 ("mm: gup: fix potential pgmap refcnt leak in
__gup_device_huge()") simplified the return paths, but didn't go quite
far enough, as discussed in [1].
Remove the "ret" variable entirely, because there is enough information
already available to provide the return value.
[1] https://lore.kernel.org/r/CAHk-=wgQTRX=5SkCmS+zfmpqubGHGJvXX_HgnPG8JSpHKHBMeg@mail.gmail.com
Link: https://lkml.kernel.org/r/20210904004224.86391-1-jhubbard@nvidia.com
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Claudio Imbrenda <imbrenda@linux.ibm.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The fast path here is not needing any writeback, yet we spend time
setting up the xarray lookup data upfront. Move the part that actually
needs to iterate the address space mapping into a separate helper,
saving ~30% of the time here.
Link: https://lkml.kernel.org/r/49f67983-b802-8929-edab-d807f745c9ca@kernel.dk
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
It is not safe to check page->index without holding the page lock. It
can be changed if the page is moved between the swap cache and the page
cache for a shmem file, for example. There is a VM_BUG_ON below which
checks page->index is correct after taking the page lock.
Link: https://lkml.kernel.org/r/20210818144932.940640-1-willy@infradead.org
Fixes: 5c211ba29d ("mm: add and use find_lock_entries")
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reported-by: <syzbot+c87be4f669d920c76330@syzkaller.appspotmail.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We always go through i_size_read(), and we rarely end up needing it.
Push the read to down where we need to check it, which avoids it for
most cases.
It looks like we can even remove this check entirely, which might be
worth pursuing. But at least this takes it out of the hot path.
Link: https://lkml.kernel.org/r/6b67981f-57d4-c80e-bc07-6020aa601381@kernel.dk
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Acked-by: Chris Mason <clm@fb.com>
Cc: Josef Bacik <josef@redhat.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Pavel Begunkov <asml.silence@gmail.com>
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Move grabbing and releasing the bdi refcount out of the common
wb_init/wb_exit helpers into code that is only used for the non-default
memcg driven bdi_writeback structures.
[hch@lst.de: add comment]
Link: https://lkml.kernel.org/r/20211027074207.GA12793@lst.de
[akpm@linux-foundation.org: fix typo]
Link: https://lkml.kernel.org/r/20211021124441.668816-6-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Miquel Raynal <miquel.raynal@bootlin.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Vignesh Raghavendra <vigneshr@ti.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "simplify bdi unregistation".
This series simplifies the BDI code to get rid of the magic
auto-unregister feature that hid a recent block layer refcounting bug.
This patch (of 5):
To wind down the magic auto-unregister semantics we'll need to push this
into modular code.
Link: https://lkml.kernel.org/r/20211021124441.668816-1-hch@lst.de
Link: https://lkml.kernel.org/r/20211021124441.668816-2-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Miquel Raynal <miquel.raynal@bootlin.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Vignesh Raghavendra <vigneshr@ti.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
I have noticed that the previous macro is #ifndef CONFIG_SPARSEMEM. I
think the comment of #else should be CONFIG_SPARSEMEM.
Link: https://lkml.kernel.org/r/20211008140312.6492-1-zhangyinan2019@email.szu.edu.cn
Signed-off-by: Yinan Zhang <zhangyinan2019@email.szu.edu.cn>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The __Pxxx/__Sxxx macros are only for protection_map[] init. All usage
of them in linux should come from protection_map array.
Because a lot of architectures would re-initilize protection_map[]
array, eg: x86-mem_encrypt, m68k-motorola, mips, arm, sparc.
Using __P000 is not rigorous.
Link: https://lkml.kernel.org/r/20210924060821.1138281-1-guoren@kernel.org
Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Gavin Shan <gshan@redhat.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
As it's trying to cover the whole vma anyways, use direct vm_pgoff value
and vma_pages() rather than linear_page_index.
Link: https://lkml.kernel.org/r/20210917164756.8586-3-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Hugh Dickins <hughd@google.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
If an object is allocated on a tail page of a multi-page slab, kasan
will get the wrong tag because page->s_mem is NULL for tail pages. I'm
not quite sure what the user-visible effect of this might be.
Link: https://lkml.kernel.org/r/20211001024105.3217339-1-willy@infradead.org
Fixes: 7f94ffbc4c ("kasan: add hooks implementation for tag-based mode")
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: Marco Elver <elver@google.com>
Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Introduce a variant of kasan_record_aux_stack() that does not do any
memory allocation through stackdepot. This will permit using it in
contexts that cannot allocate any memory.
Link: https://lkml.kernel.org/r/20210913112609.2651084-6-elver@google.com
Signed-off-by: Marco Elver <elver@google.com>
Tested-by: Shuah Khan <skhan@linuxfoundation.org>
Acked-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: "Gustavo A. R. Silva" <gustavoars@kernel.org>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Taras Madan <tarasmadan@google.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vijayanand Jitta <vjitta@codeaurora.org>
Cc: Vinayak Menon <vinmenon@codeaurora.org>
Cc: Walter Wu <walter-zh.wu@mediatek.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Not required at all, and having this causes a huge kernel rebuild as
soon as something in dax.h changes.
Link: https://lkml.kernel.org/r/20210921082253.1859794-1-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
TRANSPARENT_HUGEPAGE:
There are potential non-deterministic delays to an RT thread if a
critical memory region is not THP-aligned and a non-RT buffer is
located in the same hugepage-aligned region. It's also possible for an
unrelated thread to migrate pages belonging to an RT task incurring
unexpected page faults due to memory defragmentation even if
khugepaged is disabled.
Regular HUGEPAGEs are not affected by this can be used.
NUMA_BALANCING:
There is a non-deterministic delay to mark PTEs PROT_NONE to gather
NUMA fault samples, increased page faults of regions even if mlocked
and non-deterministic delays when migrating pages.
[Mel Gorman worded 99% of the commit description].
Link: https://lore.kernel.org/all/20200304091159.GN3818@techsingularity.net/
Link: https://lore.kernel.org/all/20211026165100.ahz5bkx44lrrw5pt@linutronix.de/
Link: https://lkml.kernel.org/r/20211028143327.hfbxjze7palrpfgp@linutronix.de
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit 0ad9500e16 ("slub: prefetch next freelist pointer in
slab_alloc()") introduced prefetch_freepointer() because when other
cpu(s) freed objects into a page that current cpu owns, the freelist
link is hot on cpu(s) which freed objects and possibly very cold on
current cpu.
But if freelist link chain is hot on cpu(s) which freed objects, it's
better to invalidate that chain because they're not going to access
again within a short time.
So use prefetchw instead of prefetch. On supported architectures like
x86 and arm, it invalidates other copied instances of a cache line when
prefetching it.
Before:
Time: 91.677
Performance counter stats for 'hackbench -g 100 -l 10000':
1462938.07 msec cpu-clock # 15.908 CPUs utilized
18072550 context-switches # 12.354 K/sec
1018814 cpu-migrations # 696.416 /sec
104558 page-faults # 71.471 /sec
1580035699271 cycles # 1.080 GHz (54.51%)
2003670016013 instructions # 1.27 insn per cycle (54.31%)
5702204863 branch-misses (54.28%)
643368500985 cache-references # 439.778 M/sec (54.26%)
18475582235 cache-misses # 2.872 % of all cache refs (54.28%)
642206796636 L1-dcache-loads # 438.984 M/sec (46.87%)
18215813147 L1-dcache-load-misses # 2.84% of all L1-dcache accesses (46.83%)
653842996501 dTLB-loads # 446.938 M/sec (46.63%)
3227179675 dTLB-load-misses # 0.49% of all dTLB cache accesses (46.85%)
537531951350 iTLB-loads # 367.433 M/sec (54.33%)
114750630 iTLB-load-misses # 0.02% of all iTLB cache accesses (54.37%)
630135543177 L1-icache-loads # 430.733 M/sec (46.80%)
22923237620 L1-icache-load-misses # 3.64% of all L1-icache accesses (46.76%)
91.964452802 seconds time elapsed
43.416742000 seconds user
1422.441123000 seconds sys
After:
Time: 90.220
Performance counter stats for 'hackbench -g 100 -l 10000':
1437418.48 msec cpu-clock # 15.880 CPUs utilized
17694068 context-switches # 12.310 K/sec
958257 cpu-migrations # 666.651 /sec
100604 page-faults # 69.989 /sec
1583259429428 cycles # 1.101 GHz (54.57%)
2004002484935 instructions # 1.27 insn per cycle (54.37%)
5594202389 branch-misses (54.36%)
643113574524 cache-references # 447.409 M/sec (54.39%)
18233791870 cache-misses # 2.835 % of all cache refs (54.37%)
640205852062 L1-dcache-loads # 445.386 M/sec (46.75%)
17968160377 L1-dcache-load-misses # 2.81% of all L1-dcache accesses (46.79%)
651747432274 dTLB-loads # 453.415 M/sec (46.59%)
3127124271 dTLB-load-misses # 0.48% of all dTLB cache accesses (46.75%)
535395273064 iTLB-loads # 372.470 M/sec (54.38%)
113500056 iTLB-load-misses # 0.02% of all iTLB cache accesses (54.35%)
628871845924 L1-icache-loads # 437.501 M/sec (46.80%)
22585641203 L1-icache-load-misses # 3.59% of all L1-icache accesses (46.79%)
90.514819303 seconds time elapsed
43.877656000 seconds user
1397.176001000 seconds sys
Link: https://lkml.org/lkml/2021/10/8/598=20
Link: https://lkml.kernel.org/r/20211011144331.70084-1-42.hyeyoo@gmail.com
Signed-off-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The defaults are determined based on object size and can go up to 30 for
objects smaller than 256 bytes. Before the previous patch changed the
accounting, this could have made cpu partial list contain up to 30
pages. After that patch, only up to 2 pages with default allocation
order.
Very short lists limit the usefulness of the whole concept of cpu
partial lists, so this patch aims at a more reasonable default under the
new accounting. The defaults are quadrupled, except for object size >=
PAGE_SIZE where it's doubled. This makes the lists grow up to 10 pages
in practice.
A quick test of booting a kernel under virtme with 4GB RAM and 8 vcpus
shows the following slab memory usage after boot:
Before previous patch (using page->pobjects):
Slab: 36732 kB
SReclaimable: 14836 kB
SUnreclaim: 21896 kB
After previous patch (using page->pages):
Slab: 34720 kB
SReclaimable: 13716 kB
SUnreclaim: 21004 kB
After this patch (using page->pages, higher defaults):
Slab: 35252 kB
SReclaimable: 13944 kB
SUnreclaim: 21308 kB
In the same setup, I also ran 5 times:
hackbench -l 16000 -g 16
Differences in time were in the noise, we can compare slub stats as
given by slabinfo -r skbuff_head_cache (the other cache heavily used by
hackbench, kmalloc-cg-512 looks similar). Negligible stats left out for
brevity.
Before previous patch (using page->pobjects):
Objects: 1408, Memory Total: 401408 Used : 304128
Slab Perf Counter Alloc Free %Al %Fr
--------------------------------------------------
Fastpath 469952498 5946606 91 1
Slowpath 42053573 506059465 8 98
Page Alloc 41093 41044 0 0
Add partial 18 21229327 0 4
Remove partial 20039522 36051 3 0
Cpu partial list 4686640 24767229 0 4
RemoteObj/SlabFrozen 16 124027841 0 24
Total 512006071 512006071
Flushes 18
Slab Deactivation Occurrences %
-------------------------------------------------
Slab empty 4993 0%
Deactivation bypass 24767229 99%
Refilled from foreign frees 21972674 88%
After previous patch (using page->pages):
Objects: 480, Memory Total: 131072 Used : 103680
Slab Perf Counter Alloc Free %Al %Fr
--------------------------------------------------
Fastpath 473016294 5405653 92 1
Slowpath 38989777 506600418 7 98
Page Alloc 32717 32701 0 0
Add partial 3 22749164 0 4
Remove partial 11371127 32474 2 0
Cpu partial list 11686226 23090059 2 4
RemoteObj/SlabFrozen 2 67541803 0 13
Total 512006071 512006071
Flushes 3
Slab Deactivation Occurrences %
-------------------------------------------------
Slab empty 227 0%
Deactivation bypass 23090059 99%
Refilled from foreign frees 27585695 119%
After this patch (using page->pages, higher defaults):
Objects: 896, Memory Total: 229376 Used : 193536
Slab Perf Counter Alloc Free %Al %Fr
--------------------------------------------------
Fastpath 473799295 4980278 92 0
Slowpath 38206776 507025793 7 99
Page Alloc 32295 32267 0 0
Add partial 11 23291143 0 4
Remove partial 5815764 31278 1 0
Cpu partial list 18119280 23967320 3 4
RemoteObj/SlabFrozen 10 76974794 0 15
Total 512006071 512006071
Flushes 11
Slab Deactivation Occurrences %
-------------------------------------------------
Slab empty 989 0%
Deactivation bypass 23967320 99%
Refilled from foreign frees 32358473 135%
As expected, memory usage dropped significantly with change of
accounting, increasing the defaults increased it, but not as much. The
number of page allocation/frees dropped significantly with the new
accounting, but didn't increase with the higher defaults.
Interestingly, the number of fasthpath allocations increased, as well as
allocations from the cpu partial list, even though it's shorter.
Link: https://lkml.kernel.org/r/20211012134651.11258-2-vbabka@suse.cz
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Jann Horn <jannh@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Roman Gushchin <guro@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
With CONFIG_SLUB_CPU_PARTIAL enabled, SLUB keeps a percpu list of
partial slabs that can be promoted to cpu slab when the previous one is
depleted, without accessing the shared partial list. A slab can be
added to this list by 1) refill of an empty list from get_partial_node()
- once we really have to access the shared partial list, we acquire
multiple slabs to amortize the cost of locking, and 2) first free to a
previously full slab - instead of putting the slab on a shared partial
list, we can more cheaply freeze it and put it on the per-cpu list.
To control how large a percpu partial list can grow for a kmem cache,
set_cpu_partial() calculates a target number of free objects on each
cpu's percpu partial list, and this can be also set by the sysfs file
cpu_partial.
However, the tracking of actual number of objects is imprecise, in order
to limit overhead from cpu X freeing an objects to a slab on percpu
partial list of cpu Y. Basically, the percpu partial slabs form a
single linked list, and when we add a new slab to the list with current
head "oldpage", we set in the struct page of the slab we're adding:
page->pages = oldpage->pages + 1; // this is precise
page->pobjects = oldpage->pobjects + (page->objects - page->inuse);
page->next = oldpage;
Thus the real number of free objects in the slab (objects - inuse) is
only determined at the moment of adding the slab to the percpu partial
list, and further freeing doesn't update the pobjects counter nor
propagate it to the current list head. As Jann reports [1], this can
easily lead to large inaccuracies, where the target number of objects
(up to 30 by default) can translate to the same number of (empty) slab
pages on the list. In case 2) above, we put a slab with 1 free object
on the list, thus only increase page->pobjects by 1, even if there are
subsequent frees on the same slab. Jann has noticed this in practice
and so did we [2] when investigating significant increase of kmemcg
usage after switching from SLAB to SLUB.
While this is no longer a problem in kmemcg context thanks to the
accounting rewrite in 5.9, the memory waste is still not ideal and it's
questionable whether it makes sense to perform free object count based
control when object counts can easily become so much inaccurate. So
this patch converts the accounting to be based on number of pages only
(which is precise) and removes the page->pobjects field completely.
This is also ultimately simpler.
To retain the existing set_cpu_partial() heuristic, first calculate the
target number of objects as previously, but then convert it to target
number of pages by assuming the pages will be half-filled on average.
This assumption might obviously also be inaccurate in practice, but
cannot degrade to actual number of pages being equal to the target
number of objects.
We could also skip the intermediate step with target number of objects
and rewrite the heuristic in terms of pages. However we still have the
sysfs file cpu_partial which uses number of objects and could break
existing users if it suddenly becomes number of pages, so this patch
doesn't do that.
In practice, after this patch the heuristics limit the size of percpu
partial list up to 2 pages. In case of a reported regression (which
would mean some workload has benefited from the previous imprecise
object based counting), we can tune the heuristics to get a better
compromise within the new scheme, while still avoid the unexpectedly
long percpu partial lists.
[1] https://lore.kernel.org/linux-mm/CAG48ez2Qx5K1Cab-m8BdSibp6wLTip6ro4=-umR7BLsEgjEYzA@mail.gmail.com/
[2] https://lore.kernel.org/all/2f0f46e8-2535-410a-1859-e9cfa4e57c18@suse.cz/
==========
Evaluation
==========
Mel was kind enough to run v1 through mmtests machinery for netperf
(localhost) and hackbench and, for most significant results see below.
So there are some apparent regressions, especially with hackbench, which
I think ultimately boils down to having shorter percpu partial lists on
average and some benchmarks benefiting from longer ones. Monitoring
slab usage also indicated less memory usage by slab. Based on that, the
following patch will bump the defaults to allow longer percpu partial
lists than after this patch.
However the goal is certainly not such that we would limit the percpu
partial lists to 30 pages just because previously a specific alloc/free
pattern could lead to the limit of 30 objects translate to a limit to 30
pages - that would make little sense. This is a correctness patch, and
if a workload benefits from larger lists, the sysfs tuning knobs are
still there to allow that.
Netperf
2-socket Intel(R) Xeon(R) Gold 5218R CPU @ 2.10GHz (20 cores, 40 threads per socket), 384GB RAM
TCP-RR:
hmean before 127045.79 after 121092.94 (-4.69%, worse)
stddev before 2634.37 after 1254.08
UDP-RR:
hmean before 166985.45 after 160668.94 ( -3.78%, worse)
stddev before 4059.69 after 1943.63
2-socket Intel(R) Xeon(R) CPU E5-2698 v4 @ 2.20GHz (20 cores, 40 threads per socket), 512GB RAM
TCP-RR:
hmean before 84173.25 after 76914.72 ( -8.62%, worse)
UDP-RR:
hmean before 93571.12 after 96428.69 ( 3.05%, better)
stddev before 23118.54 after 16828.14
2-socket Intel(R) Xeon(R) CPU E5-2670 v3 @ 2.30GHz (12 cores, 24 threads per socket), 64GB RAM
TCP-RR:
hmean before 49984.92 after 48922.27 ( -2.13%, worse)
stddev before 6248.15 after 4740.51
UDP-RR:
hmean before 61854.31 after 68761.81 ( 11.17%, better)
stddev before 4093.54 after 5898.91
other machines - within 2%
Hackbench
(results before and after the patch, negative % means worse)
2-socket AMD EPYC 7713 (64 cores, 128 threads per core), 256GB RAM
hackbench-process-sockets
Amean 1 0.5380 0.5583 ( -3.78%)
Amean 4 0.7510 0.8150 ( -8.52%)
Amean 7 0.7930 0.9533 ( -20.22%)
Amean 12 0.7853 1.1313 ( -44.06%)
Amean 21 1.1520 1.4993 ( -30.15%)
Amean 30 1.6223 1.9237 ( -18.57%)
Amean 48 2.6767 2.9903 ( -11.72%)
Amean 79 4.0257 5.1150 ( -27.06%)
Amean 110 5.5193 7.4720 ( -35.38%)
Amean 141 7.2207 9.9840 ( -38.27%)
Amean 172 8.4770 12.1963 ( -43.88%)
Amean 203 9.6473 14.3137 ( -48.37%)
Amean 234 11.3960 18.7917 ( -64.90%)
Amean 265 13.9627 22.4607 ( -60.86%)
Amean 296 14.9163 26.0483 ( -74.63%)
hackbench-thread-sockets
Amean 1 0.5597 0.5877 ( -5.00%)
Amean 4 0.7913 0.8960 ( -13.23%)
Amean 7 0.8190 1.0017 ( -22.30%)
Amean 12 0.9560 1.1727 ( -22.66%)
Amean 21 1.7587 1.5660 ( 10.96%)
Amean 30 2.4477 1.9807 ( 19.08%)
Amean 48 3.4573 3.0630 ( 11.41%)
Amean 79 4.7903 5.1733 ( -8.00%)
Amean 110 6.1370 7.4220 ( -20.94%)
Amean 141 7.5777 9.2617 ( -22.22%)
Amean 172 9.2280 11.0907 ( -20.18%)
Amean 203 10.2793 13.3470 ( -29.84%)
Amean 234 11.2410 17.1070 ( -52.18%)
Amean 265 12.5970 23.3323 ( -85.22%)
Amean 296 17.1540 24.2857 ( -41.57%)
2-socket Intel(R) Xeon(R) Gold 5218R CPU @ 2.10GHz (20 cores, 40 threads
per socket), 384GB RAM
hackbench-process-sockets
Amean 1 0.5760 0.4793 ( 16.78%)
Amean 4 0.9430 0.9707 ( -2.93%)
Amean 7 1.5517 1.8843 ( -21.44%)
Amean 12 2.4903 2.7267 ( -9.49%)
Amean 21 3.9560 4.2877 ( -8.38%)
Amean 30 5.4613 5.8343 ( -6.83%)
Amean 48 8.5337 9.2937 ( -8.91%)
Amean 79 14.0670 15.2630 ( -8.50%)
Amean 110 19.2253 21.2467 ( -10.51%)
Amean 141 23.7557 25.8550 ( -8.84%)
Amean 172 28.4407 29.7603 ( -4.64%)
Amean 203 33.3407 33.9927 ( -1.96%)
Amean 234 38.3633 39.1150 ( -1.96%)
Amean 265 43.4420 43.8470 ( -0.93%)
Amean 296 48.3680 48.9300 ( -1.16%)
hackbench-thread-sockets
Amean 1 0.6080 0.6493 ( -6.80%)
Amean 4 1.0000 1.0513 ( -5.13%)
Amean 7 1.6607 2.0260 ( -22.00%)
Amean 12 2.7637 2.9273 ( -5.92%)
Amean 21 5.0613 4.5153 ( 10.79%)
Amean 30 6.3340 6.1140 ( 3.47%)
Amean 48 9.0567 9.5577 ( -5.53%)
Amean 79 14.5657 15.7983 ( -8.46%)
Amean 110 19.6213 21.6333 ( -10.25%)
Amean 141 24.1563 26.2697 ( -8.75%)
Amean 172 28.9687 30.2187 ( -4.32%)
Amean 203 33.9763 34.6970 ( -2.12%)
Amean 234 38.8647 39.3207 ( -1.17%)
Amean 265 44.0813 44.1507 ( -0.16%)
Amean 296 49.2040 49.4330 ( -0.47%)
2-socket Intel(R) Xeon(R) CPU E5-2698 v4 @ 2.20GHz (20 cores, 40 threads
per socket), 512GB RAM
hackbench-process-sockets
Amean 1 0.5027 0.5017 ( 0.20%)
Amean 4 1.1053 1.2033 ( -8.87%)
Amean 7 1.8760 2.1820 ( -16.31%)
Amean 12 2.9053 3.1810 ( -9.49%)
Amean 21 4.6777 4.9920 ( -6.72%)
Amean 30 6.5180 6.7827 ( -4.06%)
Amean 48 10.0710 10.5227 ( -4.48%)
Amean 79 16.4250 17.5053 ( -6.58%)
Amean 110 22.6203 24.4617 ( -8.14%)
Amean 141 28.0967 31.0363 ( -10.46%)
Amean 172 34.4030 36.9233 ( -7.33%)
Amean 203 40.5933 43.0850 ( -6.14%)
Amean 234 46.6477 48.7220 ( -4.45%)
Amean 265 53.0530 53.9597 ( -1.71%)
Amean 296 59.2760 59.9213 ( -1.09%)
hackbench-thread-sockets
Amean 1 0.5363 0.5330 ( 0.62%)
Amean 4 1.1647 1.2157 ( -4.38%)
Amean 7 1.9237 2.2833 ( -18.70%)
Amean 12 2.9943 3.3110 ( -10.58%)
Amean 21 4.9987 5.1880 ( -3.79%)
Amean 30 6.7583 7.0043 ( -3.64%)
Amean 48 10.4547 10.8353 ( -3.64%)
Amean 79 16.6707 17.6790 ( -6.05%)
Amean 110 22.8207 24.4403 ( -7.10%)
Amean 141 28.7090 31.0533 ( -8.17%)
Amean 172 34.9387 36.8260 ( -5.40%)
Amean 203 41.1567 43.0450 ( -4.59%)
Amean 234 47.3790 48.5307 ( -2.43%)
Amean 265 53.9543 54.6987 ( -1.38%)
Amean 296 60.0820 60.2163 ( -0.22%)
1-socket Intel(R) Xeon(R) CPU E3-1240 v5 @ 3.50GHz (4 cores, 8 threads),
32 GB RAM
hackbench-process-sockets
Amean 1 1.4760 1.5773 ( -6.87%)
Amean 3 3.9370 4.0910 ( -3.91%)
Amean 5 6.6797 6.9357 ( -3.83%)
Amean 7 9.3367 9.7150 ( -4.05%)
Amean 12 15.7627 16.1400 ( -2.39%)
Amean 18 23.5360 23.6890 ( -0.65%)
Amean 24 31.0663 31.3137 ( -0.80%)
Amean 30 38.7283 39.0037 ( -0.71%)
Amean 32 41.3417 41.6097 ( -0.65%)
hackbench-thread-sockets
Amean 1 1.5250 1.6043 ( -5.20%)
Amean 3 4.0897 4.2603 ( -4.17%)
Amean 5 6.7760 7.0933 ( -4.68%)
Amean 7 9.4817 9.9157 ( -4.58%)
Amean 12 15.9610 16.3937 ( -2.71%)
Amean 18 23.9543 24.3417 ( -1.62%)
Amean 24 31.4400 31.7217 ( -0.90%)
Amean 30 39.2457 39.5467 ( -0.77%)
Amean 32 41.8267 42.1230 ( -0.71%)
2-socket Intel(R) Xeon(R) CPU E5-2670 v3 @ 2.30GHz (12 cores, 24 threads
per socket), 64GB RAM
hackbench-process-sockets
Amean 1 1.0347 1.0880 ( -5.15%)
Amean 4 1.7267 1.8527 ( -7.30%)
Amean 7 2.6707 2.8110 ( -5.25%)
Amean 12 4.1617 4.3383 ( -4.25%)
Amean 21 7.0070 7.2600 ( -3.61%)
Amean 30 9.9187 10.2397 ( -3.24%)
Amean 48 15.6710 16.3923 ( -4.60%)
Amean 79 24.7743 26.1247 ( -5.45%)
Amean 110 34.3000 35.9307 ( -4.75%)
Amean 141 44.2043 44.8010 ( -1.35%)
Amean 172 54.2430 54.7260 ( -0.89%)
Amean 192 60.6557 60.9777 ( -0.53%)
hackbench-thread-sockets
Amean 1 1.0610 1.1353 ( -7.01%)
Amean 4 1.7543 1.9140 ( -9.10%)
Amean 7 2.7840 2.9573 ( -6.23%)
Amean 12 4.3813 4.4937 ( -2.56%)
Amean 21 7.3460 7.5350 ( -2.57%)
Amean 30 10.2313 10.5190 ( -2.81%)
Amean 48 15.9700 16.5940 ( -3.91%)
Amean 79 25.3973 26.6637 ( -4.99%)
Amean 110 35.1087 36.4797 ( -3.91%)
Amean 141 45.8220 46.3053 ( -1.05%)
Amean 172 55.4917 55.7320 ( -0.43%)
Amean 192 62.7490 62.5410 ( 0.33%)
Link: https://lkml.kernel.org/r/20211012134651.11258-1-vbabka@suse.cz
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Reported-by: Jann Horn <jannh@google.com>
Cc: Roman Gushchin <guro@fb.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
After commit f227f0faf6 ("slub: fix unreclaimable slab stat for bulk
free"), the check for free nonslab page is replaced by VM_BUG_ON_PAGE,
which only check with CONFIG_DEBUG_VM enabled, but this config may
impact performance, so it only for debug.
Commit 0937502af7 ("slub: Add check for kfree() of non slab objects.")
add the ability, which should be needed in any configs to catch the
invalid free, they even could be potential issue, eg, memory corruption,
use after free and double free, so replace VM_BUG_ON_PAGE to
WARN_ON_ONCE, add object address printing to help use to debug the
issue.
Link: https://lkml.kernel.org/r/20210930070214.61499-1-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rienjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
