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

From: Tejun Heo
Date: Thu Oct 22 2015 - 10:09:56 EST


On Thu, Oct 22, 2015 at 08:39:11AM -0500, Christoph Lameter wrote:
> On Thu, 22 Oct 2015, Tetsuo Handa wrote:
>
> > The problem would be that the "struct task_struct" to execute vmstat_update
> > job does not exist, and will not be able to create one on demand because we
> > are stuck at __GFP_WAIT allocation. Therefore adding a dedicated kernel
> > thread for vmstat_update job would work. But ...
>
> Yuck. Can someone please get this major screwup out of the work queue
> subsystem? Tejun?

Hmmm? Just use a dedicated workqueue with WQ_MEM_RECLAIM. If
concurrency management is a problem and there's something live-locking
for that work item (really?), WQ_CPU_INTENSIVE escapes it. If this is
a common occurrence that it makes sense to give vmstat higher
priority, set WQ_HIGHPRI.

Thanks.

--
tejun
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