| From 564e81a57f9788b1475127012e0fd44e9049e342 Mon Sep 17 00:00:00 2001 |
| From: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp> |
| Date: Fri, 5 Feb 2016 15:36:30 -0800 |
| Subject: 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 <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: Zefan Li <lizefan@huawei.com> |
| --- |
| mm/backing-dev.c | 2 +- |
| 1 file changed, 1 insertion(+), 1 deletion(-) |
| |
| --- a/mm/backing-dev.c |
| +++ b/mm/backing-dev.c |
| @@ -875,7 +875,7 @@ 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(); |
| |
