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| author | Michal Hocko <mhocko@suse.com> | 2018-08-17 15:49:04 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2018-08-17 16:20:32 -0700 |
| commit | 9bfe5ded054b8e28a94c78580f233d6879a00146 (patch) | |
| tree | 0ad9d7261ab77ac01995e16abc1564c1d14bc872 | |
| parent | d834c5ab83febf9624ad3b16c3c348aa1e02014c (diff) | |
| download | linux-9bfe5ded054b8e28a94c78580f233d6879a00146.tar.bz2 | |
mm, oom: remove sleep from under oom_lock
Tetsuo has pointed out that since 27ae357fa82b ("mm, oom: fix concurrent
munlock and oom reaper unmap, v3") we have a strong synchronization
between the oom_killer and victim's exiting because both have to take
the oom_lock. Therefore the original heuristic to sleep for a short
time in out_of_memory doesn't serve the original purpose.
Moreover Tetsuo has noticed that the short sleep can be more harmful
than actually useful. Hammering the system with many processes can lead
to a starvation when the task holding the oom_lock can block for a long
time (minutes) and block any further progress because the oom_reaper
depends on the oom_lock as well.
Drop the short sleep from out_of_memory when we hold the lock. Keep the
sleep when the trylock fails to throttle the concurrent OOM paths a bit.
This should be solved in a more reasonable way (e.g. sleep proportional
to the time spent in the active reclaiming etc.) but this is much more
complex thing to achieve. This is a quick fixup to remove a stale code.
Link: http://lkml.kernel.org/r/20180709074706.30635-1-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | mm/oom_kill.c | 8 |
1 files changed, 1 insertions, 7 deletions
diff --git a/mm/oom_kill.c b/mm/oom_kill.c index 84081e77bc51..cd6520f7553d 100644 --- a/mm/oom_kill.c +++ b/mm/oom_kill.c @@ -1077,15 +1077,9 @@ bool out_of_memory(struct oom_control *oc) dump_header(oc, NULL); panic("Out of memory and no killable processes...\n"); } - if (oc->chosen && oc->chosen != (void *)-1UL) { + if (oc->chosen && oc->chosen != (void *)-1UL) oom_kill_process(oc, !is_memcg_oom(oc) ? "Out of memory" : "Memory cgroup out of memory"); - /* - * Give the killed process a good chance to exit before trying - * to allocate memory again. - */ - schedule_timeout_killable(1); - } return !!oc->chosen; } |