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| author | Li RongQing <roy.qing.li@gmail.com> | 2016-05-27 14:27:43 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2016-05-27 14:49:37 -0700 |
| commit | cbedbac3e66121ddbac363776c23119f8eaeefda (patch) | |
| tree | 2705dfac84c6f79bef0415ca662eb98fe44d6a1d /mm/memcontrol.c | |
| parent | badbda53e505089062e194c614e6f23450bc98b2 (diff) | |
| download | lwn-cbedbac3e66121ddbac363776c23119f8eaeefda.tar.gz lwn-cbedbac3e66121ddbac363776c23119f8eaeefda.zip | |
mm/memcontrol.c: fix the margin computation in mem_cgroup_margin()
mem_cgroup_margin() might return (memory.limit - memory_count) when the
memsw.limit is in excess. This doesn't happen usually because we do not
allow excess on hard limits and (memory.limit <= memsw.limit), but
__GFP_NOFAIL charges can force the charge and cause the excess when no
memory is really swappable (swap is full or no anonymous memory is
left).
[mhocko@suse.com: rewrote changelog]
Link: http://lkml.kernel.org/r/20160525155122.GK20132@dhcp22.suse.cz
Link: http://lkml.kernel.org/r/1464068266-27736-1-git-send-email-roy.qing.li@gmail.com
Signed-off-by: Li RongQing <roy.qing.li@gmail.com>
Acked-by: Vladimir Davydov <vdavydov@virtuozzo.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/memcontrol.c')
| -rw-r--r-- | mm/memcontrol.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c index f6477a9dbe7a..485c688a7fa8 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -1108,6 +1108,8 @@ static unsigned long mem_cgroup_margin(struct mem_cgroup *memcg) limit = READ_ONCE(memcg->memsw.limit); if (count <= limit) margin = min(margin, limit - count); + else + margin = 0; } return margin; |