Commit Graph

463290 Commits

Author SHA1 Message Date
Hugh Dickins
eb39d618f9 mm: replace init_page_accessed by __SetPageReferenced
Do we really need an exported alias for __SetPageReferenced()? Its
callers better know what they're doing, in which case the page would not
be already marked referenced.  Kill init_page_accessed(), just
__SetPageReferenced() inline.

Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Prabhakar Lad <prabhakar.csengg@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-06 18:01:19 -07:00
Fabian Frederick
c2ea2181db mm/hwpoison-inject.c: remove unnecessary null test before debugfs_remove_recursive
Fix checkpatch warning:
  "WARNING: debugfs_remove_recursive(NULL) is safe this check is probably not required"

Signed-off-by: Fabian Frederick <fabf@skynet.be>
Acked-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-06 18:01:19 -07:00
Rafael Aquini
cc7452b6dc mm: export NR_SHMEM via sysinfo(2) / si_meminfo() interfaces
Historically, we exported shared pages to userspace via sysinfo(2)
sharedram and /proc/meminfo's "MemShared" fields.  With the advent of
tmpfs, from kernel v2.4 onward, that old way for accounting shared mem
was deemed inaccurate and we started to export a hard-coded 0 for
sysinfo.sharedram.  Later on, during the 2.6 timeframe, "MemShared" got
re-introduced to /proc/meminfo re-branded as "Shmem", but we're still
reporting sysinfo.sharedmem as that old hard-coded zero, which makes the
"shared memory" report inconsistent across interfaces.

This patch leverages the addition of explicit accounting for pages used
by shmem/tmpfs -- "4b02108 mm: oom analysis: add shmem vmstat" -- in
order to make the users of sysinfo(2) and si_meminfo*() friends aware of
that vmstat entry and make them report it consistently across the
interfaces, as well to make sysinfo(2) returned data consistent with our
current API documentation states.

Signed-off-by: Rafael Aquini <aquini@redhat.com>
Acked-by: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-06 18:01:19 -07:00
Konstantin Khlebnikov
82f71ae4a2 mm: catch memory commitment underflow
Print a warning (if CONFIG_DEBUG_VM=y) when memory commitment becomes
too negative.

This shouldn't happen any more - the previous two patches fixed the
committed_as underflow issues.

[akpm@linux-foundation.org: use VM_WARN_ONCE, per Dave]
Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-06 18:01:19 -07:00
Konstantin Khlebnikov
7714251799 shmem: update memory reservation on truncate
A shared anonymous mapping created without MAP_NORESERVE holds memory
reservation for whole range of shmem segment.  Usually there is no way
to change its size, but /proc/<pid>/map_files/...  (available if
CONFIG_CHECKPOINT_RESTORE=y) allows that.

This patch adjusts the memory reservation in shmem_setattr().

Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.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>
2014-08-06 18:01:19 -07:00
Konstantin Khlebnikov
66ee4b8887 shmem: fix double uncharge in __shmem_file_setup()
If __shmem_file_setup() fails on struct file allocation it uncharges
memory commitment twice: first by shmem_unacct_size() and second time
implicitly in shmem_evict_inode() when it kills the newly created inode.

This patch removes shmem_unacct_size() from error path if the inode was
already there.

Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.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>
2014-08-06 18:01:18 -07:00
Andrew Morton
ef6b571fb8 include/linux/mmdebug.h: add VM_WARN_ONCE()
It was missing...

Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-06 18:01:18 -07:00
David Rientjes
930f036b4f mm, vmalloc: constify allocation mask
tmp_mask in the __vmalloc_area_node() iteration never changes so it can
be moved into function scope and marked with const.  This causes the
movl and orl to only be done once per call rather than area->nr_pages
times.

nested_gfp can also be marked const.

Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-06 18:01:18 -07:00
Eric Dumazet
660654f90e mm/vmalloc.c: add a schedule point to vmalloc()
It is not uncommon on busy servers to get stuck hundred of ms in
vmalloc() calls (like file descriptor expansions).

Add a cond_resched() to __vmalloc_area_node() to be gentle to
other tasks.

[akpm@linux-foundation.org: only do it for __GFP_WAIT, per David]
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Hugh Dickins <hughd@google.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>
2014-08-06 18:01:18 -07:00
Wang Sheng-Hui
54980b93c0 mm: update the description for madvise_remove
Currently, we have more filesystems supporting fallocate, e.g
ext4/btrfs.  Remove the outdated comment for madvise_remove.

Signed-off-by: Wang Sheng-Hui <shhuiw@gmail.com>
Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-06 18:01:18 -07:00
Max Asbock
4a262d2658 mm tracing: tell mm_migrate_pages event about numa_misplaced
The mm_migrate_pages trace event reports a reason for the migration,
typically as a symbolic string.  The exception is the reason
MR_NUMA_MISPLACED for which it just displays the numeric value:
mm_migrate_pages: nr_succeeded=1 nr_failed=0 mode=MIGRATE_ASYNC
reason=0x5

This patch makes the output consistent by introducing a string value for
MR_NUMA_MISPLACED.  The event is then reported as: mm_migrate_pages:
nr_succeeded=1 nr_failed=0 mode=MIGRATE_ASYNC reason=numa_misplaced

Signed-off-by: Max Asbock <masbock@linux.vnet.ibm.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Ingo Molnar <mingo@redhat.com>
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>
2014-08-06 18:01:18 -07:00
Johannes Weiner
ee814fe23d mm: vmscan: clean up struct scan_control
Reorder the members by input and output, then turn the individual
integers for may_writepage, may_unmap, may_swap, compaction_ready,
hibernation_mode into bit fields to save stack space:

  +72/-296 -224
  kswapd                                       104     176     +72
  try_to_free_pages                             80      56     -24
  try_to_free_mem_cgroup_pages                  80      56     -24
  shrink_all_memory                             88      64     -24
  reclaim_clean_pages_from_list                168     144     -24
  mem_cgroup_shrink_node_zone                  104      80     -24
  __zone_reclaim                               176     152     -24
  balance_pgdat                                152       -    -152

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Suggested-by: Mel Gorman <mgorman@suse.de>
Acked-by: Mel Gorman <mgorman@suse.de>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Minchan Kim <minchan.kim@gmail.com>
Cc: Rik van Riel <riel@redhat.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>
2014-08-06 18:01:18 -07:00
Johannes Weiner
02695175c7 mm: vmscan: move swappiness out of scan_control
Swappiness is determined for each scanned memcg individually in
shrink_zone() and is not a parameter that applies throughout the reclaim
scan.  Move it out of struct scan_control to prevent accidental use of a
stale value.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-06 18:01:18 -07:00
Johannes Weiner
2344d7e44b mm: vmscan: remove all_unreclaimable()
Direct reclaim currently calls shrink_zones() to reclaim all members of
a zonelist, and if that wasn't successful it does another pass through
the same zonelist to check overall reclaimability.

Just check reclaimability in shrink_zones() directly and propagate the
result through the return value.  Then remove all_unreclaimable().

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-06 18:01:18 -07:00
Johannes Weiner
0b06496a33 mm: vmscan: rework compaction-ready signaling in direct reclaim
Page reclaim for a higher-order page runs until compaction is ready,
then aborts and signals this situation through the return value of
shrink_zones().  This is an oddly specific signal to encode in the
return value of shrink_zones(), though, and can be quite confusing.

Introduce sc->compaction_ready and signal the compactability of the
zones out-of-band to free up the return value of shrink_zones() for
actual zone reclaimability.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Michal Hocko <mhocko@suse.cz>
Acked-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-06 18:01:18 -07:00
Johannes Weiner
8d07429319 mm: vmscan: remove remains of kswapd-managed zone->all_unreclaimable
shrink_zones() has a special branch to skip the all_unreclaimable()
check during hibernation, because a frozen kswapd can't mark a zone
unreclaimable.

But ever since commit 6e543d5780 ("mm: vmscan: fix
do_try_to_free_pages() livelock"), determining a zone to be
unreclaimable is done by directly looking at its scan history and no
longer relies on kswapd setting the per-zone flag.

Remove this branch and let shrink_zones() check the reclaimability of
the target zones regardless of hibernation state.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Minchan Kim <minchan@kernel.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>
2014-08-06 18:01:18 -07:00
Wang Nan
1a4dc5bc7c mem-hotplug: improve zone_movable_is_highmem logic
In original code, zone_movable_is_highmem() assumes ZONE_MOVABLE not
highmem if CONFIG_HAVE_MEMBLOCK_NODE_MAP is not set.  In online_pages,
it extracts pages from the previous zone before ZONE_MOVABLE.  Which is
logically inconsistent:

If HAVE_MEMBLOCK_NODE_MAP is turned off but HIGHMEM is on,
zone_movable_is_highmem() makes movable zone not highmem, but
online_pages() extracts pages from ZONE_HIGHMEM.

This inconsistency doesn't cause real problem currently, because all
architectures support online_pages also have HAVE_MEMBLOCK_NODE_MAP.
However, fixing it makes code clear, and also helps futher coding.

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Cc: Zhang Zhen <zhangzhen@huawei.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Jiang Liu <liuj97@gmail.com>
Cc: Li Zefan <lizefan@huawei.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-06 18:01:18 -07:00
Zhang Zhen
b69deb2b7e mm/mem-hotplug: replace simple_strtoull() with kstrtoull()
Use the newer and more pleasant kstrtoull() to replace
simple_strtoull(), because simple_strtoull() is marked for obsoletion.

Signed-off-by: Zhang Zhen <zhenzhang.zhang@huawei.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>
2014-08-06 18:01:18 -07:00
Johannes Weiner
a840cda63e mm: memcontrol: do not acquire page_cgroup lock for kmem pages
Kmem page charging and uncharging is serialized by means of exclusive
access to the page.  Do not take the page_cgroup lock and don't set
pc->flags atomically.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Vladimir Davydov <vdavydov@parallels.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-06 18:01:17 -07:00
Johannes Weiner
9a2385eef9 mm: memcontrol: remove ordering between pc->mem_cgroup and PageCgroupUsed
There is a write barrier between setting pc->mem_cgroup and
PageCgroupUsed, which was added to allow LRU operations to lookup the
memcg LRU list of a page without acquiring the page_cgroup lock.

But ever since commit 38c5d72f3e ("memcg: simplify LRU handling by new
rule"), pages are ensured to be off-LRU while charging, so nobody else
is changing LRU state while pc->mem_cgroup is being written, and there
are no read barriers anymore.

Remove the unnecessary write barrier.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Hugh Dickins <hughd@google.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Vladimir Davydov <vdavydov@parallels.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-06 18:01:17 -07:00
Johannes Weiner
05b8430123 mm: memcontrol: use root_mem_cgroup res_counter
Due to an old optimization to keep expensive res_counter changes at a
minimum, the root_mem_cgroup res_counter is never charged; there is no
limit at that level anyway, and any statistics can be generated on
demand by summing up the counters of all other cgroups.

However, with per-cpu charge caches, res_counter operations do not even
show up in profiles anymore, so this optimization is no longer
necessary.

Remove it to simplify the code.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Vladimir Davydov <vdavydov@parallels.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-06 18:01:17 -07:00
Johannes Weiner
692e7c45d9 mm: memcontrol: catch root bypass in move precharge
When mem_cgroup_try_charge() returns -EINTR, it bypassed the charge to
the root memcg.  But move precharging does not catch this and treats
this case as if no charge had happened, thus leaking a charge against
root.  Because of an old optimization, the root memcg's res_counter is
not actually charged right now, but it's still an imbalance and
subsequent patches will charge the root memcg again.

Catch those bypasses to the root memcg and properly cancel them before
giving up the move.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Hugh Dickins <hughd@google.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Vladimir Davydov <vdavydov@parallels.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-06 18:01:17 -07:00
Johannes Weiner
9476db974d mm: memcontrol: simplify move precharge function
The move precharge function does some baroque things: it tries raw
res_counter charging of the entire amount first, and then falls back to
a loop of one-by-one charges, with checks for pending signals and
cond_resched() batching.

Just use mem_cgroup_try_charge() without __GFP_WAIT for the first bulk
charge attempt.  In the one-by-one loop, remove the signal check (this
is already checked in try_charge), and simply call cond_resched() after
every charge - it's not that expensive.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Hugh Dickins <hughd@google.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Vladimir Davydov <vdavydov@parallels.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-06 18:01:17 -07:00
Michal Hocko
0029e19ebf mm: memcontrol: remove explicit OOM parameter in charge path
For the page allocator, __GFP_NORETRY implies that no OOM should be
triggered, whereas memcg has an explicit parameter to disable OOM.

The only callsites that want OOM disabled are THP charges and charge
moving.  THP already uses __GFP_NORETRY and charge moving can use it as
well - one full reclaim cycle should be plenty.  Switch it over, then
remove the OOM parameter.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Michal Hocko <mhocko@suse.cz>
Cc: Hugh Dickins <hughd@google.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Vladimir Davydov <vdavydov@parallels.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-06 18:01:17 -07:00
Johannes Weiner
9b1306192d mm: memcontrol: retry reclaim for oom-disabled and __GFP_NOFAIL charges
There is no reason why oom-disabled and __GFP_NOFAIL charges should try
to reclaim only once when every other charge tries several times before
giving up.  Make them all retry the same number of times.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Hugh Dickins <hughd@google.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Vladimir Davydov <vdavydov@parallels.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-06 18:01:17 -07:00
Johannes Weiner
d51d885bbb mm: huge_memory: use GFP_TRANSHUGE when charging huge pages
Transparent huge page charges prefer falling back to regular pages
rather than spending a lot of time in direct reclaim.

Desired reclaim behavior is usually declared in the gfp mask, but THP
charges use GFP_KERNEL and then rely on the fact that OOM is disabled
for THP charges, and that OOM-disabled charges don't retry reclaim.
Needless to say, this is anything but obvious and quite error prone.

Convert THP charges to use GFP_TRANSHUGE instead, which implies
__GFP_NORETRY, to indicate the low-latency requirement.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Hugh Dickins <hughd@google.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Vladimir Davydov <vdavydov@parallels.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-06 18:01:17 -07:00
Johannes Weiner
28c34c291e mm: memcontrol: reclaim at least once for __GFP_NORETRY
Currently, __GFP_NORETRY tries charging once and gives up before even
trying to reclaim.  Bring the behavior on par with the page allocator
and reclaim at least once before giving up.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Hugh Dickins <hughd@google.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Vladimir Davydov <vdavydov@parallels.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-06 18:01:17 -07:00
Johannes Weiner
06b078fc06 mm: memcontrol: rearrange charging fast path
The charging path currently starts out with OOM condition checks when
OOM is the rarest possible case.

Rearrange this code to run OOM/task dying checks only after trying the
percpu charge and the res_counter charge and bail out before entering
reclaim.  Attempting a charge does not hurt an (oom-)killed task as much
as every charge attempt having to check OOM conditions.  Also, only
check __GFP_NOFAIL when the charge would actually fail.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Hugh Dickins <hughd@google.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Vladimir Davydov <vdavydov@parallels.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-06 18:01:17 -07:00
Johannes Weiner
6539cc0538 mm: memcontrol: fold mem_cgroup_do_charge()
These patches rework memcg charge lifetime to integrate more naturally
with the lifetime of user pages.  This drastically simplifies the code
and reduces charging and uncharging overhead.  The most expensive part
of charging and uncharging is the page_cgroup bit spinlock, which is
removed entirely after this series.

Here are the top-10 profile entries of a stress test that reads a 128G
sparse file on a freshly booted box, without even a dedicated cgroup
(i.e. executing in the root memcg).  Before:

    15.36%              cat  [kernel.kallsyms]   [k] copy_user_generic_string
    13.31%              cat  [kernel.kallsyms]   [k] memset
    11.48%              cat  [kernel.kallsyms]   [k] do_mpage_readpage
     4.23%              cat  [kernel.kallsyms]   [k] get_page_from_freelist
     2.38%              cat  [kernel.kallsyms]   [k] put_page
     2.32%              cat  [kernel.kallsyms]   [k] __mem_cgroup_commit_charge
     2.18%          kswapd0  [kernel.kallsyms]   [k] __mem_cgroup_uncharge_common
     1.92%          kswapd0  [kernel.kallsyms]   [k] shrink_page_list
     1.86%              cat  [kernel.kallsyms]   [k] __radix_tree_lookup
     1.62%              cat  [kernel.kallsyms]   [k] __pagevec_lru_add_fn

After:

    15.67%           cat  [kernel.kallsyms]   [k] copy_user_generic_string
    13.48%           cat  [kernel.kallsyms]   [k] memset
    11.42%           cat  [kernel.kallsyms]   [k] do_mpage_readpage
     3.98%           cat  [kernel.kallsyms]   [k] get_page_from_freelist
     2.46%           cat  [kernel.kallsyms]   [k] put_page
     2.13%       kswapd0  [kernel.kallsyms]   [k] shrink_page_list
     1.88%           cat  [kernel.kallsyms]   [k] __radix_tree_lookup
     1.67%           cat  [kernel.kallsyms]   [k] __pagevec_lru_add_fn
     1.39%       kswapd0  [kernel.kallsyms]   [k] free_pcppages_bulk
     1.30%           cat  [kernel.kallsyms]   [k] kfree

As you can see, the memcg footprint has shrunk quite a bit.

   text    data     bss     dec     hex filename
  37970    9892     400   48262    bc86 mm/memcontrol.o.old
  35239    9892     400   45531    b1db mm/memcontrol.o

This patch (of 13):

This function was split out because mem_cgroup_try_charge() got too big.
But having essentially one sequence of operations arbitrarily split in
half is not good for reworking the code.  Fold it back in.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Hugh Dickins <hughd@google.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Vladimir Davydov <vdavydov@parallels.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-06 18:01:17 -07:00
Johannes Weiner
2f3e442ccc mm: page-flags: clean up the page flag test, set, clear macros
- PAGEFLAG_FALSE only defines TEST, make it define SET and CLEAR as
  well, analogous to PAGEFLAG.

- Define TESTSETFLAG_FALSE, analogous to TESTSETFLAG.

- Define TESTSCFLAG_FALSE, analogous to TESTSCFLAG

- Make PG_mlocked accessors the same on both MMU and !MMU setups

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-06 18:01:17 -07:00
Waiman Long
3a79d52aa3 mm, thp: replace smp_mb after atomic_add by smp_mb__after_atomic
In some architectures like x86, atomic_add() is a full memory barrier.
In that case, an additional smp_mb() is just a waste of time.  This
patch replaces that smp_mb() by smp_mb__after_atomic() which will avoid
the redundant memory barrier in some architectures.

With a 3.16-rc1 based kernel, this patch reduced the execution time of
breaking 1000 transparent huge pages from 38,245us to 30,964us.  A
reduction of 19% which is quite sizeable.  It also reduces the %cpu time
of the __split_huge_page_refcount function in the perf profile from
2.18% to 1.15%.

Signed-off-by: Waiman Long <Waiman.Long@hp.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Scott J Norton <scott.norton@hp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-06 18:01:17 -07:00
Waiman Long
f8303c2582 mm, thp: move invariant bug check out of loop in __split_huge_page_map
In __split_huge_page_map(), the check for page_mapcount(page) is
invariant within the for loop.  Because of the fact that the macro is
implemented using atomic_read(), the redundant check cannot be optimized
away by the compiler leading to unnecessary read to the page structure.

This patch moves the invariant bug check out of the loop so that it will
be done only once.  On a 3.16-rc1 based kernel, the execution time of a
microbenchmark that broke up 1000 transparent huge pages using munmap()
had an execution time of 38,245us and 38,548us with and without the
patch respectively.  The performance gain is about 1%.

Signed-off-by: Waiman Long <Waiman.Long@hp.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Scott J Norton <scott.norton@hp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-06 18:01:16 -07:00
Joonsoo Kim
0de9d2ebe5 mm, CMA: clean-up log message
We don't need explicit 'CMA:' prefix, since we already define prefix
'cma:' in pr_fmt.  So remove it.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: Michal Nazarewicz <mina86@mina86.com>
Reviewed-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Alexander Graf <agraf@suse.de>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Gleb Natapov <gleb@kernel.org>
Acked-by: Marek Szyprowski <m.szyprowski@samsung.com>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-06 18:01:16 -07:00
Joonsoo Kim
c1f733aaaf mm, CMA: change cma_declare_contiguous() to obey coding convention
Conventionally, we put output param to the end of param list and put the
'base' ahead of 'size', but cma_declare_contiguous() doesn't look like
that, so change it.

Additionally, move down cma_areas reference code to the position where
it is really needed.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: Michal Nazarewicz <mina86@mina86.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Alexander Graf <agraf@suse.de>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Gleb Natapov <gleb@kernel.org>
Acked-by: Marek Szyprowski <m.szyprowski@samsung.com>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-06 18:01:16 -07:00
Joonsoo Kim
b7155e76a7 mm, CMA: clean-up CMA allocation error path
We can remove one call sites for clear_cma_bitmap() if we first call it
before checking error number.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Reviewed-by: Michal Nazarewicz <mina86@mina86.com>
Reviewed-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Alexander Graf <agraf@suse.de>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Gleb Natapov <gleb@kernel.org>
Acked-by: Marek Szyprowski <m.szyprowski@samsung.com>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-06 18:01:16 -07:00
Joonsoo Kim
fc95ca7284 PPC, KVM, CMA: use general CMA reserved area management framework
Now, we have general CMA reserved area management framework, so use it
for future maintainabilty.  There is no functional change.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: Michal Nazarewicz <mina86@mina86.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Tested-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Alexander Graf <agraf@suse.de>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Gleb Natapov <gleb@kernel.org>
Acked-by: Marek Szyprowski <m.szyprowski@samsung.com>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-06 18:01:16 -07:00
Joonsoo Kim
a254129e86 CMA: generalize CMA reserved area management functionality
Currently, there are two users on CMA functionality, one is the DMA
subsystem and the other is the KVM on powerpc.  They have their own code
to manage CMA reserved area even if they looks really similar.  From my
guess, it is caused by some needs on bitmap management.  KVM side wants
to maintain bitmap not for 1 page, but for more size.  Eventually it use
bitmap where one bit represents 64 pages.

When I implement CMA related patches, I should change those two places
to apply my change and it seem to be painful to me.  I want to change
this situation and reduce future code management overhead through this
patch.

This change could also help developer who want to use CMA in their new
feature development, since they can use CMA easily without copying &
pasting this reserved area management code.

In previous patches, we have prepared some features to generalize CMA
reserved area management and now it's time to do it.  This patch moves
core functions to mm/cma.c and change DMA APIs to use these functions.

There is no functional change in DMA APIs.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: Michal Nazarewicz <mina86@mina86.com>
Acked-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Alexander Graf <agraf@suse.de>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Gleb Natapov <gleb@kernel.org>
Acked-by: Marek Szyprowski <m.szyprowski@samsung.com>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-06 18:01:16 -07:00
Joonsoo Kim
e0bdb37d95 DMA, CMA: support arbitrary bitmap granularity
PPC KVM's CMA area management requires arbitrary bitmap granularity,
since they want to reserve very large memory and manage this region with
bitmap that one bit for several pages to reduce management overheads.
So support arbitrary bitmap granularity for following generalization.

[akpm@linux-foundation.org: s/1/1UL/]
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: Michal Nazarewicz <mina86@mina86.com>
Acked-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Alexander Graf <agraf@suse.de>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Gleb Natapov <gleb@kernel.org>
Acked-by: Marek Szyprowski <m.szyprowski@samsung.com>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-06 18:01:16 -07:00
Joonsoo Kim
a15bc0b89e DMA, CMA: support alignment constraint on CMA region
PPC KVM's CMA area management needs alignment constraint on CMA region.
So support it to prepare generalization of CMA area management
functionality.

Additionally, add some comments which tell us why alignment constraint
is needed on CMA region.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: Michal Nazarewicz <mina86@mina86.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Alexander Graf <agraf@suse.de>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Gleb Natapov <gleb@kernel.org>
Acked-by: Marek Szyprowski <m.szyprowski@samsung.com>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-06 18:01:16 -07:00
Joonsoo Kim
3162bbd7e6 DMA, CMA: separate core CMA management codes from DMA APIs
To prepare future generalization work on CMA area management code, we
need to separate core CMA management codes from DMA APIs.  We will
extend these core functions to cover requirements of PPC KVM's CMA area
management functionality in following patches.  This separation helps us
not to touch DMA APIs while extending core functions.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: Michal Nazarewicz <mina86@mina86.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Alexander Graf <agraf@suse.de>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Gleb Natapov <gleb@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Acked-by: Marek Szyprowski <m.szyprowski@samsung.com>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-06 18:01:16 -07:00
Fabian Frederick
bc7f84c0e6 mm/internal.h: use nth_page
Use nth_page instead of pfn_to_page(page_to_pfn

Signed-off-by: Fabian Frederick <fabf@skynet.be>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-06 18:01:16 -07:00
Michal Nazarewicz
7be12fc9f8 mm: page_alloc: simplify drain_zone_pages by using min()
Instead of open-coding getting minimal value of two, just use min macro.
That is why it is there for.  While changing the function also change
type of batch local variable to match type of per_cpu_pages::batch
(which is int).

Signed-off-by: Michal Nazarewicz <mina86@mina86.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>
2014-08-06 18:01:16 -07:00
Tang Chen
4f7c6b49c4 mem-hotplug: introduce MMOP_OFFLINE to replace the hard coding -1
In store_mem_state(), we have:

  ...
  334         else if (!strncmp(buf, "offline", min_t(int, count, 7)))
  335                 online_type = -1;
  ...
  355         case -1:
  356                 ret = device_offline(&mem->dev);
  357                 break;
  ...

Here, "offline" is hard coded as -1.

This patch does the following renaming:

 ONLINE_KEEP     ->  MMOP_ONLINE_KEEP
 ONLINE_KERNEL   ->  MMOP_ONLINE_KERNEL
 ONLINE_MOVABLE  ->  MMOP_ONLINE_MOVABLE

and introduces MMOP_OFFLINE = -1 to avoid hard coding.

Signed-off-by: Tang Chen <tangchen@cn.fujitsu.com>
Cc: Hu Tao <hutao@cn.fujitsu.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: Gu Zheng <guz.fnst@cn.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-06 18:01:16 -07:00
Tang Chen
1f6a6cc82e mem-hotplug: avoid illegal state prefixed with legal state when changing state of memory_block
We use the following command to online a memory_block:

    echo online|online_kernel|online_movable > /sys/devices/system/memory/memoryXXX/state

But, if we do the following:

    echo online_fhsjkghfkd > /sys/devices/system/memory/memoryXXX/state

the block will also be onlined.

This is because the following code in store_mem_state() does not compare
the whole string, but only the prefix of the string.

  store_mem_state()
  {
       ......
   328         if (!strncmp(buf, "online_kernel", min_t(int, count, 13)))

Here, only compare the first 13 letters of the string. If we give "online_kernelXXXXXX",
it will be recognized as online_kernel, which is incorrect.

   329                 online_type = ONLINE_KERNEL;
   330         else if (!strncmp(buf, "online_movable", min_t(int, count, 14)))

We have the same problem here,

   331                 online_type = ONLINE_MOVABLE;
   332         else if (!strncmp(buf, "online", min_t(int, count, 6)))

here,

(Here is more problematic.  If we give online_movalbe, which is a typo
of online_movable, it will be recognized as online without noticing the
author.)

   333                 online_type = ONLINE_KEEP;
   334         else if (!strncmp(buf, "offline", min_t(int, count, 7)))

and here.

   335                 online_type = -1;
   336         else {
   337                 ret = -EINVAL;
   338                 goto err;
   339         }
       ......
  }

This patch fixes this problem by using sysfs_streq() to compare the
whole string.

Signed-off-by: Tang Chen <tangchen@cn.fujitsu.com>
Reported-by: Hu Tao <hutao@cn.fujitsu.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: Gu Zheng <guz.fnst@cn.fujitsu.com>
Acked-by: Toshi Kani <toshi.kani@hp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-06 18:01:16 -07:00
Hugh Dickins
c0d73261f5 mm/memory.c: use entry = ACCESS_ONCE(*pte) in handle_pte_fault()
Use ACCESS_ONCE() in handle_pte_fault() when getting the entry or
orig_pte upon which all subsequent decisions and pte_same() tests will
be made.

I have no evidence that its lack is responsible for the mm/filemap.c:202
BUG_ON(page_mapped(page)) in __delete_from_page_cache() found by
trinity, and I am not optimistic that it will fix it.  But I have found
no other explanation, and ACCESS_ONCE() here will surely not hurt.

If gcc does re-access the pte before passing it down, then that would be
disastrous for correct page fault handling, and certainly could explain
the page_mapped() BUGs seen (concurrent fault causing page to be mapped
in a second time on top of itself: mapcount 2 for a single pte).

Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-06 18:01:15 -07:00
Joonsoo Kim
474750aba8 vmalloc: use rcu list iterator to reduce vmap_area_lock contention
Richard Yao reported a month ago that his system have a trouble with
vmap_area_lock contention during performance analysis by /proc/meminfo.
Andrew asked why his analysis checks /proc/meminfo stressfully, but he
didn't answer it.

  https://lkml.org/lkml/2014/4/10/416

Although I'm not sure that this is right usage or not, there is a
solution reducing vmap_area_lock contention with no side-effect.  That
is just to use rcu list iterator in get_vmalloc_info().

rcu can be used in this function because all RCU protocol is already
respected by writers, since Nick Piggin commit db64fe0225 ("mm:
rewrite vmap layer") back in linux-2.6.28

Specifically :
   insertions use list_add_rcu(),
   deletions use list_del_rcu() and kfree_rcu().

Note the rb tree is not used from rcu reader (it would not be safe),
only the vmap_area_list has full RCU protection.

Note that __purge_vmap_area_lazy() already uses this rcu protection.

        rcu_read_lock();
        list_for_each_entry_rcu(va, &vmap_area_list, list) {
                if (va->flags & VM_LAZY_FREE) {
                        if (va->va_start < *start)
                                *start = va->va_start;
                        if (va->va_end > *end)
                                *end = va->va_end;
                        nr += (va->va_end - va->va_start) >> PAGE_SHIFT;
                        list_add_tail(&va->purge_list, &valist);
                        va->flags |= VM_LAZY_FREEING;
                        va->flags &= ~VM_LAZY_FREE;
                }
        }
        rcu_read_unlock();

Peter:

: While rcu list traversal over the vmap_area_list is safe, this may
: arrive at different results than the spinlocked version. The rcu list
: traversal version will not be a 'snapshot' of a single, valid instant
: of the entire vmap_area_list, but rather a potential amalgam of
: different list states.

Joonsoo:

: Yes, you are right, but I don't think that we should be strict here.
: Meminfo is already not a 'snapshot' at specific time.  While we try to get
: certain stats, the other stats can change.  And, although we may arrive at
: different results than the spinlocked version, the difference would not be
: large and would not make serious side-effect.

[edumazet@google.com: add more commit description]
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Reported-by: Richard Yao <ryao@gentoo.org>
Acked-by: Eric Dumazet <edumazet@google.com>
Cc: Peter Hurley <peter@hurleysoftware.com>
Cc: Zhang Yanfei <zhangyanfei.yes@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Andi Kleen <andi@firstfloor.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-06 18:01:15 -07:00
Fabian Frederick
2cfb3665e8 include/linux/memblock.h: add __init to memblock_set_bottom_up()
memblock_set_bottom_up() is only called by __init
cmdline_parse_movable_node() and __init numa_init().

Signed-off-by: Fabian Frederick <fabf@skynet.be>
Reviewed-by: Tang Chen <tangchen@cn.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-06 18:01:15 -07:00
Andrew Morton
b95b4e1ed9 mm/page_alloc.c: unexport alloc_pages_exact_nid()
It is only called by mm/page_cgroup.c whcih cannot be modular.

Reported-by: David Rientjes <rientjes@google.com>
Cc: Fabian Frederick <fabf@skynet.be>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-06 18:01:15 -07:00
Fabian Frederick
e193181160 mm/page_alloc.c: add __meminit to alloc_pages_exact_nid()
alloc_pages_exact_nid() is only called by __meminit alloc_page_cgroup()

Signed-off-by: Fabian Frederick <fabf@skynet.be>
Cc: Mel Gorman <mgorman@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-06 18:01:15 -07:00
Fabian Frederick
f276540441 mm/memory_hotplug.c: add __meminit to grow_zone_span/grow_pgdat_span
grow_zone_span and grow_pgdat_span are only called by
__meminit __add_zone

Signed-off-by: Fabian Frederick <fabf@skynet.be>
Cc: Toshi Kani <toshi.kani@hp.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>
2014-08-06 18:01:15 -07:00