All of lore.kernel.org
 help / color / mirror / Atom feed
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?

  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 [RFC] mm, slab: reschedule cache_reap() on the same CPU 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

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=alpine.DEB.2.20.1804100907160.27333@nuc-kabylake \
    --to=cl@linux.com \
    --cc=iamjoonsoo.kim@lge.com \
    --cc=jiangshanlai@gmail.com \
    --cc=john.stultz@linaro.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=penberg@kernel.org \
    --cc=rientjes@google.com \
    --cc=sboyd@kernel.org \
    --cc=tglx@linutronix.de \
    --cc=tj@kernel.org \
    --cc=vbabka@suse.cz \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.