3.2.78-rc1 review patch. If anyone has any objections, please let me know.
------------------ From: Tetsuo Handa <[email protected]> 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 <[email protected]> Reported-by: Jan Stancek <[email protected]> Acked-by: Michal Hocko <[email protected]> Cc: Tejun Heo <[email protected]> Cc: Cristopher Lameter <[email protected]> Cc: Joonsoo Kim <[email protected]> Cc: Arkadiusz Miskiewicz <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]> Signed-off-by: Ben Hutchings <[email protected]> --- 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();
