invalidate_bdev() calls cleancache_invalidate_inode() iff ->nrpages != 0
which doen't make any sense.

Make sure that invalidate_bdev() always calls cleancache_invalidate_inode()
regardless of mapping->nrpages value.

Fixes: c515e1fd ("mm/fs: add hooks to support cleancache")
Link: http://lkml.kernel.org/r/20170424164135.22350-3-aryabinin@virtuozzo.comSigned-off-by: NAndrey Ryabinin <aryabinin@virtuozzo.com>
Reviewed-by: NJan Kara <jack@suse.cz>
Acked-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Alexey Kuznetsov <kuznet@virtuozzo.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Nikolay Borisov <n.borisov.lkml@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Patch series "Properly invalidate data in the cleancache", v2.

We've noticed that after direct IO write, buffered read sometimes gets
stale data which is coming from the cleancache.  The reason for this is
that some direct write hooks call call invalidate_inode_pages2[_range]()
conditionally iff mapping->nrpages is not zero, so we may not invalidate
data in the cleancache.

Another odd thing is that we check only for ->nrpages and don't check
for ->nrexceptional, but invalidate_inode_pages2[_range] also
invalidates exceptional entries as well.  So we invalidate exceptional
entries only if ->nrpages != 0? This doesn't feel right.

 - Patch 1 fixes direct IO writes by removing ->nrpages check.
 - Patch 2 fixes similar case in invalidate_bdev().
     Note: I only fixed conditional cleancache_invalidate_inode() here.
       Do we also need to add ->nrexceptional check in into invalidate_bdev()?

 - Patches 3-4: some optimizations.

This patch (of 4):

Some direct IO write fs hooks call invalidate_inode_pages2[_range]()
conditionally iff mapping->nrpages is not zero.  This can't be right,
because invalidate_inode_pages2[_range]() also invalidate data in the
cleancache via cleancache_invalidate_inode() call.  So if page cache is
empty but there is some data in the cleancache, buffered read after
direct IO write would get stale data from the cleancache.

Also it doesn't feel right to check only for ->nrpages because
invalidate_inode_pages2[_range] invalidates exceptional entries as well.

Fix this by calling invalidate_inode_pages2[_range]() regardless of
nrpages state.

Note: nfs,cifs,9p doesn't need similar fix because the never call
cleancache_get_page() (nor directly, nor via mpage_readpage[s]()), so
they are not affected by this bug.

Fixes: c515e1fd ("mm/fs: add hooks to support cleancache")
Link: http://lkml.kernel.org/r/20170424164135.22350-2-aryabinin@virtuozzo.comSigned-off-by: NAndrey Ryabinin <aryabinin@virtuozzo.com>
Reviewed-by: NJan Kara <jack@suse.cz>
Acked-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Alexey Kuznetsov <kuznet@virtuozzo.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Nikolay Borisov <n.borisov.lkml@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

In page_same_filled function, all elements in the page is compared with
next index value.  The current comparison routine compares the (i)th and
(i+1)th values of the page.

In this case, two load operaions occur for each comparison.  But if we
store first value of the page stores at 'val' variable and using it to
compare with others, the load opearation is reduced.  It reduce load
operation per page by up to 64times.

Link: http://lkml.kernel.org/r/1488428104-7257-1-git-send-email-sangwoo2.park@lge.comSigned-off-by: NSangwoo Park <sangwoo2.park@lge.com>
Reviewed-by: NSergey Senozhatsky <sergey.senozhatsky@gmail.com>
Acked-by: NMinchan Kim <minchan@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The zram_free_page already handles NULL handle case and same page so use
it to reduce error probability.  (Acutaully, I made a mistake when I
handled same page feature)

Link: http://lkml.kernel.org/r/1492052365-16169-7-git-send-email-minchan@kernel.orgSigned-off-by: NMinchan Kim <minchan@kernel.org>
Cc: Hannes Reinecke <hare@suse.com>
Cc: Johannes Thumshirn <jthumshirn@suse.de>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

With element, sometime I got confused handle and element access.  It
might be my bad but I think it's time to introduce accessor to prevent
future idiot like me.  This patch is just clean-up patch so it shouldn't
change any behavior.

Link: http://lkml.kernel.org/r/1492052365-16169-6-git-send-email-minchan@kernel.orgSigned-off-by: NMinchan Kim <minchan@kernel.org>
Reviewed-by: NSergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Hannes Reinecke <hare@suse.com>
Cc: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

It's redundant now.  Instead, remove it and use zram structure directly.

Link: http://lkml.kernel.org/r/1492052365-16169-5-git-send-email-minchan@kernel.orgSigned-off-by: NMinchan Kim <minchan@kernel.org>
Cc: Hannes Reinecke <hare@suse.com>
Cc: Johannes Thumshirn <jthumshirn@suse.de>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

With this clean-up phase, I want to use zram's wrapper function to lock
table access which is more consistent with other zram's functions.

Link: http://lkml.kernel.org/r/1492052365-16169-4-git-send-email-minchan@kernel.orgSigned-off-by: NMinchan Kim <minchan@kernel.org>
Reviewed-by: NSergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Hannes Reinecke <hare@suse.com>
Cc: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

For architecture(PAGE_SIZE > 4K), zram have supported partial IO.
However, the mixed code for handling normal/partial IO is too mess,
error-prone to modify IO handler functions with upcoming feature so this
patch aims for cleaning up zram's IO handling functions.

Link: http://lkml.kernel.org/r/1492052365-16169-3-git-send-email-minchan@kernel.orgSigned-off-by: NMinchan Kim <minchan@kernel.org>
Cc: Hannes Reinecke <hare@suse.com>
Cc: Johannes Thumshirn <jthumshirn@suse.de>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Patch series "zram clean up", v2.

This patchset aims to clean up zram .

[1] clean up multiple pages's bvec handling.
[2] clean up partial IO handling
[3-6] clean up zram via using accessor and removing pointless structure.

With [2-6] applied, we can get a few hundred bytes as well as huge
readibility enhance.

x86: 708 byte save

    add/remove: 1/1 grow/shrink: 0/11 up/down: 478/-1186 (-708)
    function                                     old     new   delta
    zram_special_page_read                         -     478    +478
    zram_reset_device                            317     314      -3
    mem_used_max_store                           131     128      -3
    compact_store                                 96      93      -3
    mm_stat_show                                 203     197      -6
    zram_add                                     719     712      -7
    zram_slot_free_notify                        229     214     -15
    zram_make_request                            819     803     -16
    zram_meta_free                               128     111     -17
    zram_free_page                               180     151     -29
    disksize_store                               432     361     -71
    zram_decompress_page.isra                    504       -    -504
    zram_bvec_rw                                2592    2080    -512
    Total: Before=25350773, After=25350065, chg -0.00%

ppc64: 231 byte save

    add/remove: 2/0 grow/shrink: 1/9 up/down: 681/-912 (-231)
    function                                     old     new   delta
    zram_special_page_read                         -     480    +480
    zram_slot_lock                                 -     200    +200
    vermagic                                      39      40      +1
    mm_stat_show                                 256     248      -8
    zram_meta_free                               200     184     -16
    zram_add                                     944     912     -32
    zram_free_page                               348     308     -40
    disksize_store                               572     492     -80
    zram_decompress_page                         664     564    -100
    zram_slot_free_notify                        292     160    -132
    zram_make_request                           1132    1000    -132
    zram_bvec_rw                                2768    2396    -372
    Total: Before=17565825, After=17565594, chg -0.00%

This patch (of 6):

Johannes Thumshirn reported system goes the panic when using NVMe over
Fabrics loopback target with zram.

The reason is zram expects each bvec in bio contains a single page
but nvme can attach a huge bulk of pages attached to the bio's bvec
so that zram's index arithmetic could be wrong so that out-of-bound
access makes system panic.

[1] in mainline solved solved the problem by limiting max_sectors with
SECTORS_PER_PAGE but it makes zram slow because bio should split with
each pages so this patch makes zram aware of multiple pages in a bvec
so it could solve without any regression(ie, bio split).

[1] 0bc31538, zram: set physical queue limits to avoid array out of
    bounds accesses

Link: http://lkml.kernel.org/r/20170413134057.GA27499@bboxSigned-off-by: NMinchan Kim <minchan@kernel.org>
Reported-by: NJohannes Thumshirn <jthumshirn@suse.de>
Tested-by: NJohannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: NJohannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: NSergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Hannes Reinecke <hare@suse.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Commit c0a32fc5 ("mm: more intensive memory corruption debugging")
changed to check debug_guardpage_minorder() > 0 when reporting
allocation failures.  The reasoning was

  When we use guard page to debug memory corruption, it shrinks
  available pages to 1/2, 1/4, 1/8 and so on, depending on parameter
  value. In such case memory allocation failures can be common and
  printing errors can flood dmesg. If somebody debug corruption,
  allocation failures are not the things he/she is interested about.

but this is misguided.

Allocation requests with __GFP_NOWARN flag by definition do not cause
flooding of allocation failure messages.  Allocation requests with
__GFP_NORETRY flag likely also have __GFP_NOWARN flag.  Costly
allocation requests likely also have __GFP_NOWARN flag.

Allocation requests without __GFP_DIRECT_RECLAIM flag likely also have
__GFP_NOWARN flag or __GFP_HIGH flag.  Non-costly allocation requests
with __GFP_DIRECT_RECLAIM flag basically retry forever due to the "too
small to fail" memory-allocation rule.

Therefore, as a whole, shrinking available pages by
debug_guardpage_minorder= kernel boot parameter might cause flooding of
OOM killer messages but unlikely causes flooding of allocation failure
messages.  Let's remove debug_guardpage_minorder() > 0 check which would
likely be pointless.

Link: http://lkml.kernel.org/r/1491910035-4231-1-git-send-email-penguin-kernel@I-love.SAKURA.ne.jpSigned-off-by: NTetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Acked-by: NMichal Hocko <mhocko@suse.com>
Cc: Stanislaw Gruszka <sgruszka@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: "Rafael J . Wysocki" <rafael.j.wysocki@intel.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

It helps to provide page flag description along with the raw value in
error paths during soft offline process.  From sample experiments

Before the patch:

  soft offline: 0x6100: migration failed 1, type 3ffff800008018
  soft offline: 0x7400: migration failed 1, type 3ffff800008018

After the patch:

  soft offline: 0x5900: migration failed 1, type 3ffff800008018 (uptodate|dirty|head)
  soft offline: 0x6c00: migration failed 1, type 3ffff800008018 (uptodate|dirty|head)

Link: http://lkml.kernel.org/r/20170409023829.10788-1-khandual@linux.vnet.ibm.comSigned-off-by: NAnshuman Khandual <khandual@linux.vnet.ibm.com>
Acked-by: NNaoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

madvise_behavior_valid() should be called before acting upon the
behavior parameter.  Hence move up the function.  This also includes
MADV_SOFT_OFFLINE and MADV_HWPOISON options as valid behavior parameter
for the system call madvise().

Link: http://lkml.kernel.org/r/20170418052844.24891-1-khandual@linux.vnet.ibm.comSigned-off-by: NAnshuman Khandual <khandual@linux.vnet.ibm.com>
Acked-by: NDavid Rientjes <rientjes@google.com>
Acked-by: NNaoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This cleans up handling MADV_SOFT_OFFLINE and MADV_HWPOISON called
through madvise() system call.

* madvise_memory_failure() was misleading to accommodate handling of
  both memory_failure() as well as soft_offline_page() functions.
  Basically it handles memory error injection from user space which
  can go either way as memory failure or soft offline. Renamed as
  madvise_inject_error() instead.

* Renamed struct page pointer 'p' to 'page'.

* pr_info() was essentially printing PFN value but it said 'page'
  which was misleading. Made the process virtual address explicit.

Before the patch:

Soft offlining page 0x15e3e at 0x3fff8c230000
Soft offlining page 0x1f3 at 0x3fffa0da0000
Soft offlining page 0x744 at 0x3fff7d200000
Soft offlining page 0x1634d at 0x3fff95e20000
Soft offlining page 0x16349 at 0x3fff95e30000
Soft offlining page 0x1d6 at 0x3fff9e8b0000
Soft offlining page 0x5f3 at 0x3fff91bd0000

Injecting memory failure for page 0x15c8b at 0x3fff83280000
Injecting memory failure for page 0x16190 at 0x3fff83290000
Injecting memory failure for page 0x740 at 0x3fff9a2e0000
Injecting memory failure for page 0x741 at 0x3fff9a2f0000

After the patch:

Soft offlining pfn 0x1484e at process virtual address 0x3fff883c0000
Soft offlining pfn 0x1484f at process virtual address 0x3fff883d0000
Soft offlining pfn 0x14850 at process virtual address 0x3fff883e0000
Soft offlining pfn 0x14851 at process virtual address 0x3fff883f0000
Soft offlining pfn 0x14852 at process virtual address 0x3fff88400000
Soft offlining pfn 0x14853 at process virtual address 0x3fff88410000
Soft offlining pfn 0x14854 at process virtual address 0x3fff88420000
Soft offlining pfn 0x1521c at process virtual address 0x3fff6bc70000

Injecting memory failure for pfn 0x10fcf at process virtual address 0x3fff86310000
Injecting memory failure for pfn 0x10fd0 at process virtual address 0x3fff86320000
Injecting memory failure for pfn 0x10fd1 at process virtual address 0x3fff86330000
Injecting memory failure for pfn 0x10fd2 at process virtual address 0x3fff86340000
Injecting memory failure for pfn 0x10fd3 at process virtual address 0x3fff86350000
Injecting memory failure for pfn 0x10fd4 at process virtual address 0x3fff86360000
Injecting memory failure for pfn 0x10fd5 at process virtual address 0x3fff86370000

Link: http://lkml.kernel.org/r/20170410084701.11248-1-khandual@linux.vnet.ibm.comSigned-off-by: NAnshuman Khandual <khandual@linux.vnet.ibm.com>
Reviewed-by: NNaoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Adding a brief overview of hugetlbfs reservation design and
implementation as an aid to those making code modifications in this
area.

Link: http://lkml.kernel.org/r/1491586995-13085-1-git-send-email-mike.kravetz@oracle.comSigned-off-by: NMike Kravetz <mike.kravetz@oracle.com>
Acked-by: NHillf Danton <hillf.zj@alibaba-inc.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This is a code cleanup patch, no functionality changes.  There are 2
unused function prototype in swap.h, they are removed.

Link: http://lkml.kernel.org/r/20170405071017.23677-1-ying.huang@intel.comSigned-off-by: N"Huang, Ying" <ying.huang@intel.com>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The memory controllers stat function names are awkwardly long and
arbitrarily different from the zone and node stat functions.

The current interface is named:

  mem_cgroup_read_stat()
  mem_cgroup_update_stat()
  mem_cgroup_inc_stat()
  mem_cgroup_dec_stat()
  mem_cgroup_update_page_stat()
  mem_cgroup_inc_page_stat()
  mem_cgroup_dec_page_stat()

This patch renames it to match the corresponding node stat functions:

  memcg_page_state()		[node_page_state()]
  mod_memcg_state()		[mod_node_state()]
  inc_memcg_state()		[inc_node_state()]
  dec_memcg_state()		[dec_node_state()]
  mod_memcg_page_state()	[mod_node_page_state()]
  inc_memcg_page_state()	[inc_node_page_state()]
  dec_memcg_page_state()	[dec_node_page_state()]

Link: http://lkml.kernel.org/r/20170404220148.28338-4-hannes@cmpxchg.orgSigned-off-by: NJohannes Weiner <hannes@cmpxchg.org>
Acked-by: NVladimir Davydov <vdavydov.dev@gmail.com>
Acked-by: NMichal Hocko <mhocko@suse.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The current duplication is a high-maintenance mess, and it's painful to
add new items or query memcg state from the rest of the VM.

This increases the size of the stat array marginally, but we should aim
to track all these stats on a per-cgroup level anyway.

Link: http://lkml.kernel.org/r/20170404220148.28338-3-hannes@cmpxchg.orgSigned-off-by: NJohannes Weiner <hannes@cmpxchg.org>
Acked-by: NVladimir Davydov <vdavydov.dev@gmail.com>
Cc: Michal Hocko <mhocko@suse.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The current duplication is a high-maintenance mess, and it's painful to
add new items.

This increases the size of the event array, but we'll eventually want
most of the VM events tracked on a per-cgroup basis anyway.

Link: http://lkml.kernel.org/r/20170404220148.28338-2-hannes@cmpxchg.orgSigned-off-by: NJohannes Weiner <hannes@cmpxchg.org>
Acked-by: NVladimir Davydov <vdavydov.dev@gmail.com>
Cc: Michal Hocko <mhocko@suse.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

We only ever count single events, drop the @nr parameter.  Rename the
function accordingly.  Remove low-information kerneldoc.

Link: http://lkml.kernel.org/r/20170404220148.28338-1-hannes@cmpxchg.orgSigned-off-by: NJohannes Weiner <hannes@cmpxchg.org>
Acked-by: NVladimir Davydov <vdavydov.dev@gmail.com>
Acked-by: NMichal Hocko <mhocko@suse.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Since commit 59dc76b0 ("mm: vmscan: reduce size of inactive file
list") we noticed bigger IO spikes during changes in cache access
patterns.

The patch in question shrunk the inactive list size to leave more room
for the current workingset in the presence of streaming IO.  However,
workingset transitions that previously happened on the inactive list are
now pushed out of memory and incur more refaults to complete.

This patch disables active list protection when refaults are being
observed.  This accelerates workingset transitions, and allows more of
the new set to establish itself from memory, without eating into the
ability to protect the established workingset during stable periods.

The workloads that were measurably affected for us were hit pretty bad
by it, with refault/majfault rates doubling and tripling during cache
transitions, and the machines sustaining half-hour periods of 100% IO
utilization, where they'd previously have sub-minute peaks at 60-90%.

Stateful services that handle user data tend to be more conservative
with kernel upgrades.  As a result we hit most page cache issues with
some delay, as was the case here.

The severity seemed to warrant a stable tag.

Fixes: 59dc76b0 ("mm: vmscan: reduce size of inactive file list")
Link: http://lkml.kernel.org/r/20170404220052.27593-1-hannes@cmpxchg.orgSigned-off-by: NJohannes Weiner <hannes@cmpxchg.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: <stable@vger.kernel.org>	[4.7+]
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Commit 091d0d55 ("shm: fix null pointer deref when userspace
specifies invalid hugepage size") had replaced MAP_HUGE_MASK with
SHM_HUGE_MASK.  Though both of them contain the same numeric value of
0x3f, MAP_HUGE_MASK flag sounds more appropriate than the other one in
the context.  Hence change it back.

Link: http://lkml.kernel.org/r/20170404045635.616-1-khandual@linux.vnet.ibm.comSigned-off-by: NAnshuman Khandual <khandual@linux.vnet.ibm.com>
Reviewed-by: NMatthew Wilcox <mawilcox@microsoft.com>
Acked-by: NBalbir Singh <bsingharora@gmail.com>
Acked-by: NMichal Hocko <mhocko@suse.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Tetsuo has reported that sysrq triggered OOM killer will print a
misleading information when no tasks are selected:

  sysrq: SysRq : Manual OOM execution
  Out of memory: Kill process 4468 ((agetty)) score 0 or sacrifice child
  Killed process 4468 ((agetty)) total-vm:43704kB, anon-rss:1760kB, file-rss:0kB, shmem-rss:0kB
  sysrq: SysRq : Manual OOM execution
  Out of memory: Kill process 4469 (systemd-cgroups) score 0 or sacrifice child
  Killed process 4469 (systemd-cgroups) total-vm:10704kB, anon-rss:120kB, file-rss:0kB, shmem-rss:0kB
  sysrq: SysRq : Manual OOM execution
  sysrq: OOM request ignored because killer is disabled
  sysrq: SysRq : Manual OOM execution
  sysrq: OOM request ignored because killer is disabled
  sysrq: SysRq : Manual OOM execution
  sysrq: OOM request ignored because killer is disabled

The real reason is that there are no eligible tasks for the OOM killer
to select but since commit 7c5f64f8 ("mm: oom: deduplicate victim
selection code for memcg and global oom") the semantic of out_of_memory
has changed without updating moom_callback.

This patch updates moom_callback to tell that no task was eligible which
is the case for both oom killer disabled and no eligible tasks.  In
order to help distinguish first case from the second add printk to both
oom_killer_{enable,disable}.  This information is useful on its own
because it might help debugging potential memory allocation failures.

Fixes: 7c5f64f8 ("mm: oom: deduplicate victim selection code for memcg and global oom")
Link: http://lkml.kernel.org/r/20170404134705.6361-1-mhocko@kernel.orgSigned-off-by: NMichal Hocko <mhocko@suse.com>
Reported-by: NTetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Currently, selftest for userfaultfd is compiled three times: for
anonymous, shared and hugetlb memory.  Let's combine all the cases into
a single executable which will have a command line option for selection
of the test type.

Link: http://lkml.kernel.org/r/1490869741-5913-1-git-send-email-rppt@linux.vnet.ibm.comSigned-off-by: NMike Rapoport <rppt@linux.vnet.ibm.com>
Reviewed-by: NMike Kravetz <mike.kravetz@oracle.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Fix variable name error in comments. No code changes.

Link: http://lkml.kernel.org/r/20170403161655.5081-1-haolee.swjtu@gmail.comSigned-off-by: NHao Lee <haolee.swjtu@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Add a warning diagnostics to user if we failed to allocate swap slots
cache and use it.

[akpm@linux-foundation.org: use WARN_ONCE return value, fix grammar in message]
Link: http://lkml.kernel.org/r/20170328234827.GA10107@linux.intel.comSigned-off-by: NTim Chen <tim.c.chen@linux.intel.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

It is preferred, and the rest of migrate.h gets it right.

Link: http://lkml.kernel.org/r/1490336009-8024-1-git-send-email-pushkar.iit@gmail.comSigned-off-by: NPushkar Jambhlekar <pushkar.iit@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

On SPARSEMEM systems page poisoning is enabled after buddy is up,
because of the dependency on page extension init.  This causes the pages
released by free_all_bootmem not to be poisoned.  This either delays or
misses the identification of some issues because the pages have to
undergo another cycle of alloc-free-alloc for any corruption to be
detected.

Enable page poisoning early by getting rid of the PAGE_EXT_DEBUG_POISON
flag.  Since all the free pages will now be poisoned, the flag need not
be verified before checking the poison during an alloc.

[vinmenon@codeaurora.org: fix Kconfig]
  Link: http://lkml.kernel.org/r/1490878002-14423-1-git-send-email-vinmenon@codeaurora.org
Link: http://lkml.kernel.org/r/1490358246-11001-1-git-send-email-vinmenon@codeaurora.orgSigned-off-by: NVinayak Menon <vinmenon@codeaurora.org>
Acked-by: NLaura Abbott <labbott@redhat.com>
Tested-by: NLaura Abbott <labbott@redhat.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Cluster lock is used to protect the swap_cluster_info and corresponding
elements in swap_info_struct->swap_map[].  But it is found that now in
scan_swap_map_slots(), swap_avail_lock may be acquired when cluster lock
is held.  This does no good except making the locking more complex and
improving the potential locking contention, because the
swap_info_struct->lock is used to protect the data structure operated in
the code already.  Fix this via moving the corresponding operations in
scan_swap_map_slots() out of cluster lock.

Link: http://lkml.kernel.org/r/20170317064635.12792-3-ying.huang@intel.comSigned-off-by: N"Huang, Ying" <ying.huang@intel.com>
Acked-by: NTim Chen <tim.c.chen@intel.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This is just a cleanup patch, no functionality change.

In cluster_list_add_tail(), spin_lock_nested() is used to lock the
cluster, while unlock_cluster() is used to unlock the cluster.  To
improve the code readability, use spin_unlock() directly to unlock the
cluster.

Link: http://lkml.kernel.org/r/20170317064635.12792-2-ying.huang@intel.comSigned-off-by: N"Huang, Ying" <ying.huang@intel.com>
Acked-by: NTim Chen <tim.c.chen@intel.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Commit cbab0e4e ("swap: avoid read_swap_cache_async() race to
deadlock while waiting on discard I/O completion") fixed a deadlock in
read_swap_cache_async().  Because at that time, in swap allocation path,
a swap entry may be set as SWAP_HAS_CACHE, then wait for discarding to
complete before the page for the swap entry is added to the swap cache.

But in commit 815c2c54 ("swap: make swap discard async"), the
discarding for swap become asynchronous, waiting for discarding to
complete will be done before the swap entry is set as SWAP_HAS_CACHE.
So the comments in code is incorrect now.  This patch fixes the
comments.

The cond_resched() added in the commit cbab0e4e is not necessary now
too.  But if we added some sleep in swap allocation path in the future,
there may be some hard to debug/reproduce deadlock bug.  So it is kept.

Link: http://lkml.kernel.org/r/20170317064635.12792-1-ying.huang@intel.comSigned-off-by: N"Huang, Ying" <ying.huang@intel.com>
Acked-by: NRafael Aquini <aquini@redhat.com>
Cc: Shaohua Li <shli@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

There is no user for it.  Remove it.

[minchan@kernel.org: use false instead of SWAP_FAIL]
  Link: http://lkml.kernel.org/r/20170316053313.GA19241@bbox
Link: http://lkml.kernel.org/r/1489555493-14659-11-git-send-email-minchan@kernel.orgSigned-off-by: NMinchan Kim <minchan@kernel.org>
Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Cc: Hillf Danton <hillf.zj@alibaba-inc.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

rmap_one's return value controls whether rmap_work should contine to
scan other ptes or not so it's target for changing to boolean.  Return
true if the scan should be continued.  Otherwise, return false to stop
the scanning.

This patch makes rmap_one's return value to boolean.

Link: http://lkml.kernel.org/r/1489555493-14659-10-git-send-email-minchan@kernel.orgSigned-off-by: NMinchan Kim <minchan@kernel.org>
Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Cc: Hillf Danton <hillf.zj@alibaba-inc.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

There is no user of the return value from rmap_walk() and friends so
this patch makes them void-returning functions.

Link: http://lkml.kernel.org/r/1489555493-14659-9-git-send-email-minchan@kernel.orgSigned-off-by: NMinchan Kim <minchan@kernel.org>
Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Cc: Hillf Danton <hillf.zj@alibaba-inc.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

try_to_unmap() returns SWAP_SUCCESS or SWAP_FAIL so it's suitable for
boolean return.  This patch changes it.

Link: http://lkml.kernel.org/r/1489555493-14659-8-git-send-email-minchan@kernel.orgSigned-off-by: NMinchan Kim <minchan@kernel.org>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Cc: Hillf Danton <hillf.zj@alibaba-inc.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

In 2002, [1] introduced SWAP_AGAIN.  At that time, try_to_unmap_one used
spin_trylock(&mm->page_table_lock) so it's really easy to contend and
fail to hold a lock so SWAP_AGAIN to keep LRU status makes sense.

However, now we changed it to mutex-based lock and be able to block
without skip pte so there is few of small window to return SWAP_AGAIN so
remove SWAP_AGAIN and just return SWAP_FAIL.

[1] c48c43e4, minimal rmap

Link: http://lkml.kernel.org/r/1489555493-14659-7-git-send-email-minchan@kernel.orgSigned-off-by: NMinchan Kim <minchan@kernel.org>
Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Cc: Hillf Danton <hillf.zj@alibaba-inc.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

ttu doesn't need to return SWAP_MLOCK.  Instead, just return SWAP_FAIL
because it means the page is not-swappable so it should move to another
LRU list(active or unevictable).  putback friends will move it to right
list depending on the page's LRU flag.

Link: http://lkml.kernel.org/r/1489555493-14659-6-git-send-email-minchan@kernel.orgSigned-off-by: NMinchan Kim <minchan@kernel.org>
Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Cc: Hillf Danton <hillf.zj@alibaba-inc.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

try_to_munlock returns SWAP_MLOCK if the one of VMAs mapped the page has
VM_LOCKED flag.  In that time, VM set PG_mlocked to the page if the page
is not pte-mapped THP which cannot be mlocked, either.

With that, __munlock_isolated_page can use PageMlocked to check whether
try_to_munlock is successful or not without relying on try_to_munlock's
retval.  It helps to make try_to_unmap/try_to_unmap_one simple with
upcoming patches.

[minchan@kernel.org: remove PG_Mlocked VM_BUG_ON check]
  Link: http://lkml.kernel.org/r/20170411025615.GA6545@bbox
Link: http://lkml.kernel.org/r/1489555493-14659-5-git-send-email-minchan@kernel.orgSigned-off-by: NMinchan Kim <minchan@kernel.org>
Acked-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: NVlastimil Babka <vbabka@suse.cz>
Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Cc: Hillf Danton <hillf.zj@alibaba-inc.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

If the page is mapped and rescue in try_to_unmap_one, the
page_mapcount() of a page cannot be zero, so the page_mapcount check in
try_to_unmap is enough to return SWAP_SUCCESS.  IOW, SWAP_MLOCK check is
redundant so remove it.

Link: http://lkml.kernel.org/r/1489555493-14659-4-git-send-email-minchan@kernel.orgSigned-off-by: NMinchan Kim <minchan@kernel.org>
Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Cc: Hillf Danton <hillf.zj@alibaba-inc.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

If we found lazyfree page is dirty, try_to_unmap_one can just
SetPageSwapBakced in there like PG_mlocked page and just return with
SWAP_FAIL which is very natural because the page is not swappable right
now so that vmscan can activate it.  There is no point to introduce new
return value SWAP_DIRTY in try_to_unmap at the moment.

Link: http://lkml.kernel.org/r/1489555493-14659-3-git-send-email-minchan@kernel.orgSigned-off-by: NMinchan Kim <minchan@kernel.org>
Acked-by: NHillf Danton <hillf.zj@alibaba-inc.com>
Acked-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Nobody uses ret variable. Remove it.

Link: http://lkml.kernel.org/r/1489555493-14659-2-git-send-email-minchan@kernel.orgSigned-off-by: NMinchan Kim <minchan@kernel.org>
Acked-by: NHillf Danton <hillf.zj@alibaba-inc.com>
Acked-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>