This are no users since commit 40d707f33d ("mm/ksm: use folio in
write_protect_page"), so remove DEFINE_PAGE_VMA_WALK().
Link: https://lkml.kernel.org/r/20240524053618.208895-1-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Alex Shi <alexs@kernel.org>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The page_memcg() only called by mod_memcg_page_state(), so squash it to
cleanup page_memcg().
Link: https://lkml.kernel.org/r/20240524014950.187805-1-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Change the llist_for_each_entry_safe function to the llist_for_each_entry
function and delete the next variable. Because the linked list is not
modified,the llist_for_each_entry_safe function is not required. No
functional changes are intended.
Link: https://lkml.kernel.org/r/20240513075830.2611-1-liyifei28@huawei.com
Signed-off-by: Yifei Li <liyifei28@huawei.com>
Acked-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Jiaqi Yan <jiaqiyan@google.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shiyang Ruan <ruansy.fnst@fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Commit 1b151e2435 ("block: Remove special-casing of compound pages")
caused a change in behaviour when releasing the pages if the buffer does
not start at the beginning of the page. This was because the calculation
of the number of pages to release was incorrect. This was fixed by commit
38b43539d6 ("block: Fix page refcounts for unaligned buffers in
__bio_release_pages()").
We pin the user buffer during direct I/O writes. If this buffer is a
hugepage, bio_release_page() will unpin it and decrement all references
and pin counts at ->bi_end_io. However, if any references to the hugepage
remain post-I/O, the hugepage will not be freed upon unmap, leading to a
memory leak.
This patch verifies that a hugepage, used as a user buffer for DIO
operations, is correctly freed upon unmapping, regardless of whether the
offsets are aligned or unaligned w.r.t page boundary.
Test Result Fail Scenario (Without the fix)
--------------------------------------------------------
[]# ./hugetlb_dio
TAP version 13
1..4
No. Free pages before allocation : 7
No. Free pages after munmap : 7
ok 1 : Huge pages freed successfully !
No. Free pages before allocation : 7
No. Free pages after munmap : 7
ok 2 : Huge pages freed successfully !
No. Free pages before allocation : 7
No. Free pages after munmap : 7
ok 3 : Huge pages freed successfully !
No. Free pages before allocation : 7
No. Free pages after munmap : 6
not ok 4 : Huge pages not freed!
Totals: pass:3 fail:1 xfail:0 xpass:0 skip:0 error:0
Test Result PASS Scenario (With the fix)
---------------------------------------------------------
[]#./hugetlb_dio
TAP version 13
1..4
No. Free pages before allocation : 7
No. Free pages after munmap : 7
ok 1 : Huge pages freed successfully !
No. Free pages before allocation : 7
No. Free pages after munmap : 7
ok 2 : Huge pages freed successfully !
No. Free pages before allocation : 7
No. Free pages after munmap : 7
ok 3 : Huge pages freed successfully !
No. Free pages before allocation : 7
No. Free pages after munmap : 7
ok 4 : Huge pages freed successfully !
Totals: pass:4 fail:0 xfail:0 xpass:0 skip:0 error:0
[donettom@linux.ibm.com: address review comments from Muhammad]
Link: https://lkml.kernel.org/r/20240604132801.23377-1-donettom@linux.ibm.com
[donettom@linux.ibm.com: add this test to run_vmtests.sh]
Link: https://lkml.kernel.org/r/20240607182000.6494-1-donettom@linux.ibm.com
Link: https://lkml.kernel.org/r/20240523063905.3173-1-donettom@linux.ibm.com
Fixes: 38b43539d6 ("block: Fix page refcounts for unaligned buffers in __bio_release_pages()")
Signed-off-by: Donet Tom <donettom@linux.ibm.com>
Signed-off-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
Co-developed-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
Reviewed-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Tony Battersby <tonyb@cybernetics.com>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "mm: add missing MODULE_DESCRIPTION() macros".
This fixes the instances of "WARNING: modpost: missing
MODULE_DESCRIPTION()" that I'm seeing in mm/.
This patch (of 4):
Fix the 'make W=1' warning:
WARNING: modpost: missing MODULE_DESCRIPTION() in mm/hwpoison-inject.o
Link: https://lkml.kernel.org/r/20240513-mm-md-v1-0-8c20e7d26842@quicinc.com
Link: https://lkml.kernel.org/r/20240513-mm-md-v1-1-8c20e7d26842@quicinc.com
Signed-off-by: Jeff Johnson <quic_jjohnson@quicinc.com>
Acked-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Marco Elver <elver@google.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Execs of dynamically linked binaries at 20-ish cores are bottlenecked on
the i_mmap_rwsem semaphore, while the biggest singular contributor is
free_pgd_range inducing the lock acquire back-to-back for all consecutive
mappings of a given file.
Tracing the count of said acquires while building the kernel shows:
[1, 2) 799579 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@|
[2, 3) 0 | |
[3, 4) 3009 | |
[4, 5) 3009 | |
[5, 6) 326442 |@@@@@@@@@@@@@@@@@@@@@ |
So in particular there were 326442 opportunities to coalesce 5 acquires
into 1.
Doing so increases execs per second by 4% (~50k to ~52k) when running
the benchmark linked below.
The lock remains the main bottleneck, I have not looked at other spots
yet.
Bench can be found here:
http://apollo.backplane.com/DFlyMisc/doexec.c
$ cc -O2 -o shared-doexec doexec.c
$ ./shared-doexec $(nproc)
Note this particular test makes sure binaries are separate, but the
loader is shared.
Stats collected on the patched kernel (+ "noinline") with:
bpftrace -e 'kprobe:unlink_file_vma_batch_process
{ @ = lhist(((struct unlink_vma_file_batch *)arg0)->count, 0, 8, 1); }'
Link: https://lkml.kernel.org/r/20240521234321.359501-1-mjguzik@gmail.com
Signed-off-by: Mateusz Guzik <mjguzik@gmail.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
While handling hwpoison in a THP page, it is possible that
try_to_split_thp_page() fails. For example, when the THP page has been
RDMA pinned. At this point, the kernel cannot isolate the poisoned THP
page, all it could do is to send a SIGBUS to the user process with
meaningful payload to give user-level recovery a chance.
Link: https://lkml.kernel.org/r/20240524215306.2705454-6-jane.chu@oracle.com
Signed-off-by: Jane Chu <jane.chu@oracle.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Acked-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Cc: Oscar Salvador <oalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Move hwpoison_filter() higher up as there is no need to spend a lot cycles
only to find out later that the page is supposed to be skipped from
hwpoison handling.
Link: https://lkml.kernel.org/r/20240524215306.2705454-5-jane.chu@oracle.com
Signed-off-by: Jane Chu <jane.chu@oracle.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Acked-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Cc: Oscar Salvador <oalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Added two explicit MF_MSG messages describing failure in
get_hwpoison_page. Attemped to document the definition of various action
names, and made a few adjustment to the action_result() calls.
Link: https://lkml.kernel.org/r/20240524215306.2705454-4-jane.chu@oracle.com
Signed-off-by: Jane Chu <jane.chu@oracle.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Acked-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Cc: Oscar Salvador <oalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The soft hwpoison injector via madvise(MADV_HWPOISON) operates in a
synchrous way in a sense, the injector is also a process under test, and
should it have the poisoned page mapped in its address space, it should
get killed as much as in a real UE situation. Doing so align with what
the madvise(2) man page says: " "This operation may result in the calling
process receiving a SIGBUS and the page being unmapped."
Link: https://lkml.kernel.org/r/20240524215306.2705454-3-jane.chu@oracle.com
Signed-off-by: Jane Chu <jane.chu@oracle.com>
Reviewed-by: Oscar Salvador <oalvador@suse.de>
Acked-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Cc: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "Enhance soft hwpoison handling and injection", v4.
This series is aimed at the following enhancements:
- Let one hwpoison injector, that is, madvise(MADV_HWPOISON) to behave
more like as if a real UE occurred. Because the other two injectors
such as hwpoison-inject and the 'einj' on x86 can't, and it seems to me
we need a better simulation to real UE scenario.
- For years, if the kernel is unable to unmap a hwpoisoned page, it send
a SIGKILL instead of SIGBUS to prevent user process from potentially
accessing the page again. But in doing so, the user process also lose
important information: vaddr, for recovery. Fortunately, the kernel
already has code to kill process re-accessing a hwpoisoned page, so
remove the '!unmap_success' check.
- Right now, if a thp page under GUP longterm pin is hwpoisoned, and
kernel cannot split the thp page, memory-failure simply ignores the UE
and returns. That's not ideal, it could deliver a SIGBUS with useful
information for userspace recovery.
This patch (of 5):
For years when it comes down to kill a process due to hwpoison, a SIGBUS
is delivered only if unmap has been successful. Otherwise, a SIGKILL is
delivered. And the reason for that is to prevent the involved process
from accessing the hwpoisoned page again.
Since then a lot has changed, a hwpoisoned page is marked and upon being
re-accessed, the memory-failure handler invokes kill_accessing_process()
to kill the process immediately. So let's take out the '!unmap_success'
factor and try to deliver SIGBUS if possible.
Link: https://lkml.kernel.org/r/20240524215306.2705454-1-jane.chu@oracle.com
Link: https://lkml.kernel.org/r/20240524215306.2705454-2-jane.chu@oracle.com
Signed-off-by: Jane Chu <jane.chu@oracle.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Acked-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Cc: Oscar Salvador <oalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Let us simplify the code by update_mmu_tlb_range().
Link: https://lkml.kernel.org/r/20240522061204.117421-4-libang.li@antgroup.com
Signed-off-by: Bang Li <libang.li@antgroup.com>
Reviewed-by: Lance Yang <ioworker0@gmail.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Let's make update_mmu_tlb() simply a generic wrapper around
update_mmu_tlb_range(). Only the latter can now be overridden by the
architecture. We can now remove __HAVE_ARCH_UPDATE_MMU_TLB as well.
Link: https://lkml.kernel.org/r/20240522061204.117421-3-libang.li@antgroup.com
Signed-off-by: Bang Li <libang.li@antgroup.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Lance Yang <ioworker0@gmail.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "Add update_mmu_tlb_range() to simplify code", v4.
This series of commits mainly adds the update_mmu_tlb_range() to batch
update tlb in an address range and implement update_mmu_tlb() using
update_mmu_tlb_range().
After commit 19eaf44954 ("mm: thp: support allocation of anonymous
multi-size THP"), We may need to batch update tlb of a certain address
range by calling update_mmu_tlb() in a loop. Using the
update_mmu_tlb_range(), we can simplify the code and possibly reduce the
execution of some unnecessary code in some architectures.
This patch (of 3):
Add update_mmu_tlb_range(), we can batch update tlb of an address range.
Link: https://lkml.kernel.org/r/20240522061204.117421-1-libang.li@antgroup.com
Link: https://lkml.kernel.org/r/20240522061204.117421-2-libang.li@antgroup.com
Signed-off-by: Bang Li <libang.li@antgroup.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Lance Yang <ioworker0@gmail.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Post FEAT_LPA2, the Aarch64 Linux kernel extends higher address support to
4K and 16K translation granules. To support testing this out, we need to
do away with static initialization of page size, while still maintaining
the nice array of testcases; this can be achieved by initializing and
populating the array as a stack variable, and filling in the page size and
hugepage size at runtime.
Link: https://lkml.kernel.org/r/20240522070435.773918-3-dev.jain@arm.com
Signed-off-by: Dev Jain <dev.jain@arm.com>
Suggested-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "Restructure va_high_addr_switch".
The va_high_addr_switch memory selftest tests out some corner cases
related to allocation and page/hugepage faulting around the switch
boundary. Currently, the page size and hugepage size have been statically
defined. Post FEAT_LPA2, the Aarch64 Linux kernel adds support for 4k and
16k translation granules on higher addresses; we restructure the test to
support the same. In addition, we avoid invocation of the binary twice,
in the shell script, to reduce test noise.
This patch (of 2):
When invoking the binary with "--run-hugetlb" flag, the testcases
involving the base page are anyways going to be run. Therefore, remove
duplication by invoking the binary only once.
Link: https://lkml.kernel.org/r/20240522070435.773918-1-dev.jain@arm.com
Link: https://lkml.kernel.org/r/20240522070435.773918-2-dev.jain@arm.com
Signed-off-by: Dev Jain <dev.jain@arm.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Using insert_page() we might have previously ended up passing the zeropage
into rmap code. Make sure that won't happen again.
Note that we won't check the huge zeropage for now, which might still end
up in RMAP code.
Link: https://lkml.kernel.org/r/20240522125713.775114-4-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Vincent Donnefort <vdonnefort@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
For now we only get the (small) zeropage mapped to user space in four
cases (excluding VM_PFNMAP mappings, such as /proc/vmstat):
(1) Read page faults in anonymous VMAs (MAP_PRIVATE|MAP_ANON):
do_anonymous_page() will not refcount it and map it pte_mkspecial()
(2) UFFDIO_ZEROPAGE on anonymous VMA or COW mapping of shmem
(MAP_PRIVATE). mfill_atomic_pte_zeropage() will not refcount it and
map it pte_mkspecial().
(3) KSM in mergeable VMA (anonymous VMA or COW mapping).
cmp_and_merge_page() will not refcount it and map it
pte_mkspecial().
(4) FSDAX as an optimization for holes.
vmf_insert_mixed()->__vm_insert_mixed() might end up calling
insert_page() without CONFIG_ARCH_HAS_PTE_SPECIAL, refcounting the
zeropage and not mapping it pte_mkspecial(). With
CONFIG_ARCH_HAS_PTE_SPECIAL, we'll call insert_pfn() where we will
not refcount it and map it pte_mkspecial().
In case (4), we might not have VM_MIXEDMAP set: while fs/fuse/dax.c sets
VM_MIXEDMAP, we removed it for ext4 fsdax in commit e1fb4a0864 ("dax:
remove VM_MIXEDMAP for fsdax and device dax") and for XFS in commit
e1fb4a0864 ("dax: remove VM_MIXEDMAP for fsdax and device dax").
Without CONFIG_ARCH_HAS_PTE_SPECIAL and with VM_MIXEDMAP, vm_normal_page()
would currently return the zeropage. We'll refcount the zeropage when
mapping and when unmapping.
Without CONFIG_ARCH_HAS_PTE_SPECIAL and without VM_MIXEDMAP,
vm_normal_page() would currently refuse to return the zeropage. So we'd
refcount it when mapping but not when unmapping it ... do we have fsdax
without CONFIG_ARCH_HAS_PTE_SPECIAL in practice? Hard to tell.
Independent of that, we should never refcount the zeropage when we might
be holding that reference for a long time, because even without an
accounting imbalance we might overflow the refcount. As there is interest
in using the zeropage also in other VM_MIXEDMAP mappings, let's add clean
support for that in the cases where it makes sense:
(A) Never refcount the zeropage when mapping it:
In insert_page(), special-case the zeropage, do not refcount it, and use
pte_mkspecial(). Don't involve insert_pfn(), adjusting insert_page()
looks cleaner than branching off to insert_pfn().
(B) Never refcount the zeropage when unmapping it:
In vm_normal_page(), also don't return the zeropage in a VM_MIXEDMAP
mapping without CONFIG_ARCH_HAS_PTE_SPECIAL. Add a VM_WARN_ON_ONCE()
sanity check if we'd ever return the zeropage, which could happen if
someone forgets to set pte_mkspecial() when mapping the zeropage.
Document that.
(C) Allow the zeropage only where reasonable
s390x never wants the zeropage in some processes running legacy KVM guests
that make use of storage keys. So disallow that.
Further, using the zeropage in COW mappings is unproblematic (just what we
do for other COW mappings), because FAULT_FLAG_UNSHARE can just unshare it
and GUP with FOLL_LONGTERM would work as expected.
Similarly, mappings that can never have writable PTEs (implying no write
faults) are also not problematic, because nothing could end up mapping the
PTE writable by mistake later. But in case we could have writable PTEs,
we'll only allow the zeropage in FSDAX VMAs, that are incompatible with
GUP and are blocked there completely.
We'll always require the zeropage to be mapped with pte_special().
GUP-fast will reject the zeropage that way, but GUP-slow will allow it.
(Note that GUP does not refcount the zeropage with FOLL_PIN, because there
were issues with overflowing the refcount in the past).
Add sanity checks to can_change_pte_writable() and wp_page_reuse(), to
catch early during testing if we'd ever find a zeropage unexpectedly in
code that wants to upgrade write permissions.
Convert the BUG_ON in vm_mixed_ok() to an ordinary check and simply fail
with VM_FAULT_SIGBUS, like we do for other sanity checks. Drop the stale
comment regarding reserved pages from insert_page().
Note that:
* we won't mess with VM_PFNMAP mappings for now. remap_pfn_range() and
vmf_insert_pfn() would allow the zeropage in some cases and
not refcount it.
* vmf_insert_pfn*() will reject the zeropage in VM_MIXEDMAP
mappings and we'll leave that alone for now. People can simply use
one of the other interfaces.
* we won't bother with the huge zeropage for now. It's never
PTE-mapped and also GUP does not special-case it yet.
Link: https://lkml.kernel.org/r/20240522125713.775114-3-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Vincent Donnefort <vdonnefort@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "mm/memory: cleanly support zeropage in vm_insert_page*(),
vm_map_pages*() and vmf_insert_mixed()", v2.
There is interest in mapping zeropages via vm_insert_pages() [1] into
MAP_SHARED mappings.
For now, we only get zeropages in MAP_SHARED mappings via
vmf_insert_mixed() from FSDAX code, and I think it's a bit shaky in some
cases because we refcount the zeropage when mapping it but not necessarily
always when unmapping it ... and we should actually never refcount it.
It's all a bit tricky, especially how zeropages in MAP_SHARED mappings
interact with GUP (FOLL_LONGTERM), mprotect(), write-faults and s390x
forbidding the shared zeropage (rewrite [2] s now upstream).
This series tries to take the careful approach of only allowing the
zeropage where it is likely safe to use (which should cover the existing
FSDAX use case and [1]), preventing that it could accidentally get mapped
writable during a write fault, mprotect() etc, and preventing issues with
FOLL_LONGTERM in the future with other users.
Tested with a patch from Vincent that uses the zeropage in context of
[1].
[1] https://lkml.kernel.org/r/20240430111354.637356-1-vdonnefort@google.com
[2] https://lkml.kernel.org/r/20240411161441.910170-1-david@redhat.com
This patch (of 3):
We'll now also cover the case where insert_page() is called from
__vm_insert_mixed(), which sounds like the right thing to do.
Link: https://lkml.kernel.org/r/20240522125713.775114-2-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Vincent Donnefort <vdonnefort@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
All users have been converted to use the folio version of these macros, we
can safely remove the page based interface.
Link: https://lkml.kernel.org/r/20240520224407.110062-1-sidhartha.kumar@oracle.com
Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Peter Xu <peterx@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Currently we use one swap_address_space for every 64M chunk to reduce lock
contention, this is like having a set of smaller swap files inside one
swap device. But when doing swap cache look up or insert, we are still
using the offset of the whole large swap device. This is OK for
correctness, as the offset (key) is unique.
But Xarray is specially optimized for small indexes, it creates the radix
tree levels lazily to be just enough to fit the largest key stored in one
Xarray. So we are wasting tree nodes unnecessarily.
For 64M chunk it should only take at most 3 levels to contain everything.
But if we are using the offset from the whole swap device, the offset
(key) value will be way beyond 64M, and so will the tree level.
Optimize this by using a new helper swap_cache_index to get a swap entry's
unique offset in its own 64M swap_address_space.
I see a ~1% performance gain in benchmark and actual workload with high
memory pressure.
Test with `time memhog 128G` inside a 8G memcg using 128G swap (ramdisk
with SWP_SYNCHRONOUS_IO dropped, tested 3 times, results are stable. The
test result is similar but the improvement is smaller if
SWP_SYNCHRONOUS_IO is enabled, as swap out path can never skip swap
cache):
Before:
6.07user 250.74system 4:17.26elapsed 99%CPU (0avgtext+0avgdata 8373376maxresident)k
0inputs+0outputs (55major+33555018minor)pagefaults 0swaps
After (1.8% faster):
6.08user 246.09system 4:12.58elapsed 99%CPU (0avgtext+0avgdata 8373248maxresident)k
0inputs+0outputs (54major+33555027minor)pagefaults 0swaps
Similar result with MySQL and sysbench using swap:
Before:
94055.61 qps
After (0.8% faster):
94834.91 qps
Radix tree slab usage is also very slightly lower.
Link: https://lkml.kernel.org/r/20240521175854.96038-12-ryncsn@gmail.com
Signed-off-by: Kairui Song <kasong@tencent.com>
Reviewed-by: "Huang, Ying" <ying.huang@intel.com>
Cc: Anna Schumaker <anna@kernel.org>
Cc: Barry Song <v-songbaohua@oppo.com>
Cc: Chao Yu <chao@kernel.org>
Cc: Chris Li <chrisl@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ilya Dryomov <idryomov@gmail.com>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: Jeff Layton <jlayton@kernel.org>
Cc: Marc Dionne <marc.dionne@auristor.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: NeilBrown <neilb@suse.de>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Cc: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: Xiubo Li <xiubli@redhat.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
There are two helpers for retrieving the index within address space for
mixed usage of swap cache and page cache:
- page_index
- folio_index
This commit drops page_index, as we have eliminated all users, and
converts folio_index's helper __page_file_index to use folio to avoid the
page conversion.
Link: https://lkml.kernel.org/r/20240521175854.96038-11-ryncsn@gmail.com
Signed-off-by: Kairui Song <kasong@tencent.com>
Reviewed-by: "Huang, Ying" <ying.huang@intel.com>
Cc: Anna Schumaker <anna@kernel.org>
Cc: Barry Song <v-songbaohua@oppo.com>
Cc: Chao Yu <chao@kernel.org>
Cc: Chris Li <chrisl@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ilya Dryomov <idryomov@gmail.com>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: Jeff Layton <jlayton@kernel.org>
Cc: Marc Dionne <marc.dionne@auristor.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: NeilBrown <neilb@suse.de>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Cc: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: Xiubo Li <xiubli@redhat.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
These two helpers were useful for mixed usage of swap cache and page
cache, which help retrieve the corresponding file or swap device offset of
a page or folio.
They were introduced in commit f981c5950f ("mm: methods for teaching
filesystems about PG_swapcache pages") and used in commit d56b4ddf77
("nfs: teach the NFS client how to treat PG_swapcache pages"), suppose to
be used with direct_IO for swap over fs.
But after commit e1209d3a7a ("mm: introduce ->swap_rw and use it for
reads from SWP_FS_OPS swap-space"), swap with direct_IO is no more, and
swap cache mapping is never exposed to fs.
Now we have dropped all users of page_file_offset and folio_file_pos, so
they can be deleted.
Link: https://lkml.kernel.org/r/20240521175854.96038-10-ryncsn@gmail.com
Signed-off-by: Kairui Song <kasong@tencent.com>
Reviewed-by: "Huang, Ying" <ying.huang@intel.com>
Cc: Anna Schumaker <anna@kernel.org>
Cc: Barry Song <v-songbaohua@oppo.com>
Cc: Chao Yu <chao@kernel.org>
Cc: Chris Li <chrisl@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ilya Dryomov <idryomov@gmail.com>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: Jeff Layton <jlayton@kernel.org>
Cc: Marc Dionne <marc.dionne@auristor.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: NeilBrown <neilb@suse.de>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Cc: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: Xiubo Li <xiubli@redhat.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
folio_file_pos and page_file_offset are for mixed usage of swap cache and
page cache, it can't be page cache here, so introduce a new helper to get
the swap offset in swap device directly.
Need to include swapops.h in mm/swap.h to ensure swp_offset is always
defined before use.
Link: https://lkml.kernel.org/r/20240521175854.96038-9-ryncsn@gmail.com
Signed-off-by: Kairui Song <kasong@tencent.com>
Reviewed-by: "Huang, Ying" <ying.huang@intel.com>
Cc: Anna Schumaker <anna@kernel.org>
Cc: Barry Song <v-songbaohua@oppo.com>
Cc: Chao Yu <chao@kernel.org>
Cc: Chris Li <chrisl@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ilya Dryomov <idryomov@gmail.com>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: Jeff Layton <jlayton@kernel.org>
Cc: Marc Dionne <marc.dionne@auristor.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: NeilBrown <neilb@suse.de>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Cc: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: Xiubo Li <xiubli@redhat.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
folio_file_pos is only needed for mixed usage of page cache and swap
cache, for pure page cache usage, the caller can just use folio_pos
instead.
After commit e1209d3a7a ("mm: introduce ->swap_rw and use it for reads
from SWP_FS_OPS swap-space"), swap cache should never be exposed to nfs.
So remove the usage of folio_file_pos in following NFS functions / helpers:
- nfs_vm_page_mkwrite
It's only used by nfs_file_vm_ops.page_mkwrite
- trace event helper: nfs_folio_event
- trace event helper: nfs_folio_event_done
These two are used through DEFINE_NFS_FOLIO_EVENT and
DEFINE_NFS_FOLIO_EVENT_DONE, which defined following events:
- trace_nfs_aop_readpage{_done}: only called by nfs_read_folio
- trace_nfs_writeback_folio: only called by nfs_wb_folio
- trace_nfs_invalidate_folio: only called by nfs_invalidate_folio
- trace_nfs_launder_folio_done: only called by nfs_launder_folio
None of them could possibly be used on swap cache folio,
nfs_read_folio only called by:
.write_begin -> nfs_read_folio
.read_folio
nfs_wb_folio only called by nfs mapping:
.release_folio -> nfs_wb_folio
.launder_folio -> nfs_wb_folio
.write_begin -> nfs_read_folio -> nfs_wb_folio
.read_folio -> nfs_wb_folio
.write_end -> nfs_update_folio -> nfs_writepage_setup -> nfs_setup_write_request -> nfs_try_to_update_request -> nfs_wb_folio
.page_mkwrite -> nfs_update_folio -> nfs_writepage_setup -> nfs_setup_write_request -> nfs_try_to_update_request -> nfs_wb_folio
.write_begin -> nfs_flush_incompatible -> nfs_wb_folio
.page_mkwrite -> nfs_vm_page_mkwrite -> nfs_flush_incompatible -> nfs_wb_folio
nfs_invalidate_folio is only called by .invalidate_folio.
nfs_launder_folio is only called by .launder_folio
- nfs_grow_file
- nfs_update_folio
nfs_grow_file is only called by nfs_update_folio, and all
possible callers of them are:
.write_end -> nfs_update_folio
.page_mkwrite -> nfs_update_folio
- nfs_wb_folio_cancel
.invalidate_folio -> nfs_wb_folio_cancel
Also, seeing from the swap side, swap_rw is now the only interface calling
into fs, the offset info is always in iocb.ki_pos now.
So we can remove all these folio_file_pos call safely.
Link: https://lkml.kernel.org/r/20240521175854.96038-8-ryncsn@gmail.com
Signed-off-by: Kairui Song <kasong@tencent.com>
Cc: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: Anna Schumaker <anna@kernel.org>
Cc: Barry Song <v-songbaohua@oppo.com>
Cc: Chao Yu <chao@kernel.org>
Cc: Chris Li <chrisl@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ilya Dryomov <idryomov@gmail.com>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: Jeff Layton <jlayton@kernel.org>
Cc: Marc Dionne <marc.dionne@auristor.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: NeilBrown <neilb@suse.de>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Cc: Xiubo Li <xiubli@redhat.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
folio_file_pos is only needed for mixed usage of page cache and swap
cache, for pure page cache usage, the caller can just use folio_pos
instead.
It can't be a swap cache page here. Swap mapping may only call into fs
through swap_rw and that is not supported for netfs. So just drop it and
use folio_pos instead.
Link: https://lkml.kernel.org/r/20240521175854.96038-7-ryncsn@gmail.com
Signed-off-by: Kairui Song <kasong@tencent.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Jeff Layton <jlayton@kernel.org>
Cc: Anna Schumaker <anna@kernel.org>
Cc: Barry Song <v-songbaohua@oppo.com>
Cc: Chao Yu <chao@kernel.org>
Cc: Chris Li <chrisl@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ilya Dryomov <idryomov@gmail.com>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: Marc Dionne <marc.dionne@auristor.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: NeilBrown <neilb@suse.de>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Cc: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: Xiubo Li <xiubli@redhat.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
folio_file_pos is only needed for mixed usage of page cache and swap
cache, for pure page cache usage, the caller can just use folio_pos
instead.
It can't be a swap cache page here. Swap mapping may only call into fs
through swap_rw and that is not supported for afs. So just drop it and
use folio_pos instead.
Link: https://lkml.kernel.org/r/20240521175854.96038-6-ryncsn@gmail.com
Signed-off-by: Kairui Song <kasong@tencent.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Marc Dionne <marc.dionne@auristor.com>
Cc: Anna Schumaker <anna@kernel.org>
Cc: Barry Song <v-songbaohua@oppo.com>
Cc: Chao Yu <chao@kernel.org>
Cc: Chris Li <chrisl@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ilya Dryomov <idryomov@gmail.com>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: Jeff Layton <jlayton@kernel.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: NeilBrown <neilb@suse.de>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Cc: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: Xiubo Li <xiubli@redhat.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This function is no longer used after commit 4fa7a717b4 ("NFS: Fix up
nfs_vm_page_mkwrite() for folios"), all users have been converted to use
folio instead, just delete it to remove usage of page_index.
Link: https://lkml.kernel.org/r/20240521175854.96038-5-ryncsn@gmail.com
Signed-off-by: Kairui Song <kasong@tencent.com>
Cc: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: Anna Schumaker <anna@kernel.org>
Cc: Barry Song <v-songbaohua@oppo.com>
Cc: Chao Yu <chao@kernel.org>
Cc: Chris Li <chrisl@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ilya Dryomov <idryomov@gmail.com>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: Jeff Layton <jlayton@kernel.org>
Cc: Marc Dionne <marc.dionne@auristor.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: NeilBrown <neilb@suse.de>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Cc: Xiubo Li <xiubli@redhat.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
page_index is needed for mixed usage of page cache and swap cache, for
pure page cache usage, the caller can just use page->index instead.
It can't be a swap cache page here, so just drop it.
Link: https://lkml.kernel.org/r/20240521175854.96038-4-ryncsn@gmail.com
Signed-off-by: Kairui Song <kasong@tencent.com>
Cc: Xiubo Li <xiubli@redhat.com>
Cc: Ilya Dryomov <idryomov@gmail.com>
Cc: Jeff Layton <jlayton@kernel.org>
Cc: Anna Schumaker <anna@kernel.org>
Cc: Barry Song <v-songbaohua@oppo.com>
Cc: Chao Yu <chao@kernel.org>
Cc: Chris Li <chrisl@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: Marc Dionne <marc.dionne@auristor.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: NeilBrown <neilb@suse.de>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Cc: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "mm/swap: clean up and optimize swap cache index", v6.
Currently we use one swap_address_space for every 64M chunk to reduce lock
contention, this is like having a set of smaller files inside a swap
device. But when doing swap cache look up or insert, we are still using
the offset of the whole large swap device. This is OK for correctness, as
the offset (key) is unique.
But Xarray is specially optimized for small indexes, it creates the redix
tree levels lazily to be just enough to fit the largest key stored in one
Xarray. So we are wasting tree nodes unnecessarily.
For 64M chunk it should only take at most 3 level to contain everything.
But if we are using the offset from the whole swap device, the offset
(key) value will be way beyond 64M, and so will the tree level.
Optimize this by reduce the swap cache search space into 64M scope.
Test with `time memhog 128G` inside a 8G memcg using 128G swap (ramdisk
with SWP_SYNCHRONOUS_IO dropped, tested 3 times, results are stable. The
test result is similar but the improvement is smaller if
SWP_SYNCHRONOUS_IO is enabled, as swap out path can never skip swap
cache):
Before:
6.07user 250.74system 4:17.26elapsed 99%CPU (0avgtext+0avgdata 8373376maxresident)k
0inputs+0outputs (55major+33555018minor)pagefaults 0swaps
After (+1.8% faster):
6.08user 246.09system 4:12.58elapsed 99%CPU (0avgtext+0avgdata 8373248maxresident)k
0inputs+0outputs (54major+33555027minor)pagefaults 0swaps
Similar result with MySQL and sysbench using swap:
Before:
94055.61 qps
After (+0.8% faster):
94834.91 qps
There is alse a very slight drop of radix tree node slab usage:
Before: 303952K
After: 302224K
For this series:
There are multiple places that expect mixed type of pages (page cache or
swap cache), eg. migration, huge memory split; There are four helpers
for that:
- page_index
- page_file_offset
- folio_index
- folio_file_pos
To keep the code clean and compatible, this series first cleaned up usage
of them.
page_file_offset and folio_file_pos are historical helpes that can be
simply dropped after clean up. And page_index can be all converted to
folio_index or folio->index.
Then introduce two new helpers swap_cache_index and swap_dev_pos for swap.
Replace swp_offset with swap_cache_index when used to retrieve folio from
swap cache, and use swap_dev_pos when needed to retrieve the device
position of a swap entry. This way, swap_cache_index can return the
optimized value with no compatibility issue.
The result is better performance and reduced LOC.
Idealy, in the future, we may want to reduce SWAP_ADDRESS_SPACE_SHIFT from
14 to 12: Default Xarray chunk offset is 6, so we have 3 level trees
instead of 2 level trees just for 2 extra bits. But swap cache is based
on address_space struct, with 4 times more metadata sparsely distributed
in memory it waste more cacheline, the performance gain from this series
is almost canceled according to my test. So first, just have a cleaner
seperation of offsets and smaller search space.
This patch (of 10):
page_index is only for mixed usage of page cache and swap cache, for pure
page cache usage, the caller can just use page->index instead.
It can't be a swap cache page here (being part of buffer head), so just
drop it. And while we are at it, optimize the code by retrieving the
offset of the buffer head within the folio directly using bh_offset, and
get rid of the loop and usage of page helpers.
Link: https://lkml.kernel.org/r/20240521175854.96038-1-ryncsn@gmail.com
Link: https://lkml.kernel.org/r/20240521175854.96038-3-ryncsn@gmail.com
Suggested-by: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Kairui Song <kasong@tencent.com>
Acked-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Cc: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Cc: Anna Schumaker <anna@kernel.org>
Cc: Barry Song <v-songbaohua@oppo.com>
Cc: Chao Yu <chao@kernel.org>
Cc: Chris Li <chrisl@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ilya Dryomov <idryomov@gmail.com>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: Jeff Layton <jlayton@kernel.org>
Cc: Marc Dionne <marc.dionne@auristor.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: NeilBrown <neilb@suse.de>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: Xiubo Li <xiubli@redhat.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Factor out wb_dirty_freerun to remove more repeated freerun code.
Link: https://lkml.kernel.org/r/20240514125254.142203-6-shikemeng@huaweicloud.com
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Factor out code of freerun into new helper functions domain_poll_intv and
domain_dirty_freerun to remove repeated code.
Link: https://lkml.kernel.org/r/20240514125254.142203-5-shikemeng@huaweicloud.com
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Factor out domain_over_bg_thresh from wb_over_bg_thresh to remove repeated
code.
Link: https://lkml.kernel.org/r/20240514125254.142203-4-shikemeng@huaweicloud.com
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Add general function domain_dirty_avail to calculate dirty and avail for
either dirty limit or background writeback in either global domain or wb
domain.
Link: https://lkml.kernel.org/r/20240514125254.142203-3-shikemeng@huaweicloud.com
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "Add helper functions to remove repeated code and improve
readability of cgroup writeback", v2.
This series adds a lot of helpers to remove repeated code between domain
and wb; dirty limit and dirty background; global domain and wb domain.
The helpers also improve readability. More details can be found in the
respective patches.
A simple domain hierarchy is tested:
global domain (> 20G)
|
cgroup domain1(10G)
|
wb1
|
fio
Test steps:
/* make it easy to observe */
echo 300000 > /proc/sys/vm/dirty_expire_centisecs
echo 3000 > /proc/sys/vm/dirty_writeback_centisecs
/* create cgroup domain */
cd /sys/fs/cgroup
echo "+memory +io" > cgroup.subtree_control
mkdir group1
cd group1
echo 10G > memory.high
echo 10G > memory.max
echo $$ > cgroup.procs
mkfs.ext4 -F /dev/vdb
mount /dev/vdb /bdi1/
/* run fio to generate dirty pages */
fio -name test -filename=/bdi1/file -size=xxx -ioengine=libaio -bs=4K \
-iodepth=1 -rw=write -direct=0 --time_based -runtime=600 -invalidate=0
When fio size is 1G, the wb is in freerun state and dirty pages are only
written back when dirty inode is expired after 30 seconds. When fio size
is 2G, the dirty pages keep being written back and bandwidth of fio is
limited.
This patch (of 8):
Similar to wb_dirty_limits which calculates dirty and thresh of wb,
wb_bg_dirty_limits calculates background dirty and background thresh of
wb. With wb_bg_dirty_limits, we could remove repeated code in
wb_over_bg_thresh.
Link: https://lkml.kernel.org/r/20240514125254.142203-1-shikemeng@huaweicloud.com
Link: https://lkml.kernel.org/r/20240514125254.142203-2-shikemeng@huaweicloud.com
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Currently, reclaim always walks the entire cgroup tree in order to ensure
fairness between groups. While overreclaim is limited in shrink_lruvec(),
many of our systems have a sizable number of active groups, and an even
bigger number of idle cgroups with cache left behind by previous jobs; the
mere act of walking all these cgroups can impose significant latency on
direct reclaimers.
In the past, we've used a save-and-restore iterator that enabled
incremental tree walks over multiple reclaim invocations. This ensured
fairness, while keeping the work of individual reclaimers small.
However, in edge cases with a lot of reclaim concurrency, individual
reclaimers would sometimes not see enough of the cgroup tree to make
forward progress and (prematurely) declare OOM. Consequently we switched
to comprehensive walks in 1ba6fc9af3 ("mm: vmscan: do not share cgroup
iteration between reclaimers").
To address the latency problem without bringing back the premature OOM
issue, reinstate the shared iteration, but with a restart condition to do
the full walk in the OOM case - similar to what we do for memory.low
enforcement and active page protection.
In the worst case, we do one more full tree walk before declaring
OOM. But the vast majority of direct reclaim scans can then finish
much quicker, while fairness across the tree is maintained:
- Before this patch, we observed that direct reclaim always takes more
than 100us and most direct reclaim time is spent in reclaim cycles
lasting between 1ms and 1 second. Almost 40% of direct reclaim time
was spent on reclaim cycles exceeding 100ms.
- With this patch, almost all page reclaim cycles last less than 10ms,
and a good amount of direct page reclaim finishes in under 100us. No
page reclaim cycles lasting over 100ms were observed anymore.
The shared iterator state is maintaned inside the target cgroup, so
fair and incremental walks are performed during both global reclaim
and cgroup limit reclaim of complex subtrees.
Link: https://lkml.kernel.org/r/20240514202641.2821494-1-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Rik van Riel <riel@surriel.com>
Reported-by: Rik van Riel <riel@surriel.com>
Reviewed-by: Shakeel Butt <shakeel.butt@linux.dev>
Reviewed-by: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Facebook Kernel Team <kernel-team@fb.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Rik van Riel <riel@surriel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
huge_anon_orders_always is accessed lockless, it is better to use the
READ_ONCE() wrapper. This is not fixing any visible bug, hopefully this
can cease some KCSAN complains in the future. Also do that for
huge_anon_orders_madvise.
Link: https://lkml.kernel.org/r/20240515104754889HqrahFPePOIE1UlANHVAh@zte.com.cn
Signed-off-by: Ran Xiaokai <ran.xiaokai@zte.com.cn>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Lu Zhongjun <lu.zhongjun@zte.com.cn>
Reviewed-by: xu xin <xu.xin16@zte.com.cn>
Cc: Yang Yang <yang.yang29@zte.com.cn>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Let's change shmem_alloc_folio() to take a order and use
folio_alloc_mpol() helper, then directly use it for normal or large folio
to cleanup code.
Link: https://lkml.kernel.org/r/20240515070709.78529-5-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Convert to use folio_alloc_mpol() to make vma_alloc_folio_noprof() to use
folio throughout.
Link: https://lkml.kernel.org/r/20240515070709.78529-4-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Convert to use folio_alloc_mpol_noprof() to make vma_alloc_folio_noprof()
to use folio throughout.
Link: https://lkml.kernel.org/r/20240515070709.78529-3-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
