The CONFIG_EXPERIMENTAL config item has not carried much meaning for a
while now and is almost always enabled by default. As agreed during the
Linux kernel summit, remove it from any "depends on" lines in Kconfigs.
CC: Andrew Morton <akpm@linux-foundation.org>
CC: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
CC: Jan Beulich <JBeulich@novell.com>
CC: Mel Gorman <mel@csn.ul.ie>
CC: Seth Jennings <sjenning@linux.vnet.ibm.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Add help info for CONFIG_MOVABLE_NODE and permit its selection.
This option allows the user to online all memory of a node as movable
memory. So that the whole node can be hotplugged. Users who don't use
the hotplug feature are also fine with this option on since they won't
online memory as movable.
Signed-off-by: Tang Chen <tangchen@cn.fujitsu.com>
Reviewed-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Wen Congyang <wency@cn.fujitsu.com>
Cc: Ingo Molnar <mingo@elte.hu>
[akpm@linux-foundation.org: tweak help text]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Merge misc VM changes from Andrew Morton:
"The rest of most-of-MM. The other MM bits await a slab merge.
This patch includes the addition of a huge zero_page. Not a
performance boost but it an save large amounts of physical memory in
some situations.
Also a bunch of Fujitsu engineers are working on memory hotplug.
Which, as it turns out, was badly broken. About half of their patches
are included here; the remainder are 3.8 material."
However, this merge disables CONFIG_MOVABLE_NODE, which was totally
broken. We don't add new features with "default y", nor do we add
Kconfig questions that are incomprehensible to most people without any
help text. Does the feature even make sense without compaction or
memory hotplug?
* akpm: (54 commits)
mm/bootmem.c: remove unused wrapper function reserve_bootmem_generic()
mm/memory.c: remove unused code from do_wp_page()
asm-generic, mm: pgtable: consolidate zero page helpers
mm/hugetlb.c: fix warning on freeing hwpoisoned hugepage
hwpoison, hugetlbfs: fix RSS-counter warning
hwpoison, hugetlbfs: fix "bad pmd" warning in unmapping hwpoisoned hugepage
mm: protect against concurrent vma expansion
memcg: do not check for mm in __mem_cgroup_count_vm_event
tmpfs: support SEEK_DATA and SEEK_HOLE (reprise)
mm: provide more accurate estimation of pages occupied by memmap
fs/buffer.c: remove redundant initialization in alloc_page_buffers()
fs/buffer.c: do not inline exported function
writeback: fix a typo in comment
mm: introduce new field "managed_pages" to struct zone
mm, oom: remove statically defined arch functions of same name
mm, oom: remove redundant sleep in pagefault oom handler
mm, oom: cleanup pagefault oom handler
memory_hotplug: allow online/offline memory to result movable node
numa: add CONFIG_MOVABLE_NODE for movable-dedicated node
mm, memcg: avoid unnecessary function call when memcg is disabled
...
We need a node which only contains movable memory. This feature is very
important for node hotplug. If a node has normal/highmem, the memory may
be used by the kernel and can't be offlined. If the node only contains
movable memory, we can offline the memory and the node.
All are prepared, we can actually introduce N_MEMORY.
add CONFIG_MOVABLE_NODE make we can use it for movable-dedicated node
[akpm@linux-foundation.org: fix Kconfig text]
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Tested-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
Cc: Jiang Liu <jiang.liu@huawei.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: David Rientjes <rientjes@google.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Memory fragmentation introduced by ballooning might reduce significantly
the number of 2MB contiguous memory blocks that can be used within a guest,
thus imposing performance penalties associated with the reduced number of
transparent huge pages that could be used by the guest workload.
This patch introduces a common interface to help a balloon driver on
making its page set movable to compaction, and thus allowing the system
to better leverage the compation efforts on memory defragmentation.
[akpm@linux-foundation.org: use PAGE_FLAGS_CHECK_AT_PREP, s/__balloon_page_flags/page_flags_cleared/, small cleanups]
[rientjes@google.com: allow balloon compaction for any system with memory compaction enabled, which is the defconfig]
Signed-off-by: Rafael Aquini <aquini@redhat.com>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Now that lumpy reclaim has been removed, compaction is the only way left
to free up contiguous memory areas. It is time to just enable
CONFIG_COMPACTION by default.
Signed-off-by: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Acked-by: Rafael Aquini <aquini@redhat.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Cleanup patch in preparation for transparent hugepage support on s390.
Adding new architectures to the TRANSPARENT_HUGEPAGE config option can
make the "depends" line rather ugly, like "depends on (X86 || (S390 &&
64BIT)) && MMU".
This patch adds a HAVE_ARCH_TRANSPARENT_HUGEPAGE instead. x86 already has
MMU "def_bool y", so the MMU check is superfluous there and
HAVE_ARCH_TRANSPARENT_HUGEPAGE can be selected in arch/x86/Kconfig.
Signed-off-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Hillf Danton <dhillf@gmail.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm/page_alloc.c has some memory isolation functions but they are used only
when we enable CONFIG_{CMA|MEMORY_HOTPLUG|MEMORY_FAILURE}. So let's make
it configurable by new CONFIG_MEMORY_ISOLATION so that it can reduce
binary size and we can check it simple by CONFIG_MEMORY_ISOLATION, not if
defined CONFIG_{CMA|MEMORY_HOTPLUG|MEMORY_FAILURE}.
Signed-off-by: Minchan Kim <minchan@kernel.org>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In some environments, dramatic performance savings may be obtained because
swapped pages are saved in RAM (or a RAM-like device) instead of a swap disk.
This tag provides the basic infrastructure along with some changes to the
existing backends.
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Merge tag 'stable/frontswap.v16-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/mm
Pull frontswap feature from Konrad Rzeszutek Wilk:
"Frontswap provides a "transcendent memory" interface for swap pages.
In some environments, dramatic performance savings may be obtained
because swapped pages are saved in RAM (or a RAM-like device) instead
of a swap disk. This tag provides the basic infrastructure along with
some changes to the existing backends."
Fix up trivial conflict in mm/Makefile due to removal of swap token code
changing a line next to the new frontswap entry.
This pull request came in before the merge window even opened, it got
delayed to after the merge window by me just wanting to make sure it had
actual users. Apparently IBM is using this on their embedded side, and
Jan Beulich says that it's already made available for SLES and OpenSUSE
users.
Also acked by Rik van Riel, and Konrad points to other people liking it
too. So in it goes.
By Dan Magenheimer (4) and Konrad Rzeszutek Wilk (2)
via Konrad Rzeszutek Wilk
* tag 'stable/frontswap.v16-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/mm:
frontswap: s/put_page/store/g s/get_page/load
MAINTAINER: Add myself for the frontswap API
mm: frontswap: config and doc files
mm: frontswap: core frontswap functionality
mm: frontswap: core swap subsystem hooks and headers
mm: frontswap: add frontswap header file
Add a Kconfig option to allow people who don't want cross memory attach to
not have it included in their build.
Signed-off-by: Chris Yeoh <yeohc@au1.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The MIGRATE_CMA migration type has two main characteristics:
(i) only movable pages can be allocated from MIGRATE_CMA
pageblocks and (ii) page allocator will never change migration
type of MIGRATE_CMA pageblocks.
This guarantees (to some degree) that page in a MIGRATE_CMA page
block can always be migrated somewhere else (unless there's no
memory left in the system).
It is designed to be used for allocating big chunks (eg. 10MiB)
of physically contiguous memory. Once driver requests
contiguous memory, pages from MIGRATE_CMA pageblocks may be
migrated away to create a contiguous block.
To minimise number of migrations, MIGRATE_CMA migration type
is the last type tried when page allocator falls back to other
migration types when requested.
Signed-off-by: Michal Nazarewicz <mina86@mina86.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Tested-by: Rob Clark <rob.clark@linaro.org>
Tested-by: Ohad Ben-Cohen <ohad@wizery.com>
Tested-by: Benjamin Gaignard <benjamin.gaignard@linaro.org>
Tested-by: Robert Nelson <robertcnelson@gmail.com>
Tested-by: Barry Song <Baohua.Song@csr.com>
This patch 4of4 adds configuration and documentation files including a FAQ.
[v14: updated docs/FAQ to use zcache and RAMster as examples]
[v10: no change]
[v9: akpm@linux-foundation.org: sysfs->debugfs; no longer need Doc/ABI file]
[v8: rebase to 3.0-rc4]
[v7: rebase to 3.0-rc3]
[v6: rebase to 3.0-rc1]
[v5: change config default to n]
[v4: rebase to 2.6.39]
Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com>
Acked-by: Jan Beulich <JBeulich@novell.com>
Acked-by: Seth Jennings <sjenning@linux.vnet.ibm.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Matthew Wilcox <matthew@wil.cx>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Rik Riel <riel@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Conflicts & resolutions:
* arch/x86/xen/setup.c
dc91c728fd "xen: allow extra memory to be in multiple regions"
24aa07882b "memblock, x86: Replace memblock_x86_reserve/free..."
conflicted on xen_add_extra_mem() updates. The resolution is
trivial as the latter just want to replace
memblock_x86_reserve_range() with memblock_reserve().
* drivers/pci/intel-iommu.c
166e9278a3 "x86/ia64: intel-iommu: move to drivers/iommu/"
5dfe8660a3 "bootmem: Replace work_with_active_regions() with..."
conflicted as the former moved the file under drivers/iommu/.
Resolved by applying the chnages from the latter on the moved
file.
* mm/Kconfig
6661672053 "memblock: add NO_BOOTMEM config symbol"
c378ddd53f "memblock, x86: Make ARCH_DISCARD_MEMBLOCK a config option"
conflicted trivially. Both added config options. Just
letting both add their own options resolves the conflict.
* mm/memblock.c
d1f0ece6cd "mm/memblock.c: small function definition fixes"
ed7b56a799 "memblock: Remove memblock_memory_can_coalesce()"
confliected. The former updates function removed by the
latter. Resolution is trivial.
Signed-off-by: Tejun Heo <tj@kernel.org>
With the NO_BOOTMEM symbol added architectures may now use the following
syntax to tell that they do not need bootmem:
select NO_BOOTMEM
This is much more convinient than adding a new kconfig symbol which was
otherwise required.
Adding this symbol does not conflict with the architctures that already
define their own symbol.
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
From 6839454ae63f1eb21e515c10229ca95c22955fec Mon Sep 17 00:00:00 2001
From: Tejun Heo <tj@kernel.org>
Date: Thu, 14 Jul 2011 11:22:17 +0200
Make ARCH_DISCARD_MEMBLOCK a config option so that it can be handled
together with other MEMBLOCK options.
Signed-off-by: Tejun Heo <tj@kernel.org>
Link: http://lkml.kernel.org/r/20110714094603.GH3455@htj.dyndns.org
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
From 83103b92f3234ec830852bbc5c45911bd6cbdb20 Mon Sep 17 00:00:00 2001
From: Tejun Heo <tj@kernel.org>
Date: Thu, 14 Jul 2011 11:22:16 +0200
Add optional region->nid which can be enabled by arch using
CONFIG_HAVE_MEMBLOCK_NODE_MAP. When enabled, memblock also carries
NUMA node information and replaces early_node_map[].
Newly added memblocks have MAX_NUMNODES as nid. Arch can then call
memblock_set_node() to set node information. memblock takes care of
merging and node affine allocations w.r.t. node information.
When MEMBLOCK_NODE_MAP is enabled, early_node_map[], related data
structures and functions to manipulate and iterate it are disabled.
memblock version of __next_mem_pfn_range() is provided such that
for_each_mem_pfn_range() behaves the same and its users don't have to
be updated.
-v2: Yinghai spotted section mismatch caused by missing
__init_memblock in memblock_set_node(). Fixed.
Signed-off-by: Tejun Heo <tj@kernel.org>
Link: http://lkml.kernel.org/r/20110714094342.GF3455@htj.dyndns.org
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
This third patch of eight in this cleancache series provides
the core code for cleancache that interfaces between the hooks in
VFS and individual filesystems and a cleancache backend. It also
includes build and config patches.
Two new files are added: mm/cleancache.c and include/linux/cleancache.h.
Note that CONFIG_CLEANCACHE can default to on; in systems that do
not provide a cleancache backend, all hooks devolve to a simple
check of a global enable flag, so performance impact should
be negligible but can be reduced to zero impact if config'ed off.
However for this first commit, it defaults to off.
Details and a FAQ can be found in Documentation/vm/cleancache.txt
Credits: Cleancache_ops design derived from Jeremy Fitzhardinge
design for tmem
[v8: dan.magenheimer@oracle.com: fix exportfs call affecting btrfs]
[v8: akpm@linux-foundation.org: use static inline function, not macro]
[v7: dan.magenheimer@oracle.com: cleanup sysfs and remove cleancache prefix]
[v6: JBeulich@novell.com: robustly handle buggy fs encode_fh actor definition]
[v5: jeremy@goop.org: clean up global usage and static var names]
[v5: jeremy@goop.org: simplify init hook and any future fs init changes]
[v5: hch@infradead.org: cleaner non-global interface for ops registration]
[v4: adilger@sun.com: interface must support exportfs FS's]
[v4: hch@infradead.org: interface must support 64-bit FS on 32-bit kernel]
[v3: akpm@linux-foundation.org: use one ops struct to avoid pointer hops]
[v3: akpm@linux-foundation.org: document and ensure PageLocked reqts are met]
[v3: ngupta@vflare.org: fix success/fail codes, change funcs to void]
[v2: viro@ZenIV.linux.org.uk: use sane types]
Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com>
Reviewed-by: Jeremy Fitzhardinge <jeremy@goop.org>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: Al Viro <viro@ZenIV.linux.org.uk>
Acked-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Nitin Gupta <ngupta@vflare.org>
Acked-by: Minchan Kim <minchan.kim@gmail.com>
Acked-by: Andreas Dilger <adilger@sun.com>
Acked-by: Jan Beulich <JBeulich@novell.com>
Cc: Matthew Wilcox <matthew@wil.cx>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Rik Van Riel <riel@redhat.com>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Ted Ts'o <tytso@mit.edu>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <joel.becker@oracle.com>
Commit 5d6892407 ("thp: select CONFIG_COMPACTION if TRANSPARENT_HUGEPAGE
enabled") causes this warning during the configuration process:
warning: (TRANSPARENT_HUGEPAGE) selects COMPACTION which has unmet
direct dependencies (EXPERIMENTAL && HUGETLB_PAGE && MMU)
COMPACTION doesn't depend on HUGETLB_PAGE, it doesn't depend on THP
either, it is also useful for regular alloc_pages(order > 0) including
the very kernel stack during fork (THREAD_ORDER = 1). It's always
better to enable COMPACTION.
The warning should be an error because we would end up with MIGRATION
not selected, and COMPACTION wouldn't work without migration (despite it
seems to build with an inline migrate_pages returning -ENOSYS).
I'd also like to remove EXPERIMENTAL: compaction has been in the kernel
for some releases (for full safety the default remains disabled which I
think is enough).
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Reported-by: Luca Tettamanti <kronos.it@gmail.com>
Tested-by: Luca Tettamanti <kronos.it@gmail.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
With transparent hugepage support we need compaction for the "defrag"
sysfs controls to be effective.
At the moment THP hangs the system if COMPACTION isn't selected, as
without COMPACTION lumpy reclaim wouldn't be entirely disabled. So at the
moment it's not orthogonal. When lumpy will be removed from the VM I can
remove the select COMPACTION in theory, but then 99% of THP users would be
still doing a mistake in disabling compaction, even if the mistake won't
return in fatal runtime but just slightly degraded performance. So from a
theoretical standpoing forcing the below select is not needed (the
dependency isn't strict nor at compile time nor at runtime) but from a
practical standpoint it is safer.
If anybody really wants THP to run without compaction, it'd be such a
weird setup that editing the Kconfig file to allow it will be surely not a
problem.
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Allow to choose between the always|madvise default for page faults and
khugepaged at config time. madvise guarantees zero risk of higher memory
footprint for applications (applications using madvise(MADV_HUGEPAGE)
won't risk to use any more memory by backing their virtual regions with
hugepages).
Initially set the default to N and don't depend on EMBEDDED.
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add support for transparent hugepages to x86 32bit.
Share the same VM_ bitflag for VM_MAPPED_COPY. mm/nommu.c will never
support transparent hugepages.
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu:
percpu: update comments to reflect that percpu allocations are always zero-filled
percpu: Optimize __get_cpu_var()
x86, percpu: Optimize this_cpu_ptr
percpu: clear memory allocated with the km allocator
percpu: fix build breakage on s390 and cleanup build configuration tests
percpu: use percpu allocator on UP too
percpu: reduce PCPU_MIN_UNIT_SIZE to 32k
vmalloc: pcpu_get/free_vm_areas() aren't needed on UP
Fixed up trivial conflicts in include/linux/percpu.h
COMPACTION enables MIGRATION, but MIGRATION spawns a warning if numa or
memhotplug aren't selected. However MIGRATION doesn't depend on them. I
guess it's just trying to be strict doing a double check on who's enabling
it, but it doesn't know that compaction also enables MIGRATION.
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
On UP, percpu allocations were redirected to kmalloc. This has the
following problems.
* For certain amount of allocations (determined by
PERCPU_DYNAMIC_EARLY_SLOTS and PERCPU_DYNAMIC_EARLY_SIZE), percpu
allocator can be used before the usual kernel memory allocator is
brought online. On SMP, this is used to initialize the kernel
memory allocator.
* percpu allocator honors alignment upto PAGE_SIZE but kmalloc()
doesn't. For example, workqueue makes use of larger alignments for
cpu_workqueues.
Currently, users of percpu allocators need to handle UP differently,
which is somewhat fragile and ugly. Other than small amount of
memory, there isn't much to lose by enabling percpu allocator on UP.
It can simply use kernel memory based chunk allocation which was added
for SMP archs w/o MMUs.
This patch removes mm/percpu_up.c, builds mm/percpu.c on UP too and
makes UP build use percpu-km. As percpu addresses and kernel
addresses are always identity mapped and static percpu variables don't
need any special treatment, nothing is arch dependent and mm/percpu.c
implements generic setup_per_cpu_areas() for UP.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Christoph Lameter <cl@linux-foundation.org>
Acked-by: Pekka Enberg <penberg@cs.helsinki.fi>
via following scripts
FILES=$(find * -type f | grep -vE 'oprofile|[^K]config')
sed -i \
-e 's/lmb/memblock/g' \
-e 's/LMB/MEMBLOCK/g' \
$FILES
for N in $(find . -name lmb.[ch]); do
M=$(echo $N | sed 's/lmb/memblock/g')
mv $N $M
done
and remove some wrong change like lmbench and dlmb etc.
also move memblock.c from lib/ to mm/
Suggested-by: Ingo Molnar <mingo@elte.hu>
Acked-by: "H. Peter Anvin" <hpa@zytor.com>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
CONFIG_MIGRATION currently depends on CONFIG_NUMA or on the architecture
being able to hot-remove memory. The main users of page migration such as
sys_move_pages(), sys_migrate_pages() and cpuset process migration are
only beneficial on NUMA so it makes sense.
As memory compaction will operate within a zone and is useful on both NUMA
and non-NUMA systems, this patch allows CONFIG_MIGRATION to be set if the
user selects CONFIG_COMPACTION as an option.
[akpm@linux-foundation.org: Depend on CONFIG_HUGETLB_PAGE]
Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Reviewed-by: Christoph Lameter <cl@linux-foundation.org>
Reviewed-by: Rik van Riel <riel@redhat.com>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'x86-bootmem-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (30 commits)
early_res: Need to save the allocation name in drop_range_partial()
sparsemem: Fix compilation on PowerPC
early_res: Add free_early_partial()
x86: Fix non-bootmem compilation on PowerPC
core: Move early_res from arch/x86 to kernel/
x86: Add find_fw_memmap_area
Move round_up/down to kernel.h
x86: Make 32bit support NO_BOOTMEM
early_res: Enhance check_and_double_early_res
x86: Move back find_e820_area to e820.c
x86: Add find_early_area_size
x86: Separate early_res related code from e820.c
x86: Move bios page reserve early to head32/64.c
sparsemem: Put mem map for one node together.
sparsemem: Put usemap for one node together
x86: Make 64 bit use early_res instead of bootmem before slab
x86: Only call dma32_reserve_bootmem 64bit !CONFIG_NUMA
x86: Make early_node_mem get mem > 4 GB if possible
x86: Dynamically increase early_res array size
x86: Introduce max_early_res and early_res_count
...
Add vmemmap_alloc_block_buf for mem map only.
It will fallback to the old way if it cannot get a block that big.
Before this patch, when a node have 128g ram installed, memmap are
split into two parts or more.
[ 0.000000] [ffffea0000000000-ffffea003fffffff] PMD -> [ffff880100600000-ffff88013e9fffff] on node 1
[ 0.000000] [ffffea0040000000-ffffea006fffffff] PMD -> [ffff88013ec00000-ffff88016ebfffff] on node 1
[ 0.000000] [ffffea0070000000-ffffea007fffffff] PMD -> [ffff882000600000-ffff8820105fffff] on node 0
[ 0.000000] [ffffea0080000000-ffffea00bfffffff] PMD -> [ffff882010800000-ffff8820507fffff] on node 0
[ 0.000000] [ffffea00c0000000-ffffea00dfffffff] PMD -> [ffff882050a00000-ffff8820709fffff] on node 0
[ 0.000000] [ffffea00e0000000-ffffea00ffffffff] PMD -> [ffff884000600000-ffff8840205fffff] on node 2
[ 0.000000] [ffffea0100000000-ffffea013fffffff] PMD -> [ffff884020800000-ffff8840607fffff] on node 2
[ 0.000000] [ffffea0140000000-ffffea014fffffff] PMD -> [ffff884060a00000-ffff8840709fffff] on node 2
[ 0.000000] [ffffea0150000000-ffffea017fffffff] PMD -> [ffff886000600000-ffff8860305fffff] on node 3
[ 0.000000] [ffffea0180000000-ffffea01bfffffff] PMD -> [ffff886030800000-ffff8860707fffff] on node 3
[ 0.000000] [ffffea01c0000000-ffffea01ffffffff] PMD -> [ffff888000600000-ffff8880405fffff] on node 4
[ 0.000000] [ffffea0200000000-ffffea022fffffff] PMD -> [ffff888040800000-ffff8880707fffff] on node 4
[ 0.000000] [ffffea0230000000-ffffea023fffffff] PMD -> [ffff88a000600000-ffff88a0105fffff] on node 5
[ 0.000000] [ffffea0240000000-ffffea027fffffff] PMD -> [ffff88a010800000-ffff88a0507fffff] on node 5
[ 0.000000] [ffffea0280000000-ffffea029fffffff] PMD -> [ffff88a050a00000-ffff88a0709fffff] on node 5
[ 0.000000] [ffffea02a0000000-ffffea02bfffffff] PMD -> [ffff88c000600000-ffff88c0205fffff] on node 6
[ 0.000000] [ffffea02c0000000-ffffea02ffffffff] PMD -> [ffff88c020800000-ffff88c0607fffff] on node 6
[ 0.000000] [ffffea0300000000-ffffea030fffffff] PMD -> [ffff88c060a00000-ffff88c0709fffff] on node 6
[ 0.000000] [ffffea0310000000-ffffea033fffffff] PMD -> [ffff88e000600000-ffff88e0305fffff] on node 7
[ 0.000000] [ffffea0340000000-ffffea037fffffff] PMD -> [ffff88e030800000-ffff88e0707fffff] on node 7
after patch will get
[ 0.000000] [ffffea0000000000-ffffea006fffffff] PMD -> [ffff880100200000-ffff88016e5fffff] on node 0
[ 0.000000] [ffffea0070000000-ffffea00dfffffff] PMD -> [ffff882000200000-ffff8820701fffff] on node 1
[ 0.000000] [ffffea00e0000000-ffffea014fffffff] PMD -> [ffff884000200000-ffff8840701fffff] on node 2
[ 0.000000] [ffffea0150000000-ffffea01bfffffff] PMD -> [ffff886000200000-ffff8860701fffff] on node 3
[ 0.000000] [ffffea01c0000000-ffffea022fffffff] PMD -> [ffff888000200000-ffff8880701fffff] on node 4
[ 0.000000] [ffffea0230000000-ffffea029fffffff] PMD -> [ffff88a000200000-ffff88a0701fffff] on node 5
[ 0.000000] [ffffea02a0000000-ffffea030fffffff] PMD -> [ffff88c000200000-ffff88c0701fffff] on node 6
[ 0.000000] [ffffea0310000000-ffffea037fffffff] PMD -> [ffff88e000200000-ffff88e0701fffff] on node 7
-v2: change buf to vmemmap_buf instead according to Ingo
also add CONFIG_SPARSEMEM_ALLOC_MEM_MAP_TOGETHER according to Ingo
-v3: according to Andrew, use sizeof(name) instead of hard coded 15
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
LKML-Reference: <1265793639-15071-19-git-send-email-yinghai@kernel.org>
Cc: Christoph Lameter <cl@linux-foundation.org>
Acked-by: Christoph Lameter <cl@linux-foundation.org>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
We previously had 2 quicklists, one for the PGD case and one for PTEs.
Now that the PGD/PMD cases are handled through slab caches due to the
multi-level configurability, only the PTE quicklist remains. As such,
reduce NR_QUICK to its appropriate size and bump down the PTE quicklist
index.
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
The injector filter requires stable_page_flags() which is supplied
by procfs. So make it dependent on that.
Also add ifdefs around the filter code in memory-failure.c so that
when the filter is disabled due to missing dependencies the whole
code still builds.
Reported-by: Ingo Molnar
Signed-off-by: Andi Kleen <ak@linux.intel.com>
In NOMMU mode clamp dac_mmap_min_addr to zero to cause the tests on it to be
skipped by the compiler. We do this as the minimum mmap address doesn't make
any sense in NOMMU mode.
mmap_min_addr and round_hint_to_min() can be discarded entirely in NOMMU mode.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Eric Paris <eparis@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
When specified, only poison pages if ((page_flags & mask) == value).
- corrupt-filter-flags-mask
- corrupt-filter-flags-value
This allows stress testing of many kinds of pages.
Strictly speaking, the buddy pages requires taking zone lock, to avoid
setting PG_hwpoison on a "was buddy but now allocated to someone" page.
However we can just do nothing because we set PG_locked in the beginning,
this prevents the page allocator from allocating it to someone. (It will
BUG() on the unexpected PG_locked, which is fine for hwpoison testing.)
[AK: Add select PROC_PAGE_MONITOR to satisfy dependency]
CC: Nick Piggin <npiggin@suse.de>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Now that ksm pages are swappable, and the known holes plugged, remove
mention of unswappable kernel pages from KSM documentation and comments.
Remove the totalram_pages/4 initialization of max_kernel_pages. In fact,
remove max_kernel_pages altogether - we can reinstate it if removal turns
out to break someone's script; but if we later want to limit KSM's memory
usage, limiting the stable nodes would not be an effective approach.
Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: Izik Eidus <ieidus@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Chris Wright <chrisw@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
CONFIG_DEBUG_SPINLOCK adds 12 or 16 bytes to a 32- or 64-bit spinlock_t,
and CONFIG_DEBUG_LOCK_ALLOC adds another 12 or 24 bytes to it: lockdep
enables both of those, and CONFIG_LOCK_STAT adds 8 or 16 bytes to that.
When 2.6.15 placed the split page table lock inside struct page (usually
sized 32 or 56 bytes), only CONFIG_DEBUG_SPINLOCK was a possibility, and
we ignored the enlargement (but fitted in CONFIG_GENERIC_LOCKBREAK's 4 by
letting the spinlock_t occupy both page->private and page->mapping).
Should these debugging options be allowed to double the size of a struct
page, when only one minority use of the page (as a page table) needs to
fit a spinlock in there? Perhaps not.
Take the easy way out: switch off SPLIT_PTLOCK_CPUS when DEBUG_SPINLOCK or
DEBUG_LOCK_ALLOC is in force. I've sometimes tried to be cleverer,
kmallocing a cacheline for the spinlock when it doesn't fit, but given up
each time. Falling back to mm->page_table_lock (as we do when ptlock is
not split) lets lockdep check out the strictest path anyway.
And now that some arches allow 8192 cpus, use 999999 for infinity.
(What has this got to do with KSM swapping? It doesn't care about the
size of struct page, but may care about random junk in page->mapping - to
be explained separately later.)
Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: Izik Eidus <ieidus@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Nick Piggin <npiggin@suse.de>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Remove three degrees of obfuscation, left over from when we had
CONFIG_UNEVICTABLE_LRU. MLOCK_PAGES is CONFIG_HAVE_MLOCKED_PAGE_BIT is
CONFIG_HAVE_MLOCK is CONFIG_MMU. rmap.o (and memory-failure.o) are only
built when CONFIG_MMU, so don't need such conditions at all.
Somehow, I feel no compulsion to remove the CONFIG_HAVE_MLOCK* lines from
169 defconfigs: leave those to evolve in due course.
Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: Izik Eidus <ieidus@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Nick Piggin <npiggin@suse.de>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Allow memory hotplug and hibernation in the same kernel
Memory hotplug and hibernation were exclusive in Kconfig. This is
obviously a problem for distribution kernels who want to support both in
the same image.
After some discussions with Rafael and others the only problem is with
parallel memory hotadd or removal while a hibernation operation is in
process. It was also working for s390 before.
This patch removes the Kconfig level exclusion, and simply makes the
memory add / remove functions grab the pm_mutex to exclude against
hibernation.
Fixes a regression - old kernels didn't exclude memory hotadd and
hibernation.
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Cc: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Yasunori Goto <y-goto@jp.fujitsu.com>
Acked-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc:
powerpc/ppc64: Use preempt_schedule_irq instead of preempt_schedule
powerpc: Minor cleanup to lib/Kconfig.debug
powerpc: Minor cleanup to sound/ppc/Kconfig
powerpc: Minor cleanup to init/Kconfig
powerpc: Limit memory hotplug support to PPC64 Book-3S machines
powerpc: Limit hugetlbfs support to PPC64 Book-3S machines
powerpc: Fix compile errors found by new ppc64e_defconfig
powerpc: Add a Book-3E 64-bit defconfig
powerpc/booke: Fix xmon single step on PowerPC Book-E
powerpc: Align vDSO base address
powerpc: Fix segment mapping in vdso32
powerpc/iseries: Remove compiler version dependent hack
powerpc/perf_events: Fix priority of MSR HV vs PR bits
powerpc/5200: Update defconfigs
drivers/serial/mpc52xx_uart.c: Use UPIO_MEM rather than SERIAL_IO_MEM
powerpc/boot/dts: drop obsolete 'fsl5200-clocking'
of: Remove nested function
mpc5200: support for the MAN mpc5200 based board mucmc52
mpc5200: support for the MAN mpc5200 based board uc101
Currently, sparsemem is only available if EXPERIMENTAL is enabled.
However, it hasn't ever been marked experimental.
It's been about four years since sparsemem was merged, and we have
platforms which depend on it; allow architectures to decide whether
sparsemem should be the default memory model.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Adjust the max_kernel_pages default to a quarter of totalram_pages,
instead of nr_free_buffer_pages() / 4: the KSM pages themselves come from
highmem, and even on a 16GB PAE machine, 4GB of KSM pages would only be
pinning 32MB of lowmem with their rmap_items, so no need for the more
obscure calculation (nor for its own special init function).
There is no way for the user to switch KSM on if CONFIG_SYSFS is not
enabled, so in that case default run to KSM_RUN_MERGE.
Update KSM Documentation and Kconfig to reflect the new defaults.
Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: Izik Eidus <ieidus@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This build failure triggers:
In file included from include/linux/suspend.h:8,
from arch/x86/kernel/asm-offsets_32.c:11,
from arch/x86/kernel/asm-offsets.c:2:
include/linux/mm.h:503:2: error: #error SECTIONS_WIDTH+NODES_WIDTH+ZONES_WIDTH > BITS_PER_LONG - NR_PAGEFLAGS
Because due to the hwpoison page flag we ran out of page
flags on 32-bit.
Dont turn on hwpoison on 32-bit NUMA (it's rare in any
case).
Also clean up the Kconfig dependencies in the generic MM
code by introducing ARCH_SUPPORTS_MEMORY_FAILURE.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
* 'hwpoison' of git://git.kernel.org/pub/scm/linux/kernel/git/ak/linux-mce-2.6: (21 commits)
HWPOISON: Enable error_remove_page on btrfs
HWPOISON: Add simple debugfs interface to inject hwpoison on arbitary PFNs
HWPOISON: Add madvise() based injector for hardware poisoned pages v4
HWPOISON: Enable error_remove_page for NFS
HWPOISON: Enable .remove_error_page for migration aware file systems
HWPOISON: The high level memory error handler in the VM v7
HWPOISON: Add PR_MCE_KILL prctl to control early kill behaviour per process
HWPOISON: shmem: call set_page_dirty() with locked page
HWPOISON: Define a new error_remove_page address space op for async truncation
HWPOISON: Add invalidate_inode_page
HWPOISON: Refactor truncate to allow direct truncating of page v2
HWPOISON: check and isolate corrupted free pages v2
HWPOISON: Handle hardware poisoned pages in try_to_unmap
HWPOISON: Use bitmask/action code for try_to_unmap behaviour
HWPOISON: x86: Add VM_FAULT_HWPOISON handling to x86 page fault handler v2
HWPOISON: Add poison check to page fault handling
HWPOISON: Add basic support for poisoned pages in fault handler v3
HWPOISON: Add new SIGBUS error codes for hardware poison signals
HWPOISON: Add support for poison swap entries v2
HWPOISON: Export some rmap vma locking to outside world
...
Add Documentation/vm/ksm.txt: how to use the Kernel Samepage Merging feature
Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: Michael Kerrisk <mtk.manpages@googlemail.com>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
Acked-by: Izik Eidus <ieidus@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch presents the mm interface to a dummy version of ksm.c, for
better scrutiny of that interface: the real ksm.c follows later.
When CONFIG_KSM is not set, madvise(2) reject MADV_MERGEABLE and
MADV_UNMERGEABLE with EINVAL, since that seems more helpful than
pretending that they can be serviced. But when CONFIG_KSM=y, accept them
even if KSM is not currently running, and even on areas which KSM will not
touch (e.g. hugetlb or shared file or special driver mappings).
Like other madvices, report ENOMEM despite success if any area in the
range is unmapped, and use EAGAIN to report out of memory.
Define vma flag VM_MERGEABLE to identify an area on which KSM may try
merging pages: leave it to ksm_madvise() to decide whether to set it.
Define mm flag MMF_VM_MERGEABLE to identify an mm which might contain
VM_MERGEABLE areas, to minimize callouts when forking or exiting.
Based upon earlier patches by Chris Wright and Izik Eidus.
Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Signed-off-by: Chris Wright <chrisw@redhat.com>
Signed-off-by: Izik Eidus <ieidus@redhat.com>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Avi Kivity <avi@redhat.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Useful for some testing scenarios, although specific testing is often
done better through MADV_POISON
This can be done with the x86 level MCE injector too, but this interface
allows it to do independently from low level x86 changes.
v2: Add module license (Haicheng Li)
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Add the high level memory handler that poisons pages
that got corrupted by hardware (typically by a two bit flip in a DIMM
or a cache) on the Linux level. The goal is to prevent everyone
from accessing these pages in the future.
This done at the VM level by marking a page hwpoisoned
and doing the appropriate action based on the type of page
it is.
The code that does this is portable and lives in mm/memory-failure.c
To quote the overview comment:
High level machine check handler. Handles pages reported by the
hardware as being corrupted usually due to a 2bit ECC memory or cache
failure.
This focuses on pages detected as corrupted in the background.
When the current CPU tries to consume corruption the currently
running process can just be killed directly instead. This implies
that if the error cannot be handled for some reason it's safe to
just ignore it because no corruption has been consumed yet. Instead
when that happens another machine check will happen.
Handles page cache pages in various states. The tricky part
here is that we can access any page asynchronous to other VM
users, because memory failures could happen anytime and anywhere,
possibly violating some of their assumptions. This is why this code
has to be extremely careful. Generally it tries to use normal locking
rules, as in get the standard locks, even if that means the
error handling takes potentially a long time.
Some of the operations here are somewhat inefficient and have non
linear algorithmic complexity, because the data structures have not
been optimized for this case. This is in particular the case
for the mapping from a vma to a process. Since this case is expected
to be rare we hope we can get away with this.
There are in principle two strategies to kill processes on poison:
- just unmap the data and wait for an actual reference before
killing
- kill as soon as corruption is detected.
Both have advantages and disadvantages and should be used
in different situations. Right now both are implemented and can
be switched with a new sysctl vm.memory_failure_early_kill
The default is early kill.
The patch does some rmap data structure walking on its own to collect
processes to kill. This is unusual because normally all rmap data structure
knowledge is in rmap.c only. I put it here for now to keep
everything together and rmap knowledge has been seeping out anyways
Includes contributions from Johannes Weiner, Chris Mason, Fengguang Wu,
Nick Piggin (who did a lot of great work) and others.
Cc: npiggin@suse.de
Cc: riel@redhat.com
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Rik van Riel <riel@redhat.com>
Reviewed-by: Hidehiro Kawai <hidehiro.kawai.ez@hitachi.com>
* 'x86-pat-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
x86, pat: Fix cacheflush address in change_page_attr_set_clr()
mm: remove !NUMA condition from PAGEFLAGS_EXTENDED condition set
x86: Fix earlyprintk=dbgp for machines without NX
x86, pat: Sanity check remap_pfn_range for RAM region
x86, pat: Lookup the protection from memtype list on vm_insert_pfn()
x86, pat: Add lookup_memtype to get the current memtype of a paddr
x86, pat: Use page flags to track memtypes of RAM pages
x86, pat: Generalize the use of page flag PG_uncached
x86, pat: Add rbtree to do quick lookup in memtype tracking
x86, pat: Add PAT reserve free to io_mapping* APIs
x86, pat: New i/f for driver to request memtype for IO regions
x86, pat: ioremap to follow same PAT restrictions as other PAT users
x86, pat: Keep identity maps consistent with mmaps even when pat_disabled
x86, mtrr: make mtrr_aps_delayed_init static bool
x86, pat/mtrr: Rendezvous all the cpus for MTRR/PAT init
generic-ipi: Allow cpus not yet online to call smp_call_function with irqs disabled
x86: Fix an incorrect argument of reserve_bootmem()
x86: Fix system crash when loading with "reservetop" parameter
