From: Tetsuo Handa Date: Fri, 5 Feb 2016 23:36:30 +0000 (-0800) Subject: mm, vmstat: fix wrong WQ sleep when memory reclaim doesn't make any progress X-Git-Tag: v3.2.78~21 X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?p=pandora-kernel.git;a=commitdiff_plain;h=939f1e0d840ff8145db78ded0673b3207f49b959;hp=075ee9fb5e1ebfa5defc64746dfcbba28cf0ed5f mm, vmstat: fix wrong WQ sleep when memory reclaim doesn't make any progress 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 Reported-by: Jan Stancek Acked-by: Michal Hocko Cc: Tejun Heo Cc: Cristopher Lameter Cc: Joonsoo Kim Cc: Arkadiusz Miskiewicz Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Ben Hutchings --- diff --git a/mm/backing-dev.c b/mm/backing-dev.c index 17f54030263d..845e58b35507 100644 --- a/mm/backing-dev.c +++ b/mm/backing-dev.c @@ -879,7 +879,7 @@ long wait_iff_congested(struct zone *zone, int sync, long timeout) * here rather than calling cond_resched(). */ if (current->flags & PF_WQ_WORKER) - schedule_timeout(1); + schedule_timeout_uninterruptible(1); else cond_resched();