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From: Christoph Lameter <cl@linux.com>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Tejun Heo <tj@kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Michal Hocko <mhocko@suse.cz>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Lai Jiangshan <jiangshanlai@gmail.com>, Shaohua Li <shli@fb.com>,
	linux-mm <linux-mm@kvack.org>
Subject: Re: [GIT PULL] workqueue fixes for v4.3-rc5
Date: Wed, 14 Oct 2015 12:57:31 -0500 (CDT)	[thread overview]
Message-ID: <alpine.DEB.2.20.1510141253570.13238@east.gentwo.org> (raw)
In-Reply-To: <CA+55aFzhHF0KMFvebegBnwHqXekfRRd-qczCtJXKpf3XvOCW=A@mail.gmail.com>

On Wed, 14 Oct 2015, Linus Torvalds wrote:

> I don't think it's normally a problem. But mm/vmstat.c clearly *is*
> confused, and uses both "schedule_delayed_work_on()" and
> "schedule_delayed_work()" for the same work.

Well yes the schedule_delayed_work_on() call is from another cpu and the
schedule_delayed_work() from the same. No confusion there.

vmstat_update() is run from the cpu where the diffs have to be updated and
if it needs to reschedule itself it relies on schedule_delayed_work() to
stay on the same cpu.

The vmstat_shepherd needs to start work items on remote cpus and therefore
uses xx_work_on().

And yes this relies on work items being executed on the same cpu unless
the queue is decleared to be UNBOUND which is not the case here.

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  reply	other threads:[~2015-10-14 17:57 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20151013214952.GB23106@mtj.duckdns.org>
2015-10-14 16:30 ` Linus Torvalds
2015-10-14 16:57   ` Tejun Heo
2015-10-14 17:36     ` Linus Torvalds
2015-10-14 17:57       ` Christoph Lameter [this message]
2015-10-14 18:37         ` Linus Torvalds
2015-10-14 18:58           ` Christoph Lameter
2015-10-14 19:01           ` Linus Torvalds
2015-10-14 19:02       ` Tejun Heo
2015-10-14 19:16         ` Linus Torvalds
2015-10-14 19:38           ` Tejun Heo
2015-10-14 20:10             ` Linus Torvalds
2015-10-14 20:24               ` Tejun Heo
2015-10-19  3:51                 ` Mike Galbraith
2015-10-16 19:51               ` [PATCH] vmstat_update: ensure work remains on the same core Chris Metcalf
2015-10-16 19:54                 ` Linus Torvalds
2015-10-14 18:03   ` [GIT PULL] workqueue fixes for v4.3-rc5 Christoph Lameter
2015-10-14 18:40     ` Linus Torvalds
2015-10-14 18:59       ` Christoph Lameter
2015-10-14 19:10         ` Linus Torvalds

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