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| author |   Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> | 2018-04-05 16:23:35 -0700 |
|---|---|---|
| committer |   Linus Torvalds <torvalds@linux-foundation.org> | 2018-04-05 21:36:25 -0700 |
| commit | e830c63a621e20894a663351b968706bd0efbbd0 (patch) | |
| tree | db789c35c67d00d80d91698a11fb12ed64ab26dd /mm/vmscan.c | |
| parent | z3fold: limit use of stale list for allocation (diff) | |
| download | linux-dev-e830c63a621e20894a663351b968706bd0efbbd0.tar.xz linux-dev-e830c63a621e20894a663351b968706bd0efbbd0.zip | |
mm,vmscan: don't pretend forward progress upon shrinker_rwsem contention
Since we no longer use return value of shrink_slab() for normal reclaim,
the comment is no longer true. If some do_shrink_slab() call takes
unexpectedly long (root cause of stall is currently unknown) when
register_shrinker()/unregister_shrinker() is pending, trying to drop
caches via /proc/sys/vm/drop_caches could become infinite cond_resched()
loop if many mem_cgroup are defined. For safety, let's not pretend
forward progress.
Link: http://lkml.kernel.org/r/201802202229.GGF26507.LVFtMSOOHFJOQF@I-love.SAKURA.ne.jp
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Dave Chinner <dchinner@redhat.com>
Cc: Glauber Costa <glommer@gmail.com>
Cc: Mel Gorman <mgorman@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/vmscan.c')
| -rw-r--r-- | mm/vmscan.c | 10 |
1 files changed, 1 insertions, 9 deletions
diff --git a/mm/vmscan.c b/mm/vmscan.c index ca566640c448..976be140a8ce 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -442,16 +442,8 @@ static unsigned long shrink_slab(gfp_t gfp_mask, int nid, if (memcg && (!memcg_kmem_enabled() || !mem_cgroup_online(memcg))) return 0; - if (!down_read_trylock(&shrinker_rwsem)) { - /* - * If we would return 0, our callers would understand that we - * have nothing else to shrink and give up trying. By returning - * 1 we keep it going and assume we'll be able to shrink next - * time. - */ - freed = 1; + if (!down_read_trylock(&shrinker_rwsem)) goto out; - } list_for_each_entry(shrinker, &shrinker_list, list) { struct shrink_control sc = { |