From: Christopher Lameter <cl@linux.com>
To: Vlastimil Babka <vbabka@suse.cz>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Joonsoo Kim <iamjoonsoo.kim@lge.com>,
David Rientjes <rientjes@google.com>,
Pekka Enberg <penberg@kernel.org>, Tejun Heo <tj@kernel.org>,
Lai Jiangshan <jiangshanlai@gmail.com>,
John Stultz <john.stultz@linaro.org>,
Thomas Gleixner <tglx@linutronix.de>,
Stephen Boyd <sboyd@kernel.org>
Subject: Re: [RFC] mm, slab: reschedule cache_reap() on the same CPU
Date: Tue, 10 Apr 2018 09:12:08 -0500 (CDT) [thread overview]
Message-ID: <alpine.DEB.2.20.1804100907160.27333@nuc-kabylake> (raw)
In-Reply-To: <20180410081531.18053-1-vbabka@suse.cz>
On Tue, 10 Apr 2018, Vlastimil Babka wrote:
> cache_reap() is initially scheduled in start_cpu_timer() via
> schedule_delayed_work_on(). But then the next iterations are scheduled via
> schedule_delayed_work(), thus using WORK_CPU_UNBOUND.
That is a bug.. cache_reap must run on the same cpu since it deals with
the per cpu queues of the current cpu. Scheduled_delayed_work() used to
guarantee running on teh same cpu.
> This patch makes sure schedule_delayed_work_on() is used with the proper cpu
> when scheduling the next iteration. The cpu is stored with delayed_work on a
> new slab_reap_work_struct super-structure.
The current cpu is readily available via smp_processor_id(). Why a
super structure?
> @@ -4074,7 +4086,8 @@ static void cache_reap(struct work_struct *w)
> next_reap_node();
> out:
> /* Set up the next iteration */
> - schedule_delayed_work(work, round_jiffies_relative(REAPTIMEOUT_AC));
> + schedule_delayed_work_on(reap_work->cpu, work,
> + round_jiffies_relative(REAPTIMEOUT_AC));
schedule_delayed_work_on(smp_processor_id(), work, round_jiffies_relative(REAPTIMEOUT_AC));
instead all of the other changes?
next prev parent reply other threads:[~2018-04-10 14:12 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-04-10 8:15 Vlastimil Babka
2018-04-10 14:12 ` Christopher Lameter [this message]
2018-04-10 14:17 ` Tejun Heo
2018-04-10 19:40 ` Vlastimil Babka
2018-04-10 19:53 ` Tejun Heo
2018-04-10 20:13 ` Vlastimil Babka
2018-04-10 20:23 ` Tejun Heo
2018-04-11 7:00 ` [PATCH] " Vlastimil Babka
2018-04-11 10:53 ` Pekka Enberg
2018-04-11 13:41 ` Christopher Lameter
2018-04-12 0:47 ` Minchan Kim
2018-04-13 8:44 ` Vlastimil Babka
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