Re: [PATCH] workqueue: avoid nohz_full cores

From: Tejun Heo
Date: Wed Apr 01 2015 - 11:46:55 EST


On Wed, Apr 01, 2015 at 09:56:07AM +0200, Peter Zijlstra wrote:
> > The problem with this is that workqueue currently doesn't distinguish
> > why work items are queued on per-cpu workqueues. It can't tell
> > whether being bound to local CPU is for correctness or optimization
> > and thus can't break local execution guarantee for anybody. We need
> > to hunt down all the ones which depend on local execution and annotate
> > them with explicit queue_work_on() before being able to do this.
>
> This is moot on unbound workqueues, they can run wherever so it can
> never be a correctness thing, right?

The posted patch applies to both unbound and per-cpu workqueues.
There's a more comprehensive patchset currently being worked on by Lai
for unbound workqueues.

Thanks.

--
tejun
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