From: Tejun Heo <tj@kernel.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: cmetcalf@ezchip.com, Frederic Weisbecker <fweisbec@gmail.com>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
"Rafael J. Wysocki" <rafael.j.wysocki@intel.com>,
Martin Schwidefsky <schwidefsky@de.ibm.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] workqueue: avoid nohz_full cores
Date: Wed, 1 Apr 2015 11:46:37 -0400 [thread overview]
Message-ID: <20150401154637.GN9974@htj.duckdns.org> (raw)
In-Reply-To: <20150401075607.GW27490@worktop.programming.kicks-ass.net>
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
next prev parent reply other threads:[~2015-04-01 15:46 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-03-31 19:25 [PATCH] workqueue: avoid nohz_full cores cmetcalf
2015-03-31 19:37 ` Tejun Heo
2015-04-01 7:56 ` Peter Zijlstra
2015-04-01 15:46 ` Tejun Heo [this message]
2015-03-31 20:58 ` Frederic Weisbecker
2015-03-31 21:06 ` Tejun Heo
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