Messages in this thread Patch in this message | | | From | Ben Hutchings <> | Date | Tue, 23 Feb 2016 21:42:03 +0000 | Subject | [PATCH 3.2 47/67] mm, vmstat: fix wrong WQ sleep when memory reclaim doesn't make any progress |
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3.2.78-rc1 review patch. If anyone has any objections, please let me know.
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From: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
commit 564e81a57f9788b1475127012e0fd44e9049e342 upstream.
Jan Stancek has reported that system occasionally hanging after "oom01" testcase from LTP triggers OOM. Guessing from a result that there is a kworker thread doing memory allocation and the values between "Node 0 Normal free:" and "Node 0 Normal:" differs when hanging, vmstat is not up-to-date for some reason.
According to commit 373ccbe59270 ("mm, vmstat: allow WQ concurrency to discover memory reclaim doesn't make any progress"), it meant to force the kworker thread to take a short sleep, but it by error used schedule_timeout(1). We missed that schedule_timeout() in state TASK_RUNNING doesn't do anything.
Fix it by using schedule_timeout_uninterruptible(1) which forces the kworker thread to take a short sleep in order to make sure that vmstat is up-to-date.
Fixes: 373ccbe59270 ("mm, vmstat: allow WQ concurrency to discover memory reclaim doesn't make any progress") Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Reported-by: Jan Stancek <jstancek@redhat.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Tejun Heo <tj@kernel.org> Cc: Cristopher Lameter <clameter@sgi.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Arkadiusz Miskiewicz <arekm@maven.pl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> --- mm/backing-dev.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/mm/backing-dev.c +++ b/mm/backing-dev.c @@ -879,7 +879,7 @@ long wait_iff_congested(struct zone *zon * here rather than calling cond_resched(). */ if (current->flags & PF_WQ_WORKER) - schedule_timeout(1); + schedule_timeout_uninterruptible(1); else cond_resched();
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