Messages in this thread Patch in this message | | | Subject | Re: [PATCH] mm,vmscan: Use accurate values for zone_reclaimable()checks | From | Tetsuo Handa <> | Date | Fri, 23 Oct 2015 06:42:43 +0900 |
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Tejun Heo wrote: > On Thu, Oct 22, 2015 at 05:49:22PM +0200, Michal Hocko wrote: > > I am confused. What makes rescuer to not run? Nothing seems to be > > hogging CPUs, we are just out of workers which are loopin in the > > allocator but that is preemptible context. > > It's concurrency management. Workqueue thinks that the pool is making > positive forward progress and doesn't schedule anything else for > execution while that work item is burning cpu cycles.
Then, isn't below change easier to backport which will also alleviate needlessly burning CPU cycles?
--- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -3385,6 +3385,7 @@ retry: ((gfp_mask & __GFP_REPEAT) && pages_reclaimed < (1 << order))) { /* Wait for some write requests to complete then retry */ wait_iff_congested(ac->preferred_zone, BLK_RW_ASYNC, HZ/50); + schedule_timeout_uninterruptible(1); goto retry; }
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