Re: [PATCH] mm,vmscan: Use accurate values for zone_reclaimable() checks

From: Michal Hocko
Date: Thu Oct 22 2015 - 11:49:29 EST


On Fri 23-10-15 00:37:03, Tejun Heo wrote:
> On Thu, Oct 22, 2015 at 05:35:59PM +0200, Michal Hocko wrote:
> > But that shouldn't happen because the allocation path does cond_resched
> > even when nothing is really reclaimable (e.g. wait_iff_congested from
> > __alloc_pages_slowpath).
>
> cond_resched() isn't enough. The work item should go !RUNNING, not
> just yielding.

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.
--
Michal Hocko
SUSE Labs
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