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Date: Thu, 22 Oct 2015 17:49:22 +0200
From: Michal Hocko <mhocko@kernel.org>
To: Tejun Heo <htejun@gmail.com>
Cc: Christoph Lameter <cl@linux.com>,
        Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>, linux-mm@kvack.org,
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        vdavydov@parallels.com, skozina@redhat.com, mgorman@suse.de,
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Subject: Re: [PATCH] mm,vmscan: Use accurate values for zone_reclaimable()
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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