| Commit message (Collapse) | Author | Age | Files | Lines |
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GCC version 5.4.1+svn241155-1 in Debian Stretch has a bug that breaks
the build. The error is attached.
TODO: Gigure out the actual bug or revert patch if a newer GCC is
available in Stretch.
/home/wolfi/6.0-romsrc/kernel/samsung/smdk4412/mm/vmscan.c: In function 'shrink_page_list':
/home/wolfi/6.0-romsrc/kernel/samsung/smdk4412/mm/vmscan.c:1019:1: error: insn does not satisfy its constraints:
}
^
(insn 1111 1814 1112 116 (parallel [
(set (reg/v:SI 3 r3 [orig:111 nr_dirty ] [111])
(and:SI (ne:SI (reg/v:SI 3 r3 [orig:111 nr_dirty ] [111])
(const_int 0 [0]))
(eq:SI (reg/v:SI 3 r3 [orig:111 nr_dirty ] [111])
(reg/v:SI 2 r2 [orig:112 nr_congested ] [112]))))
(clobber (reg:CC 100 cc))
]) /home/wolfi/6.0-romsrc/kernel/samsung/smdk4412/mm/vmscan.c:1011 256 {*and_scc_scc_nodom}
(nil))
/home/wolfi/6.0-romsrc/kernel/samsung/smdk4412/mm/vmscan.c:1019:1: internal compiler error: in extract_constrain_insn, at recog.c:2246
/home/wolfi/6.0-romsrc/kernel/samsung/smdk4412/mm/vmscan.c:1019:1: internal compiler error: Segmentation fault
arm-none-eabi-gcc: internal compiler error: Segmentation fault (program cc1)
Signed-off-by: Wolfgang Wiedmeyer <wolfgit@wiedmeyer.de>
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This is an ancient bug that was actually attempted to be fixed once
(badly) by me eleven years ago in commit 4ceb5db9757a ("Fix
get_user_pages() race for write access") but that was then undone due to
problems on s390 by commit f33ea7f404e5 ("fix get_user_pages bug").
In the meantime, the s390 situation has long been fixed, and we can now
fix it by checking the pte_dirty() bit properly (and do it better). The
s390 dirty bit was implemented in abf09bed3cce ("s390/mm: implement
software dirty bits") which made it into v3.9. Earlier kernels will
have to look at the page state itself.
Also, the VM has become more scalable, and what used a purely
theoretical race back then has become easier to trigger.
To fix it, we introduce a new internal FOLL_COW flag to mark the "yes,
we already did a COW" rather than play racy games with FOLL_WRITE that
is very fundamental, and then use the pte dirty flag to validate that
the FOLL_COW flag is still valid.
Change-Id: Id9bec3722797dff7d0ff0d9f6097c4229e31fd62
Reported-and-tested-by: Phil "not Paul" Oester <kernel@linuxace.com>
Acked-by: Hugh Dickins <hughd@google.com>
Reviewed-by: Michal Hocko <mhocko@suse.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Willy Tarreau <w@1wt.eu>
Cc: Nick Piggin <npiggin@gmail.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[wt: s/gup.c/memory.c; s/follow_page_pte/follow_page_mask;
s/faultin_page/__get_user_page]
Signed-off-by: Willy Tarreau <w@1wt.eu>
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also fix a merge error @ putback_lru_page
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(Feedback welcome if there is a different/better way to do this
without using a page flag!)
Since about 2.6.27, the page replacement algorithm maintains
an "active" bit to help decide which pages are most eligible
to reclaim, see http://linux-mm.org/PageReplacementDesign
This "active' information is also useful to cleancache but is lost
by the time that cleancache has the opportunity to preserve the
pageful of data. This patch adds a new page flag "WasActive" to
retain the state. The flag may possibly be useful elsewhere.
It is up to each cleancache backend to utilize the bit as
it desires. The matching patch for zcache is included here
for clarification/discussion purposes, though it will need to
go through GregKH and the staging tree.
The patch resolves issues reported with cleancache which occur
especially during streaming workloads on older processors,
see https://lkml.org/lkml/2011/8/17/351
Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com>
Conflicts:
include/linux/page-flags.h
Change-Id: I0fcb2302a7b9c5e66db005229f679baee90f262f
Conflicts:
include/linux/page-flags.h
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Swap subsystem does lazy swap slot free with expecting the page would be
swapped out again so we can avoid unnecessary write.
But the problem in in-memory swap(ex, zram) is that it consumes memory
space until vm_swap_full(ie, used half of all of swap device) condition
meet. It could be bad if we use multiple swap device, small in-memory
swap and big storage swap or in-memory swap alone.
This patch makes swap subsystem free swap slot as soon as swap-read is
completed and make the swapcache page dirty so the page should be
written out the swap device to reclaim it. It means we never lose it.
I tested this patch with kernel compile workload.
1. before
compile time : 9882.42
zram max wasted space by fragmentation: 13471881 byte
memory space consumed by zram: 174227456 byte
the number of slot free notify: 206684
2. after
compile time : 9653.90
zram max wasted space by fragmentation: 11805932 byte
memory space consumed by zram: 154001408 byte
the number of slot free notify: 426972
[akpm@linux-foundation.org: tweak comment text]
[artem.savkov@gmail.com: fix BUG due to non-swapcache pages in end_swap_bio_read()]
[akpm@linux-foundation.org: invert unlikely() test, augment comment, 80-col cleanup]
Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com>
Signed-off-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Artem Savkov <artem.savkov@gmail.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Seth Jennings <sjenning@linux.vnet.ibm.com>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Konrad Rzeszutek Wilk <konrad@darnok.org>
Cc: Shaohua Li <shli@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Change-Id: I8f11fb7f0391954435002e7f290352f311c907d4
Signed-off-by: Paul Reioux <reioux@gmail.com>
Conflicts:
mm/page_io.c
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Stolen from commit f981c5950fa85916ba49bea5d9a7a5078f47e569:
"mm: methods for teaching filesystems about PG_swapcache pages"
Change-Id: I6673913f9c825d3a6de88a652e99bcaf04eb1dd6
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There are couple of issues with swapcache usage when ZRAM is used
as swap device.
1) Kernel does a swap readahead which can be around 6 to 8 pages
depending on total ram, which is not required for zram since
accesses are fast.
2) Kernel delays the freeing up of swapcache expecting a later hit,
which again is useless in the case of zram.
3) This is not related to swapcache, but zram usage itself.
As mentioned in (2) kernel delays freeing of swapcache, but along with
that it delays zram compressed page free also. i.e. there can be 2 copies,
though one is compressed.
This patch addresses these issues using two new flags
QUEUE_FLAG_FAST and SWP_FAST, to indicate that accesses to the device
will be fast and cheap, and instructs the swap layer to free up
swap space agressively, and not to do read ahead.
Change-Id: I5d2d5176a5f9420300bb2f843f6ecbdb25ea80e4
Signed-off-by: Vinayak Menon <vinmenon@codeaurora.org>
Signed-off-by: D. Andrei Măceș <dmaces@nd.edu>
Conflicts:
include/linux/blkdev.h
include/linux/swap.h
mm/swap_state.c
mm/swapfile.c
Conflicts:
include/linux/blkdev.h
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In zs_create_pool(), we allocate memory more then sizeof(struct zs_pool)
ovhd_size = roundup(sizeof(*pool), PAGE_SIZE);
This patch allocate memory of exactly needed size.
Change-Id: Id0ada356009c92bf791c94be073f4467f7bb1aac
Signed-off-by: Ganesh Mahendran <opensource.ganesh@gmail.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Dan Streetman <ddstreet@ieee.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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The kunmap_atomic should use virtual address getting by kmap_atomic.
However, some pieces of code in zsmalloc uses modified address, not the
one got by kmap_atomic for kunmap_atomic.
It's okay for working because zsmalloc modifies the address inner
PAGE_SIZE bounday so it works with current kmap_atomic's implementation.
But it's still fragile with potential changing of kmap_atomic so let's
correct it.
I got a subtle bug when I implemented a new feature of zsmalloc
(compaction) due to a link's mishandling (the link was over page
boundary). Although it was totally my mistake, it took a while to find
the cause because an unpredictable kmapped address was unmapped causing an
almost random crash.
Change-Id: Ic637e7d65e743a42df5833566054634c9a08f86d
Signed-off-by: Minchan Kim <minchan@kernel.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Dan Streetman <ddstreet@ieee.org>
Cc: Seth Jennings <sjennings@variantweb.net>
Cc: Jerome Marchand <jmarchan@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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zsmalloc has many size_classes to reduce fragmentation and they are in 16
bytes unit, for example, 16, 32, 48, etc., if PAGE_SIZE is 4096. And,
zsmalloc has constraint that each zspage has 4 pages at maximum.
In this situation, we can see interesting aspect. Let's think about
size_class for 1488, 1472, ..., 1376. To prevent external fragmentation,
they uses 4 pages per zspage and so all they can contain 11 objects at
maximum.
16384 (4096 * 4) = 1488 * 11 + remains
16384 (4096 * 4) = 1472 * 11 + remains
16384 (4096 * 4) = ...
16384 (4096 * 4) = 1376 * 11 + remains
It means that they have same characteristics and classification between
them isn't needed. If we use one size_class for them, we can reduce
fragementation and save some memory since both the 1488 and 1472 sized
classes can only fit 11 objects into 4 pages, and an object that's 1472
bytes can fit into an object that's 1488 bytes, merging these classes to
always use objects that are 1488 bytes will reduce the total number of
size classes. And reducing the total number of size classes reduces
overall fragmentation, because a wider range of compressed pages can fit
into a single size class, leaving less unused objects in each size class.
For this purpose, this patch implement size_class merging. If there is
size_class that have same pages_per_zspage and same number of objects per
zspage with previous size_class, we don't create new size_class. Instead,
we use previous, same characteristic size_class. With this way, above
example sizes (1488, 1472, ..., 1376) use just one size_class so we can
get much more memory utilization.
Below is result of my simple test.
TEST ENV: EXT4 on zram, mount with discard option WORKLOAD: untar kernel
source code, remove directory in descending order in size. (drivers arch
fs sound include net Documentation firmware kernel tools)
Each line represents orig_data_size, compr_data_size, mem_used_total,
fragmentation overhead (mem_used - compr_data_size) and overhead ratio
(overhead to compr_data_size), respectively, after untar and remove
operation is executed.
* untar-nomerge.out
orig_size compr_size used_size overhead overhead_ratio
525.88MB 199.16MB 210.23MB 11.08MB 5.56%
288.32MB 97.43MB 105.63MB 8.20MB 8.41%
177.32MB 61.12MB 69.40MB 8.28MB 13.55%
146.47MB 47.32MB 56.10MB 8.78MB 18.55%
124.16MB 38.85MB 48.41MB 9.55MB 24.58%
103.93MB 31.68MB 40.93MB 9.25MB 29.21%
84.34MB 22.86MB 32.72MB 9.86MB 43.13%
66.87MB 14.83MB 23.83MB 9.00MB 60.70%
60.67MB 11.11MB 18.60MB 7.49MB 67.48%
55.86MB 8.83MB 16.61MB 7.77MB 88.03%
53.32MB 8.01MB 15.32MB 7.31MB 91.24%
* untar-merge.out
orig_size compr_size used_size overhead overhead_ratio
526.23MB 199.18MB 209.81MB 10.64MB 5.34%
288.68MB 97.45MB 104.08MB 6.63MB 6.80%
177.68MB 61.14MB 66.93MB 5.79MB 9.47%
146.83MB 47.34MB 52.79MB 5.45MB 11.51%
124.52MB 38.87MB 44.30MB 5.43MB 13.96%
104.29MB 31.70MB 36.83MB 5.13MB 16.19%
84.70MB 22.88MB 27.92MB 5.04MB 22.04%
67.11MB 14.83MB 19.26MB 4.43MB 29.86%
60.82MB 11.10MB 14.90MB 3.79MB 34.17%
55.90MB 8.82MB 12.61MB 3.79MB 42.97%
53.32MB 8.01MB 11.73MB 3.73MB 46.53%
As you can see above result, merged one has better utilization (overhead
ratio, 5th column) and uses less memory (mem_used_total, 3rd column).
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Jerome Marchand <jmarchan@redhat.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Reviewed-by: Dan Streetman <ddstreet@ieee.org>
Cc: Luigi Semenzato <semenzato@google.com>
Cc: <juno.choi@lge.com>
Cc: "seungho1.park" <seungho1.park@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Change zsmalloc init_zspage() logic to iterate through each object on each
of its pages, checking the offset to verify the object is on the current
page before linking it into the zspage.
The current zsmalloc init_zspage free object linking code has logic that
relies on there only being one page per zspage when PAGE_SIZE is a
multiple of class->size. It calculates the number of objects for the
current page, and iterates through all of them plus one, to account for
the assumed partial object at the end of the page. While this currently
works, the logic can be simplified to just link the object at each
successive offset until the offset is larger than PAGE_SIZE, which does
not rely on PAGE_SIZE being a multiple of class->size.
Signed-off-by: Dan Streetman <ddstreet@ieee.org>
Acked-by: Minchan Kim <minchan@kernel.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Seth Jennings <sjennings@variantweb.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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zs_get_total_size_bytes returns a amount of memory zsmalloc consumed with
*byte unit* but zsmalloc operates *page unit* rather than byte unit so
let's change the API so benefit we could get is that reduce unnecessary
overhead (ie, change page unit with byte unit) in zsmalloc.
Since return type is pages, "zs_get_total_pages" is better than
"zs_get_total_size_bytes".
Signed-off-by: Minchan Kim <minchan@kernel.org>
Reviewed-by: Dan Streetman <ddstreet@ieee.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Jerome Marchand <jmarchan@redhat.com>
Cc: <juno.choi@lge.com>
Cc: <seungho1.park@lge.com>
Cc: Luigi Semenzato <semenzato@google.com>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Seth Jennings <sjennings@variantweb.net>
Cc: David Horner <ds2horner@gmail.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Conflicts:
mm/zsmalloc.c
Change-Id: If5697d7b7f8ebaab3b58c1f9f84de747eb909ca3
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Currently, zram has no feature to limit memory so theoretically zram can
deplete system memory. Users have asked for a limit several times as even
without exhaustion zram makes it hard to control memory usage of the
platform. This patchset adds the feature.
Patch 1 makes zs_get_total_size_bytes faster because it would be used
frequently in later patches for the new feature.
Patch 2 changes zs_get_total_size_bytes's return unit from bytes to page
so that zsmalloc doesn't need unnecessary operation(ie, << PAGE_SHIFT).
Patch 3 adds new feature. I added the feature into zram layer, not
zsmalloc because limiation is zram's requirement, not zsmalloc so any
other user using zsmalloc(ie, zpool) shouldn't affected by unnecessary
branch of zsmalloc. In future, if every users of zsmalloc want the
feature, then, we could move the feature from client side to zsmalloc
easily but vice versa would be painful.
Patch 4 adds news facility to report maximum memory usage of zram so that
this avoids user polling frequently via /sys/block/zram0/ mem_used_total
and ensures transient max are not missed.
This patch (of 4):
pages_allocated has counted in size_class structure and when user of
zsmalloc want to see total_size_bytes, it should gather all of count from
each size_class to report the sum.
It's not bad if user don't see the value often but if user start to see
the value frequently, it would be not a good deal for performance pov.
This patch moves the count from size_class to zs_pool so it could reduce
memory footprint (from [255 * 8byte] to [sizeof(atomic_long_t)]).
Signed-off-by: Minchan Kim <minchan@kernel.org>
Reviewed-by: Dan Streetman <ddstreet@ieee.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Jerome Marchand <jmarchan@redhat.com>
Cc: <juno.choi@lge.com>
Cc: <seungho1.park@lge.com>
Cc: Luigi Semenzato <semenzato@google.com>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Seth Jennings <sjennings@variantweb.net>
Reviewed-by: David Horner <ds2horner@gmail.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Add my copyright to the zsmalloc source code which I maintain.
Signed-off-by: Minchan Kim <minchan@kernel.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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This patch moves zsmalloc under mm directory.
Before that, description will explain why we have needed custom
allocator.
Zsmalloc is a new slab-based memory allocator for storing compressed
pages. It is designed for low fragmentation and high allocation success
rate on large object, but <= PAGE_SIZE allocations.
zsmalloc differs from the kernel slab allocator in two primary ways to
achieve these design goals.
zsmalloc never requires high order page allocations to back slabs, or
"size classes" in zsmalloc terms. Instead it allows multiple
single-order pages to be stitched together into a "zspage" which backs
the slab. This allows for higher allocation success rate under memory
pressure.
Also, zsmalloc allows objects to span page boundaries within the zspage.
This allows for lower fragmentation than could be had with the kernel
slab allocator for objects between PAGE_SIZE/2 and PAGE_SIZE. With the
kernel slab allocator, if a page compresses to 60% of it original size,
the memory savings gained through compression is lost in fragmentation
because another object of the same size can't be stored in the leftover
space.
This ability to span pages results in zsmalloc allocations not being
directly addressable by the user. The user is given an
non-dereferencable handle in response to an allocation request. That
handle must be mapped, using zs_map_object(), which returns a pointer to
the mapped region that can be used. The mapping is necessary since the
object data may reside in two different noncontigious pages.
The zsmalloc fulfills the allocation needs for zram perfectly
[sjenning@linux.vnet.ibm.com: borrow Seth's quote]
Signed-off-by: Minchan Kim <minchan@kernel.org>
Acked-by: Nitin Gupta <ngupta@vflare.org>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Bob Liu <bob.liu@oracle.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Luigi Semenzato <semenzato@google.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Seth Jennings <sjenning@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Change-Id: Ib026c17143131089494dc394c4a35e230220ec83
Conflicts:
drivers/staging/Kconfig
drivers/staging/Makefile
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Complete the renaming from "flush" to "invalidate" across
both tmem frontends (cleancache and frontswap) and both tmem backends
(Xen and zcache), as required by akpm.
This change is completely cosmetic.
[v10: no change]
[v9: akpm@linux-foundation.org: change "flush" to "invalidate", part 3]
Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com>
Cc: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: 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>
[v11: Remove the frontswap part]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Conflicts:
drivers/xen/tmem.c
include/linux/cleancache.h
Change-Id: Id9661e5fc4bb6f416129f38c1e3df80319653041
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Btrfs has to make sure we have space to allocate new blocks in order to modify
the inode, so updating time can fail. We've gotten around this by having our
own file_update_time but this is kind of a pain, and Christoph has indicated he
would like to make xfs do something different with atime updates. So introduce
->update_time, where we will deal with i_version an a/m/c time updates and
indicate which changes need to be made. The normal version just does what it
has always done, updates the time and marks the inode dirty, and then
filesystems can choose to do something different.
I've gone through all of the users of file_update_time and made them check for
errors with the exception of the fault code since it's complicated and I wasn't
quite sure what to do there, also Jan is going to be pushing the file time
updates into page_mkwrite for those who have it so that should satisfy btrfs and
make it not a big deal to check the file_update_time() return code in the
generic fault path. Thanks,
Signed-off-by: Josef Bacik <josef@redhat.com>
(cherry picked from commit c3b2da314834499f34cba94f7053e55f6d6f92d8)
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Userspace processes often have multiple allocators that each do
anonymous mmaps to get memory. When examining memory usage of
individual processes or systems as a whole, it is useful to be
able to break down the various heaps that were allocated by
each layer and examine their size, RSS, and physical memory
usage.
This patch adds a user pointer to the shared union in
vm_area_struct that points to a null terminated string inside
the user process containing a name for the vma. vmas that
point to the same address will be merged, but vmas that
point to equivalent strings at different addresses will
not be merged.
Userspace can set the name for a region of memory by calling
prctl(PR_SET_VMA, PR_SET_VMA_ANON_NAME, start, len, (unsigned long)name);
Setting the name to NULL clears it.
The names of named anonymous vmas are shown in /proc/pid/maps
as [anon:<name>] and in /proc/pid/smaps in a new "Name" field
that is only present for named vmas. If the userspace pointer
is no longer valid all or part of the name will be replaced
with "<fault>".
The idea to store a userspace pointer to reduce the complexity
within mm (at the expense of the complexity of reading
/proc/pid/mem) came from Dave Hansen. This results in no
runtime overhead in the mm subsystem other than comparing
the anon_name pointers when considering vma merging. The pointer
is stored in a union with fieds that are only used on file-backed
mappings, so it does not increase memory usage.
Conflicts:
include/linux/prctl.h
kernel/sys.c
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Stack for a new thread is mapped by userspace code and passed via
sys_clone. This memory is currently seen as anonymous in
/proc/<pid>/maps, which makes it difficult to ascertain which mappings
are being used for thread stacks. This patch uses the individual task
stack pointers to determine which vmas are actually thread stacks.
For a multithreaded program like the following:
#include <pthread.h>
void *thread_main(void *foo)
{
while(1);
}
int main()
{
pthread_t t;
pthread_create(&t, NULL, thread_main, NULL);
pthread_join(t, NULL);
}
proc/PID/maps looks like the following:
00400000-00401000 r-xp 00000000 fd:0a 3671804 /home/siddhesh/a.out
00600000-00601000 rw-p 00000000 fd:0a 3671804 /home/siddhesh/a.out
019ef000-01a10000 rw-p 00000000 00:00 0 [heap]
7f8a44491000-7f8a44492000 ---p 00000000 00:00 0
7f8a44492000-7f8a44c92000 rw-p 00000000 00:00 0
7f8a44c92000-7f8a44e3d000 r-xp 00000000 fd:00 2097482 /lib64/libc-2.14.90.so
7f8a44e3d000-7f8a4503d000 ---p 001ab000 fd:00 2097482 /lib64/libc-2.14.90.so
7f8a4503d000-7f8a45041000 r--p 001ab000 fd:00 2097482 /lib64/libc-2.14.90.so
7f8a45041000-7f8a45043000 rw-p 001af000 fd:00 2097482 /lib64/libc-2.14.90.so
7f8a45043000-7f8a45048000 rw-p 00000000 00:00 0
7f8a45048000-7f8a4505f000 r-xp 00000000 fd:00 2099938 /lib64/libpthread-2.14.90.so
7f8a4505f000-7f8a4525e000 ---p 00017000 fd:00 2099938 /lib64/libpthread-2.14.90.so
7f8a4525e000-7f8a4525f000 r--p 00016000 fd:00 2099938 /lib64/libpthread-2.14.90.so
7f8a4525f000-7f8a45260000 rw-p 00017000 fd:00 2099938 /lib64/libpthread-2.14.90.so
7f8a45260000-7f8a45264000 rw-p 00000000 00:00 0
7f8a45264000-7f8a45286000 r-xp 00000000 fd:00 2097348 /lib64/ld-2.14.90.so
7f8a45457000-7f8a4545a000 rw-p 00000000 00:00 0
7f8a45484000-7f8a45485000 rw-p 00000000 00:00 0
7f8a45485000-7f8a45486000 r--p 00021000 fd:00 2097348 /lib64/ld-2.14.90.so
7f8a45486000-7f8a45487000 rw-p 00022000 fd:00 2097348 /lib64/ld-2.14.90.so
7f8a45487000-7f8a45488000 rw-p 00000000 00:00 0
7fff6273b000-7fff6275c000 rw-p 00000000 00:00 0 [stack]
7fff627ff000-7fff62800000 r-xp 00000000 00:00 0 [vdso]
ffffffffff600000-ffffffffff601000 r-xp 00000000 00:00 0 [vsyscall]
Here, one could guess that 7f8a44492000-7f8a44c92000 is a stack since
the earlier vma that has no permissions (7f8a44e3d000-7f8a4503d000) but
that is not always a reliable way to find out which vma is a thread
stack. Also, /proc/PID/maps and /proc/PID/task/TID/maps has the same
content.
With this patch in place, /proc/PID/task/TID/maps are treated as 'maps
as the task would see it' and hence, only the vma that that task uses as
stack is marked as [stack]. All other 'stack' vmas are marked as
anonymous memory. /proc/PID/maps acts as a thread group level view,
where all thread stack vmas are marked as [stack:TID] where TID is the
process ID of the task that uses that vma as stack, while the process
stack is marked as [stack].
So /proc/PID/maps will look like this:
00400000-00401000 r-xp 00000000 fd:0a 3671804 /home/siddhesh/a.out
00600000-00601000 rw-p 00000000 fd:0a 3671804 /home/siddhesh/a.out
019ef000-01a10000 rw-p 00000000 00:00 0 [heap]
7f8a44491000-7f8a44492000 ---p 00000000 00:00 0
7f8a44492000-7f8a44c92000 rw-p 00000000 00:00 0 [stack:1442]
7f8a44c92000-7f8a44e3d000 r-xp 00000000 fd:00 2097482 /lib64/libc-2.14.90.so
7f8a44e3d000-7f8a4503d000 ---p 001ab000 fd:00 2097482 /lib64/libc-2.14.90.so
7f8a4503d000-7f8a45041000 r--p 001ab000 fd:00 2097482 /lib64/libc-2.14.90.so
7f8a45041000-7f8a45043000 rw-p 001af000 fd:00 2097482 /lib64/libc-2.14.90.so
7f8a45043000-7f8a45048000 rw-p 00000000 00:00 0
7f8a45048000-7f8a4505f000 r-xp 00000000 fd:00 2099938 /lib64/libpthread-2.14.90.so
7f8a4505f000-7f8a4525e000 ---p 00017000 fd:00 2099938 /lib64/libpthread-2.14.90.so
7f8a4525e000-7f8a4525f000 r--p 00016000 fd:00 2099938 /lib64/libpthread-2.14.90.so
7f8a4525f000-7f8a45260000 rw-p 00017000 fd:00 2099938 /lib64/libpthread-2.14.90.so
7f8a45260000-7f8a45264000 rw-p 00000000 00:00 0
7f8a45264000-7f8a45286000 r-xp 00000000 fd:00 2097348 /lib64/ld-2.14.90.so
7f8a45457000-7f8a4545a000 rw-p 00000000 00:00 0
7f8a45484000-7f8a45485000 rw-p 00000000 00:00 0
7f8a45485000-7f8a45486000 r--p 00021000 fd:00 2097348 /lib64/ld-2.14.90.so
7f8a45486000-7f8a45487000 rw-p 00022000 fd:00 2097348 /lib64/ld-2.14.90.so
7f8a45487000-7f8a45488000 rw-p 00000000 00:00 0
7fff6273b000-7fff6275c000 rw-p 00000000 00:00 0 [stack]
7fff627ff000-7fff62800000 r-xp 00000000 00:00 0 [vdso]
ffffffffff600000-ffffffffff601000 r-xp 00000000 00:00 0 [vsyscall]
Thus marking all vmas that are used as stacks by the threads in the
thread group along with the process stack. The task level maps will
however like this:
00400000-00401000 r-xp 00000000 fd:0a 3671804 /home/siddhesh/a.out
00600000-00601000 rw-p 00000000 fd:0a 3671804 /home/siddhesh/a.out
019ef000-01a10000 rw-p 00000000 00:00 0 [heap]
7f8a44491000-7f8a44492000 ---p 00000000 00:00 0
7f8a44492000-7f8a44c92000 rw-p 00000000 00:00 0 [stack]
7f8a44c92000-7f8a44e3d000 r-xp 00000000 fd:00 2097482 /lib64/libc-2.14.90.so
7f8a44e3d000-7f8a4503d000 ---p 001ab000 fd:00 2097482 /lib64/libc-2.14.90.so
7f8a4503d000-7f8a45041000 r--p 001ab000 fd:00 2097482 /lib64/libc-2.14.90.so
7f8a45041000-7f8a45043000 rw-p 001af000 fd:00 2097482 /lib64/libc-2.14.90.so
7f8a45043000-7f8a45048000 rw-p 00000000 00:00 0
7f8a45048000-7f8a4505f000 r-xp 00000000 fd:00 2099938 /lib64/libpthread-2.14.90.so
7f8a4505f000-7f8a4525e000 ---p 00017000 fd:00 2099938 /lib64/libpthread-2.14.90.so
7f8a4525e000-7f8a4525f000 r--p 00016000 fd:00 2099938 /lib64/libpthread-2.14.90.so
7f8a4525f000-7f8a45260000 rw-p 00017000 fd:00 2099938 /lib64/libpthread-2.14.90.so
7f8a45260000-7f8a45264000 rw-p 00000000 00:00 0
7f8a45264000-7f8a45286000 r-xp 00000000 fd:00 2097348 /lib64/ld-2.14.90.so
7f8a45457000-7f8a4545a000 rw-p 00000000 00:00 0
7f8a45484000-7f8a45485000 rw-p 00000000 00:00 0
7f8a45485000-7f8a45486000 r--p 00021000 fd:00 2097348 /lib64/ld-2.14.90.so
7f8a45486000-7f8a45487000 rw-p 00022000 fd:00 2097348 /lib64/ld-2.14.90.so
7f8a45487000-7f8a45488000 rw-p 00000000 00:00 0
7fff6273b000-7fff6275c000 rw-p 00000000 00:00 0
7fff627ff000-7fff62800000 r-xp 00000000 00:00 0 [vdso]
ffffffffff600000-ffffffffff601000 r-xp 00000000 00:00 0 [vsyscall]
where only the vma that is being used as a stack by *that* task is
marked as [stack].
Analogous changes have been made to /proc/PID/smaps,
/proc/PID/numa_maps, /proc/PID/task/TID/smaps and
/proc/PID/task/TID/numa_maps. Relevant snippets from smaps and
numa_maps:
[siddhesh@localhost ~ ]$ pgrep a.out
1441
[siddhesh@localhost ~ ]$ cat /proc/1441/smaps | grep "\[stack"
7f8a44492000-7f8a44c92000 rw-p 00000000 00:00 0 [stack:1442]
7fff6273b000-7fff6275c000 rw-p 00000000 00:00 0 [stack]
[siddhesh@localhost ~ ]$ cat /proc/1441/task/1442/smaps | grep "\[stack"
7f8a44492000-7f8a44c92000 rw-p 00000000 00:00 0 [stack]
[siddhesh@localhost ~ ]$ cat /proc/1441/task/1441/smaps | grep "\[stack"
7fff6273b000-7fff6275c000 rw-p 00000000 00:00 0 [stack]
[siddhesh@localhost ~ ]$ cat /proc/1441/numa_maps | grep "stack"
7f8a44492000 default stack:1442 anon=2 dirty=2 N0=2
7fff6273a000 default stack anon=3 dirty=3 N0=3
[siddhesh@localhost ~ ]$ cat /proc/1441/task/1442/numa_maps | grep "stack"
7f8a44492000 default stack anon=2 dirty=2 N0=2
[siddhesh@localhost ~ ]$ cat /proc/1441/task/1441/numa_maps | grep "stack"
7fff6273a000 default stack anon=3 dirty=3 N0=3
[akpm@linux-foundation.org: checkpatch fixes]
[akpm@linux-foundation.org: fix build]
Signed-off-by: Siddhesh Poyarekar <siddhesh.poyarekar@gmail.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@gmail.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Jamie Lokier <jamie@shareable.org>
Cc: Mike Frysinger <vapier@gentoo.org>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Matt Mackall <mpm@selenic.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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With this patch userland applications that want to maintain the
interactivity/memory allocation cost can use the pressure level
notifications. The levels are defined like this:
The "low" level means that the system is reclaiming memory for new
allocations. Monitoring this reclaiming activity might be useful for
maintaining cache level. Upon notification, the program (typically
"Activity Manager") might analyze vmstat and act in advance (i.e.
prematurely shutdown unimportant services).
The "medium" level means that the system is experiencing medium memory
pressure, the system might be making swap, paging out active file
caches, etc. Upon this event applications may decide to further analyze
vmstat/zoneinfo/memcg or internal memory usage statistics and free any
resources that can be easily reconstructed or re-read from a disk.
The "critical" level means that the system is actively thrashing, it is
about to out of memory (OOM) or even the in-kernel OOM killer is on its
way to trigger. Applications should do whatever they can to help the
system. It might be too late to consult with vmstat or any other
statistics, so it's advisable to take an immediate action.
The events are propagated upward until the event is handled, i.e. the
events are not pass-through. Here is what this means: for example you
have three cgroups: A->B->C. Now you set up an event listener on
cgroups A, B and C, and suppose group C experiences some pressure. In
this situation, only group C will receive the notification, i.e. groups
A and B will not receive it. This is done to avoid excessive
"broadcasting" of messages, which disturbs the system and which is
especially bad if we are low on memory or thrashing. So, organize the
cgroups wisely, or propagate the events manually (or, ask us to
implement the pass-through events, explaining why would you need them.)
Performance wise, the memory pressure notifications feature itself is
lightweight and does not require much of bookkeeping, in contrast to the
rest of memcg features. Unfortunately, as of current memcg
implementation, pages accounting is an inseparable part and cannot be
turned off. The good news is that there are some efforts[1] to improve
the situation; plus, implementing the same, fully API-compatible[2]
interface for CONFIG_CGROUP_MEM_RES_CTLR=n case (e.g. embedded) is also
a viable option, so it will not require any changes on the userland
side.
[1] http://permalink.gmane.org/gmane.linux.kernel.cgroups/6291
[2] http://lkml.org/lkml/2013/2/21/454
Change-Id: Ib7b9f7986008d423b84152e2781d0402a560c95e
[akpm@linux-foundation.org: coding-style fixes]
[akpm@linux-foundation.org: fix CONFIG_CGROPUPS=n warnings]
Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org>
Acked-by: Kirill A. Shutemov <kirill@shutemov.name>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Glauber Costa <glommer@parallels.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Luiz Capitulino <lcapitulino@redhat.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Leonid Moiseichuk <leonid.moiseichuk@nokia.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@gmail.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Cc: John Stultz <john.stultz@linaro.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Conflicts:
mm/memcontrol.c
mm/vmscan.c
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For shrinkers that have their own cond_resched* calls, having
shrink_slab break the work down into small batches is not
paticularly efficient. Add a custom batchsize field to the struct
shrinker so that shrinkers can use a larger batch size if they
desire.
A value of zero (uninitialised) means "use the default", so
behaviour is unchanged by this patch.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Conflicts:
mm/vmscan.c
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Add a userspace visible knob to tell the VM to keep an extra amount
of memory free, by increasing the gap between each zone's min and
low watermarks.
This is useful for realtime applications that call system
calls and have a bound on the number of allocations that happen
in any short time period. In this application, extra_free_kbytes
would be left at an amount equal to or larger than than the
maximum number of allocations that happen in any burst.
It may also be useful to reduce the memory use of virtual
machines (temporarily?), in a way that does not cause memory
fragmentation like ballooning does.
[ccross]
Revived for use on old kernels where no other solution exists.
The tunable will be removed on kernels that do better at avoiding
direct reclaim.
Change-Id: I765a42be8e964bfd3e2886d1ca85a29d60c3bb3e
Signed-off-by: Rik van Riel<riel@redhat.com>
Signed-off-by: Colin Cross <ccross@android.com>
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Commit c9f01245 ("oom: remove oom_disable_count") has removed the
oom_disable_count counter which has been used for early break out from
oom_badness so we could never select a task with oom_score_adj set to
OOM_SCORE_ADJ_MIN (oom disabled).
Now that the counter is gone we are always going through heuristics
calculation and we always return a non zero positive value. This means
that we can end up killing a task with OOM disabled because it is
indistinguishable from regular tasks with 1% resp. CAP_SYS_ADMIN tasks
with 3% usage of memory or tasks with oom_score_adj set but OOM enabled.
Let's break out early if the task should have OOM disabled.
Signed-off-by: Michal Hocko <mhocko@suse.cz>
Acked-by: David Rientjes <rientjes@google.com>
Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Ying Han <yinghan@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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This removes mm->oom_disable_count entirely since it's unnecessary and
currently buggy. The counter was intended to be per-process but it's
currently decremented in the exit path for each thread that exits, causing
it to underflow.
The count was originally intended to prevent oom killing threads that
share memory with threads that cannot be killed since it doesn't lead to
future memory freeing. The counter could be fixed to represent all
threads sharing the same mm, but it's better to remove the count since:
- it is possible that the OOM_DISABLE thread sharing memory with the
victim is waiting on that thread to exit and will actually cause
future memory freeing, and
- there is no guarantee that a thread is disabled from oom killing just
because another thread sharing its mm is oom disabled.
Signed-off-by: David Rientjes <rientjes@google.com>
Reported-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Cc: Ying Han <yinghan@google.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>
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After selecting a task to kill, the oom killer iterates all processes and
kills all other threads that share the same mm_struct in different thread
groups. It would not otherwise be helpful to kill a thread if its memory
would not be subsequently freed.
A kernel thread, however, may assume a user thread's mm by using
use_mm(). This is only temporary and should not result in sending a
SIGKILL to that kthread.
This patch ensures that only user threads and not kthreads are sent a
SIGKILL if they share the same mm_struct as the oom killed task.
Signed-off-by: David Rientjes <rientjes@google.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Reviewed-by: 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>
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A userspace call to mmap(MAP_LOCKED) may result in the successful locking
of memory while also producing a confusing audit log denial. can_do_mlock
checks capable and rlimit. If either of these return positive
can_do_mlock returns true. The capable check leads to an LSM hook used by
apparmour and selinux which produce the audit denial. Reordering so
rlimit is checked first eliminates the denial on success, only recording a
denial when the lock is unsuccessful as a result of the denial.
Signed-off-by: Jeff Vander Stoep <jeffv@google.com>
Acked-by: Nick Kralevich <nnk@google.com>
Cc: Jeff Vander Stoep <jeffv@google.com>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Paul Cassella <cassella@cray.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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p-android-omap-3.0-dev-espresso
Conflicts:
Makefile
arch/arm/include/asm/hardware/cache-l2x0.h
arch/arm/kernel/smp.c
arch/arm/mach-omap2/board-4430sdp.c
arch/arm/mach-omap2/board-omap4panda.c
arch/arm/mach-omap2/opp.c
arch/ia64/include/asm/futex.h
drivers/bluetooth/ath3k.c
drivers/bluetooth/btusb.c
drivers/firmware/efivars.c
drivers/gpu/drm/i915/intel_lvds.c
drivers/gpu/drm/radeon/radeon_atombios.c
drivers/gpu/drm/radeon/radeon_irq_kms.c
drivers/hwmon/fam15h_power.c
drivers/mfd/twl6030-irq.c
drivers/mmc/core/sdio.c
drivers/net/tun.c
drivers/net/usb/ipheth.c
drivers/net/usb/usbnet.c
drivers/usb/core/hub.c
drivers/usb/host/xhci-mem.c
drivers/usb/host/xhci.h
drivers/usb/musb/omap2430.c
drivers/usb/serial/ftdi_sio.c
drivers/usb/serial/ftdi_sio_ids.h
drivers/usb/serial/option.c
drivers/usb/serial/qcserial.c
drivers/usb/serial/ti_usb_3410_5052.c
drivers/usb/serial/ti_usb_3410_5052.h
drivers/video/omap2/dss/hdmi.c
fs/splice.c
include/asm-generic/pgtable.h
include/net/sch_generic.h
kernel/cgroup.c
kernel/futex.c
kernel/time/timekeeping.c
net/ipv4/route.c
net/ipv4/syncookies.c
net/ipv4/tcp_ipv4.c
net/wireless/util.c
security/commoncap.c
sound/soc/soc-dapm.c
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commit a8f531ebc33052642b4bd7b812eedf397108ce64 upstream.
In collapse_huge_page() there is a race window between releasing the
mmap_sem read lock and taking the mmap_sem write lock, so find_vma() may
return NULL. So check the return value to avoid NULL pointer dereference.
collapse_huge_page
khugepaged_alloc_page
up_read(&mm->mmap_sem)
down_write(&mm->mmap_sem)
vma = find_vma(mm, address)
Signed-off-by: Libin <huawei.libin@huawei.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 2bff24a3707093c435ab3241c47dcdb5f16e432b upstream.
A memory cgroup with (1) multiple threshold notifications and (2) at least
one threshold >=2G was not reliable. Specifically the notifications would
either not fire or would not fire in the proper order.
The __mem_cgroup_threshold() signaling logic depends on keeping 64 bit
thresholds in sorted order. mem_cgroup_usage_register_event() sorts them
with compare_thresholds(), which returns the difference of two 64 bit
thresholds as an int. If the difference is positive but has bit[31] set,
then sort() treats the difference as negative and breaks sort order.
This fix compares the two arbitrary 64 bit thresholds returning the
classic -1, 0, 1 result.
The test below sets two notifications (at 0x1000 and 0x81001000):
cd /sys/fs/cgroup/memory
mkdir x
for x in 4096 2164264960; do
cgroup_event_listener x/memory.usage_in_bytes $x | sed "s/^/$x listener:/" &
done
echo $$ > x/cgroup.procs
anon_leaker 500M
v3.11-rc7 fails to signal the 4096 event listener:
Leaking...
Done leaking pages.
Patched v3.11-rc7 properly notifies:
Leaking...
4096 listener:2013:8:31:14:13:36
Done leaking pages.
The fixed bug is old. It appears to date back to the introduction of
memcg threshold notifications in v2.6.34-rc1-116-g2e72b6347c94 "memcg:
implement memory thresholds"
Signed-off-by: Greg Thelen <gthelen@google.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 3c0b9de6d37a481673e81001c57ca0e410c72346 upstream.
I think we could just move the full vm_iomap_memory() function into
util.h or similar, but I didn't get any reply from anybody actually
using nommu even to this trivial patch, so I'm not going to touch it any
more than required.
Here's the fairly minimal stub to make the nommu case at least
potentially work. It doesn't seem like anybody cares, though.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 13d60f4b6ab5b702dc8d2ee20999f98a93728aec upstream.
The futex_keys of process shared futexes are generated from the page
offset, the mapping host and the mapping index of the futex user space
address. This should result in an unique identifier for each futex.
Though this is not true when futexes are located in different subpages
of an hugepage. The reason is, that the mapping index for all those
futexes evaluates to the index of the base page of the hugetlbfs
mapping. So a futex at offset 0 of the hugepage mapping and another
one at offset PAGE_SIZE of the same hugepage mapping have identical
futex_keys. This happens because the futex code blindly uses
page->index.
Steps to reproduce the bug:
1. Map a file from hugetlbfs. Initialize pthread_mutex1 at offset 0
and pthread_mutex2 at offset PAGE_SIZE of the hugetlbfs
mapping.
The mutexes must be initialized as PTHREAD_PROCESS_SHARED because
PTHREAD_PROCESS_PRIVATE mutexes are not affected by this issue as
their keys solely depend on the user space address.
2. Lock mutex1 and mutex2
3. Create thread1 and in the thread function lock mutex1, which
results in thread1 blocking on the locked mutex1.
4. Create thread2 and in the thread function lock mutex2, which
results in thread2 blocking on the locked mutex2.
5. Unlock mutex2. Despite the fact that mutex2 got unlocked, thread2
still blocks on mutex2 because the futex_key points to mutex1.
To solve this issue we need to take the normal page index of the page
which contains the futex into account, if the futex is in an hugetlbfs
mapping. In other words, we calculate the normal page mapping index of
the subpage in the hugetlbfs mapping.
Mappings which are not based on hugetlbfs are not affected and still
use page->index.
Thanks to Mel Gorman who provided a patch for adding proper evaluation
functions to the hugetlbfs code to avoid exposing hugetlbfs specific
details to the futex code.
[ tglx: Massaged changelog ]
Signed-off-by: Zhang Yi <zhang.yi20@zte.com.cn>
Reviewed-by: Jiang Biao <jiang.biao2@zte.com.cn>
Tested-by: Ma Chenggong <ma.chenggong@zte.com.cn>
Reviewed-by: 'Mel Gorman' <mgorman@suse.de>
Acked-by: 'Darren Hart' <dvhart@linux.intel.com>
Cc: 'Peter Zijlstra' <peterz@infradead.org>
Link: http://lkml.kernel.org/r/000101ce71a6%24a83c5880%24f8b50980%24@com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Mike Galbraith <mgalbraith@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit cea27eb2a202959783f81254c48c250ddd80e129 upstream.
The logic for the memory-remove code fails to correctly account the
Total High Memory when a memory block which contains High Memory is
offlined as shown in the example below. The following patch fixes it.
Before logic memory remove:
MemTotal: 7603740 kB
MemFree: 6329612 kB
Buffers: 94352 kB
Cached: 872008 kB
SwapCached: 0 kB
Active: 626932 kB
Inactive: 519216 kB
Active(anon): 180776 kB
Inactive(anon): 222944 kB
Active(file): 446156 kB
Inactive(file): 296272 kB
Unevictable: 0 kB
Mlocked: 0 kB
HighTotal: 7294672 kB
HighFree: 5704696 kB
LowTotal: 309068 kB
LowFree: 624916 kB
After logic memory remove:
MemTotal: 7079452 kB
MemFree: 5805976 kB
Buffers: 94372 kB
Cached: 872000 kB
SwapCached: 0 kB
Active: 626936 kB
Inactive: 519236 kB
Active(anon): 180780 kB
Inactive(anon): 222944 kB
Active(file): 446156 kB
Inactive(file): 296292 kB
Unevictable: 0 kB
Mlocked: 0 kB
HighTotal: 7294672 kB
HighFree: 5181024 kB
LowTotal: 4294752076 kB
LowFree: 624952 kB
[mhocko@suse.cz: fix CONFIG_HIGHMEM=n build]
Signed-off-by: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: David Rientjes <rientjes@google.com>
Cc: <stable@vger.kernel.org> [2.6.24+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Zhouping Liu <zliu@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 30dad30922ccc733cfdbfe232090cf674dc374dc upstream.
When we have a page fault for the address which is backed by a hugepage
under migration, the kernel can't wait correctly and do busy looping on
hugepage fault until the migration finishes. As a result, users who try
to kick hugepage migration (via soft offlining, for example) occasionally
experience long delay or soft lockup.
This is because pte_offset_map_lock() can't get a correct migration entry
or a correct page table lock for hugepage. This patch introduces
migration_entry_wait_huge() to solve this.
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Reviewed-by: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Andi Kleen <andi@firstfloor.org>
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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discard I/O completion
commit cbab0e4eec299e9059199ebe6daf48730be46d2b upstream.
read_swap_cache_async() can race against get_swap_page(), and stumble
across a SWAP_HAS_CACHE entry in the swap map whose page wasn't brought
into the swapcache yet.
This transient swap_map state is expected to be transitory, but the
actual placement of discard at scan_swap_map() inserts a wait for I/O
completion thus making the thread at read_swap_cache_async() to loop
around its -EEXIST case, while the other end at get_swap_page() is
scheduled away at scan_swap_map(). This can leave the system deadlocked
if the I/O completion happens to be waiting on the CPU waitqueue where
read_swap_cache_async() is busy looping and !CONFIG_PREEMPT.
This patch introduces a cond_resched() call to make the aforementioned
read_swap_cache_async() busy loop condition to bail out when necessary,
thus avoiding the subtle race window.
Signed-off-by: Rafael Aquini <aquini@redhat.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: Hugh Dickins <hughd@google.com>
Cc: Shaohua Li <shli@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 7c3425123ddfdc5f48e7913ff59d908789712b18 upstream.
We should not use set_pmd_at to update pmd_t with pgtable_t pointer.
set_pmd_at is used to set pmd with huge pte entries and architectures
like ppc64, clear few flags from the pte when saving a new entry.
Without this change we observe bad pte errors like below on ppc64 with
THP enabled.
BUG: Bad page map in process ld mm=0xc000001ee39f4780 pte:7fc3f37848000001 pmd:c000001ec0000000
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit d34883d4e35c0a994e91dd847a82b4c9e0c31d83 upstream.
Commit 751efd8610d3 ("mmu_notifier_unregister NULL Pointer deref and
multiple ->release()") breaks the fix 3ad3d901bbcf ("mm: mmu_notifier:
fix freed page still mapped in secondary MMU").
Since hlist_for_each_entry_rcu() is changed now, we can not revert that
patch directly, so this patch reverts the commit and simply fix the bug
spotted by that patch
This bug spotted by commit 751efd8610d3 is:
There is a race condition between mmu_notifier_unregister() and
__mmu_notifier_release().
Assume two tasks, one calling mmu_notifier_unregister() as a result
of a filp_close() ->flush() callout (task A), and the other calling
mmu_notifier_release() from an mmput() (task B).
A B
t1 srcu_read_lock()
t2 if (!hlist_unhashed())
t3 srcu_read_unlock()
t4 srcu_read_lock()
t5 hlist_del_init_rcu()
t6 synchronize_srcu()
t7 srcu_read_unlock()
t8 hlist_del_rcu() <--- NULL pointer deref.
This can be fixed by using hlist_del_init_rcu instead of hlist_del_rcu.
The another issue spotted in the commit is "multiple ->release()
callouts", we needn't care it too much because it is really rare (e.g,
can not happen on kvm since mmu-notify is unregistered after
exit_mmap()) and the later call of multiple ->release should be fast
since all the pages have already been released by the first call.
Anyway, this issue should be fixed in a separate patch.
-stable suggestions: Any version that has commit 751efd8610d3 need to be
backported. I find the oldest version has this commit is 3.0-stable.
[akpm@linux-foundation.org: tweak comments]
Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Tested-by: Robin Holt <holt@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit c2cc499c5bcf9040a738f49e8051b42078205748 upstream.
Page 'new' during MIGRATION can't be flushed with flush_cache_page().
Using flush_cache_page(vma, addr, pfn) is justified only if the page is
already placed in process page table, and that is done right after
flush_cache_page(). But without it the arch function has no knowledge
of process PTE and does nothing.
Besides that, flush_cache_page() flushes an application cache page, but
the kernel has a different page virtual address and dirtied it.
Replace it with flush_dcache_page(new) which is the proper usage.
The old page is flushed in try_to_unmap_one() before migration.
This bug takes place in Sead3 board with M14Kc MIPS CPU without cache
aliasing (but Harvard arch - separate I and D cache) in tight memory
environment (128MB) each 1-3days on SOAK test. It fails in cc1 during
kernel build (SIGILL, SIGBUS, SIGSEG) if CONFIG_COMPACTION is switched
ON.
Signed-off-by: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com>
Cc: Leonid Yegoshin <yegoshin@mips.com>
Acked-by: Rik van Riel <riel@redhat.com>
Cc: Michal Hocko <mhocko@suse.cz>
Acked-by: Mel Gorman <mgorman@suse.de>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: David Miller <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit b4cbb197c7e7a68dbad0d491242e3ca67420c13e upstream.
Various drivers end up replicating the code to mmap() their memory
buffers into user space, and our core memory remapping function may be
very flexible but it is unnecessarily complicated for the common cases
to use.
Our internal VM uses pfn's ("page frame numbers") which simplifies
things for the VM, and allows us to pass physical addresses around in a
denser and more efficient format than passing a "phys_addr_t" around,
and having to shift it up and down by the page size. But it just means
that drivers end up doing that shifting instead at the interface level.
It also means that drivers end up mucking around with internal VM things
like the vma details (vm_pgoff, vm_start/end) way more than they really
need to.
So this just exports a function to map a certain physical memory range
into user space (using a phys_addr_t based interface that is much more
natural for a driver) and hides all the complexity from the driver.
Some drivers will still end up tweaking the vm_page_prot details for
things like prefetching or cacheability etc, but that's actually
relevant to the driver, rather than caring about what the page offset of
the mapping is into the particular IO memory region.
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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commit 9cc3a5bd40067b9a0fbd49199d0780463fc2140f upstream.
With applying the previous patch "hugetlbfs: stop setting VM_DONTDUMP in
initializing vma(VM_HUGETLB)" to reenable hugepage coredump, if a memory
error happens on a hugepage and the affected processes try to access the
error hugepage, we hit VM_BUG_ON(atomic_read(&page->_count) <= 0) in
get_page().
The reason for this bug is that coredump-related code doesn't recognise
"hugepage hwpoison entry" with which a pmd entry is replaced when a memory
error occurs on a hugepage.
In other words, physical address information is stored in different bit
layout between hugepage hwpoison entry and pmd entry, so
follow_hugetlb_page() which is called in get_dump_page() returns a wrong
page from a given address.
The expected behavior is like this:
absent is_swap_pte FOLL_DUMP Expected behavior
-------------------------------------------------------------------
true false false hugetlb_fault
false true false hugetlb_fault
false false false return page
true false true skip page (to avoid allocation)
false true true hugetlb_fault
false false true return page
With this patch, we can call hugetlb_fault() and take proper actions (we
wait for migration entries, fail with VM_FAULT_HWPOISON_LARGE for
hwpoisoned entries,) and as the result we can dump all hugepages except
for hwpoisoned ones.
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Rik van Riel <riel@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com>
Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit b6a9b7f6b1f21735a7456d534dc0e68e61359d2c upstream.
find_vma() can be called by multiple threads with read lock
held on mm->mmap_sem and any of them can update mm->mmap_cache.
Prevent compiler from re-fetching mm->mmap_cache, because other
readers could update it in the meantime:
thread 1 thread 2
|
find_vma() | find_vma()
struct vm_area_struct *vma = NULL; |
vma = mm->mmap_cache; |
if (!(vma && vma->vm_end > addr |
&& vma->vm_start <= addr)) { |
| mm->mmap_cache = vma;
return vma; |
^^ compiler may optimize this |
local variable out and re-read |
mm->mmap_cache |
This issue can be reproduced with gcc-4.8.0-1 on s390x by running
mallocstress testcase from LTP, which triggers:
kernel BUG at mm/rmap.c:1088!
Call Trace:
([<000003d100c57000>] 0x3d100c57000)
[<000000000023a1c0>] do_wp_page+0x2fc/0xa88
[<000000000023baae>] handle_pte_fault+0x41a/0xac8
[<000000000023d832>] handle_mm_fault+0x17a/0x268
[<000000000060507a>] do_protection_exception+0x1e2/0x394
[<0000000000603a04>] pgm_check_handler+0x138/0x13c
[<000003fffcf1f07a>] 0x3fffcf1f07a
Last Breaking-Event-Address:
[<000000000024755e>] page_add_new_anon_rmap+0xc2/0x168
Thanks to Jakub Jelinek for his insight on gcc and helping to
track this down.
Signed-off-by: Jan Stancek <jstancek@redhat.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[bwh: Backported to 3.2: adjust context, indentation]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 08dff7b7d629807dbb1f398c68dd9cd58dd657a1 upstream.
When online_pages() is called to add new memory to an empty zone, it
rebuilds all zone lists by calling build_all_zonelists(). But there's a
bug which prevents the new zone to be added to other nodes' zone lists.
online_pages() {
build_all_zonelists()
.....
node_set_state(zone_to_nid(zone), N_HIGH_MEMORY)
}
Here the node of the zone is put into N_HIGH_MEMORY state after calling
build_all_zonelists(), but build_all_zonelists() only adds zones from
nodes in N_HIGH_MEMORY state to the fallback zone lists.
build_all_zonelists()
->__build_all_zonelists()
->build_zonelists()
->find_next_best_node()
->for_each_node_state(n, N_HIGH_MEMORY)
So memory in the new zone will never be used by other nodes, and it may
cause strange behavor when system is under memory pressure. So put node
into N_HIGH_MEMORY state before calling build_all_zonelists().
Signed-off-by: Jianguo Wu <wujianguo@huawei.com>
Signed-off-by: Jiang Liu <liuj97@gmail.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Keping Chen <chenkeping@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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accouting
commit d00285884c0892bb1310df96bce6056e9ce9b9d9 upstream.
hugetlb_total_pages is used for overcommit calculations but the current
implementation considers only the default hugetlb page size (which is
either the first defined hugepage size or the one specified by
default_hugepagesz kernel boot parameter).
If the system is configured for more than one hugepage size, which is
possible since commit a137e1cc6d6e ("hugetlbfs: per mount huge page
sizes") then the overcommit estimation done by __vm_enough_memory()
(resp. shown by meminfo_proc_show) is not precise - there is an
impression of more available/allowed memory. This can lead to an
unexpected ENOMEM/EFAULT resp. SIGSEGV when memory is accounted.
Testcase:
boot: hugepagesz=1G hugepages=1
the default overcommit ratio is 50
before patch:
egrep 'CommitLimit' /proc/meminfo
CommitLimit: 55434168 kB
after patch:
egrep 'CommitLimit' /proc/meminfo
CommitLimit: 54909880 kB
[akpm@linux-foundation.org: coding-style tweak]
Signed-off-by: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Hillf Danton <dhillf@gmail.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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pages
commit 67d46b296a1ba1477c0df8ff3bc5e0167a0b0732 upstream.
Rob van der Heij reported the following (paraphrased) on private mail.
The scenario is that I want to avoid backups to fill up the page
cache and purge stuff that is more likely to be used again (this is
with s390x Linux on z/VM, so I don't give it as much memory that
we don't care anymore). So I have something with LD_PRELOAD that
intercepts the close() call (from tar, in this case) and issues
a posix_fadvise() just before closing the file.
This mostly works, except for small files (less than 14 pages)
that remains in page cache after the face.
Unfortunately Rob has not had a chance to test this exact patch but the
test program below should be reproducing the problem he described.
The issue is the per-cpu pagevecs for LRU additions. If the pages are
added by one CPU but fadvise() is called on another then the pages
remain resident as the invalidate_mapping_pages() only drains the local
pagevecs via its call to pagevec_release(). The user-visible effect is
that a program that uses fadvise() properly is not obeyed.
A possible fix for this is to put the necessary smarts into
invalidate_mapping_pages() to globally drain the LRU pagevecs if a
pagevec page could not be discarded. The downside with this is that an
inode cache shrink would send a global IPI and memory pressure
potentially causing global IPI storms is very undesirable.
Instead, this patch adds a check during fadvise(POSIX_FADV_DONTNEED) to
check if invalidate_mapping_pages() discarded all the requested pages.
If a subset of pages are discarded it drains the LRU pagevecs and tries
again. If the second attempt fails, it assumes it is due to the pages
being mapped, locked or dirty and does not care. With this patch, an
application using fadvise() correctly will be obeyed but there is a
downside that a malicious application can force the kernel to send
global IPIs and increase overhead.
If accepted, I would like this to be considered as a -stable candidate.
It's not an urgent issue but it's a system call that is not working as
advertised which is weak.
The following test program demonstrates the problem. It should never
report that pages are still resident but will without this patch. It
assumes that CPU 0 and 1 exist.
int main() {
int fd;
int pagesize = getpagesize();
ssize_t written = 0, expected;
char *buf;
unsigned char *vec;
int resident, i;
cpu_set_t set;
/* Prepare a buffer for writing */
expected = FILESIZE_PAGES * pagesize;
buf = malloc(expected + 1);
if (buf == NULL) {
printf("ENOMEM\n");
exit(EXIT_FAILURE);
}
buf[expected] = 0;
memset(buf, 'a', expected);
/* Prepare the mincore vec */
vec = malloc(FILESIZE_PAGES);
if (vec == NULL) {
printf("ENOMEM\n");
exit(EXIT_FAILURE);
}
/* Bind ourselves to CPU 0 */
CPU_ZERO(&set);
CPU_SET(0, &set);
if (sched_setaffinity(getpid(), sizeof(set), &set) == -1) {
perror("sched_setaffinity");
exit(EXIT_FAILURE);
}
/* open file, unlink and write buffer */
fd = open("fadvise-test-file", O_CREAT|O_EXCL|O_RDWR);
if (fd == -1) {
perror("open");
exit(EXIT_FAILURE);
}
unlink("fadvise-test-file");
while (written < expected) {
ssize_t this_write;
this_write = write(fd, buf + written, expected - written);
if (this_write == -1) {
perror("write");
exit(EXIT_FAILURE);
}
written += this_write;
}
free(buf);
/*
* Force ourselves to another CPU. If fadvise only flushes the local
* CPUs pagevecs then the fadvise will fail to discard all file pages
*/
CPU_ZERO(&set);
CPU_SET(1, &set);
if (sched_setaffinity(getpid(), sizeof(set), &set) == -1) {
perror("sched_setaffinity");
exit(EXIT_FAILURE);
}
/* sync and fadvise to discard the page cache */
fsync(fd);
if (posix_fadvise(fd, 0, expected, POSIX_FADV_DONTNEED) == -1) {
perror("posix_fadvise");
exit(EXIT_FAILURE);
}
/* map the file and use mincore to see which parts of it are resident */
buf = mmap(NULL, expected, PROT_READ, MAP_SHARED, fd, 0);
if (buf == NULL) {
perror("mmap");
exit(EXIT_FAILURE);
}
if (mincore(buf, expected, vec) == -1) {
perror("mincore");
exit(EXIT_FAILURE);
}
/* Check residency */
for (i = 0, resident = 0; i < FILESIZE_PAGES; i++) {
if (vec[i])
resident++;
}
if (resident != 0) {
printf("Nr unexpected pages resident: %d\n", resident);
exit(EXIT_FAILURE);
}
munmap(buf, expected);
close(fd);
free(vec);
exit(EXIT_SUCCESS);
}
Signed-off-by: Mel Gorman <mgorman@suse.de>
Reported-by: Rob van der Heij <rvdheij@gmail.com>
Tested-by: Rob van der Heij <rvdheij@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 5f00110f7273f9ff04ac69a5f85bb535a4fd0987 upstream.
The tmpfs remount logic preserves filesystem mempolicy if the mpol=M
option is not specified in the remount request. A new policy can be
specified if mpol=M is given.
Before this patch remounting an mpol bound tmpfs without specifying
mpol= mount option in the remount request would set the filesystem's
mempolicy object to a freed mempolicy object.
To reproduce the problem boot a DEBUG_PAGEALLOC kernel and run:
# mkdir /tmp/x
# mount -t tmpfs -o size=100M,mpol=interleave nodev /tmp/x
# grep /tmp/x /proc/mounts
nodev /tmp/x tmpfs rw,relatime,size=102400k,mpol=interleave:0-3 0 0
# mount -o remount,size=200M nodev /tmp/x
# grep /tmp/x /proc/mounts
nodev /tmp/x tmpfs rw,relatime,size=204800k,mpol=??? 0 0
# note ? garbage in mpol=... output above
# dd if=/dev/zero of=/tmp/x/f count=1
# panic here
Panic:
BUG: unable to handle kernel NULL pointer dereference at (null)
IP: [< (null)>] (null)
[...]
Oops: 0010 [#1] SMP DEBUG_PAGEALLOC
Call Trace:
mpol_shared_policy_init+0xa5/0x160
shmem_get_inode+0x209/0x270
shmem_mknod+0x3e/0xf0
shmem_create+0x18/0x20
vfs_create+0xb5/0x130
do_last+0x9a1/0xea0
path_openat+0xb3/0x4d0
do_filp_open+0x42/0xa0
do_sys_open+0xfe/0x1e0
compat_sys_open+0x1b/0x20
cstar_dispatch+0x7/0x1f
Non-debug kernels will not crash immediately because referencing the
dangling mpol will not cause a fault. Instead the filesystem will
reference a freed mempolicy object, which will cause unpredictable
behavior.
The problem boils down to a dropped mpol reference below if
shmem_parse_options() does not allocate a new mpol:
config = *sbinfo
shmem_parse_options(data, &config, true)
mpol_put(sbinfo->mpol)
sbinfo->mpol = config.mpol /* BUG: saves unreferenced mpol */
This patch avoids the crash by not releasing the mempolicy if
shmem_parse_options() doesn't create a new mpol.
How far back does this issue go? I see it in both 2.6.36 and 3.3. I did
not look back further.
Signed-off-by: Greg Thelen <gthelen@google.com>
Acked-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 751efd8610d3d7d67b7bdf7f62646edea7365dd7 upstream.
There is a race condition between mmu_notifier_unregister() and
__mmu_notifier_release().
Assume two tasks, one calling mmu_notifier_unregister() as a result of a
filp_close() ->flush() callout (task A), and the other calling
mmu_notifier_release() from an mmput() (task B).
A B
t1 srcu_read_lock()
t2 if (!hlist_unhashed())
t3 srcu_read_unlock()
t4 srcu_read_lock()
t5 hlist_del_init_rcu()
t6 synchronize_srcu()
t7 srcu_read_unlock()
t8 hlist_del_rcu() <--- NULL pointer deref.
Additionally, the list traversal in __mmu_notifier_release() is not
protected by the by the mmu_notifier_mm->hlist_lock which can result in
callouts to the ->release() notifier from both mmu_notifier_unregister()
and __mmu_notifier_release().
-stable suggestions:
The stable trees prior to 3.7.y need commits 21a92735f660 and
70400303ce0c cherry-picked in that order prior to cherry-picking this
commit. The 3.7.y tree already has those two commits.
Signed-off-by: Robin Holt <holt@sgi.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Cc: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Cc: Avi Kivity <avi@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Sagi Grimberg <sagig@mellanox.co.il>
Cc: Haggai Eran <haggaie@mellanox.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 70400303ce0c4ced3139499c676d5c79636b0c72 upstream.
The variable must be static especially given the variable name.
s/RCU/SRCU/ over a few comments.
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Cc: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Cc: Sagi Grimberg <sagig@mellanox.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Haggai Eran <haggaie@mellanox.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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schedule
commit 21a92735f660eaecf69a6f2e777f18463760ec32 upstream.
With an RCU based mmu_notifier implementation, any callout to
mmu_notifier_invalidate_range_{start,end}() or
mmu_notifier_invalidate_page() would not be allowed to call schedule()
as that could potentially allow a modification to the mmu_notifier
structure while it is currently being used.
Since srcu allocs 4 machine words per instance per cpu, we may end up
with memory exhaustion if we use srcu per mm. So all mms share a global
srcu. Note that during large mmu_notifier activity exit & unregister
paths might hang for longer periods, but it is tolerable for current
mmu_notifier clients.
Signed-off-by: Sagi Grimberg <sagig@mellanox.co.il>
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Haggai Eran <haggaie@mellanox.com>
Cc: "Paul E. McKenney" <paulmck@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 7c45512df987c5619db041b5c9b80d281e26d3db upstream.
Commit c060f943d092 ("mm: use aligned zone start for pfn_to_bitidx
calculation") fixed out calculation of the index into the pageblock
bitmap when a !SPARSEMEM zome was not aligned to pageblock_nr_pages.
However, the _allocation_ of that bitmap had never taken this alignment
requirement into accout, so depending on the exact size and alignment of
the zone, the use of that index could then access past the allocation,
resulting in some very subtle memory corruption.
This was reported (and bisected) by Ingo Molnar: one of his random
config builds would hang with certain very specific kernel command line
options.
In the meantime, commit c060f943d092 has been marked for stable, so this
fix needs to be back-ported to the stable kernels that backported the
commit to use the right alignment.
Bisected-and-tested-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 1f1d06c34f7675026326cd9f39ff91e4555cf355 upstream.
On COW, a new hugepage is allocated and charged to the memcg. If the
system is oom or the charge to the memcg fails, however, the fault
handler will return VM_FAULT_OOM which results in an oom kill.
Instead, it's possible to fallback to splitting the hugepage so that the
COW results only in an order-0 page being allocated and charged to the
memcg which has a higher liklihood to succeed. This is expensive
because the hugepage must be split in the page fault handler, but it is
much better than unnecessarily oom killing a process.
Signed-off-by: David Rientjes <rientjes@google.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Johannes Weiner <jweiner@redhat.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit c060f943d0929f3e429c5d9522290584f6281d6e upstream.
The current calculation in pfn_to_bitidx assumes that (pfn -
zone->zone_start_pfn) >> pageblock_order will return the same bit for
all pfn in a pageblock. If zone_start_pfn is not aligned to
pageblock_nr_pages, this may not always be correct.
Consider the following with pageblock order = 10, zone start 2MB:
pfn | pfn - zone start | (pfn - zone start) >> page block order
----------------------------------------------------------------
0x26000 | 0x25e00 | 0x97
0x26100 | 0x25f00 | 0x97
0x26200 | 0x26000 | 0x98
0x26300 | 0x26100 | 0x98
This means that calling {get,set}_pageblock_migratetype on a single page
will not set the migratetype for the full block. Fix this by rounding
down zone_start_pfn when doing the bitidx calculation.
For our use case, the effects of this bug were mostly tied to the fact
that CMA allocations would either take a long time or fail to happen.
Depending on the driver using CMA, this could result in anything from
visual glitches to application failures.
Signed-off-by: Laura Abbott <lauraa@codeaurora.org>
Acked-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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