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From: Christopher Lameter <cl@linux.com>
To: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
	"Liang, Kan" <kan.liang@intel.com>,
	Mel Gorman <mgorman@techsingularity.net>,
	Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@elte.hu>, Andi Kleen <ak@linux.intel.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Johannes Weiner <hannes@cmpxchg.org>, Jan Kara <jack@suse.cz>,
	"Eric W . Biederman" <ebiederm@xmission.com>,
	Davidlohr Bueso <dave@stgolabs.net>,
	linux-mm <linux-mm@kvack.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 2/2 v2] sched/wait: Introduce lock breaker in wake_up_page_bit
Date: Thu, 14 Sep 2017 11:39:53 -0500 (CDT)	[thread overview]
Message-ID: <alpine.DEB.2.20.1709141138340.30688@nuc-kabylake> (raw)
In-Reply-To: <a9e74f64-dee6-dc23-128e-8ef8c7383d77@linux.intel.com>

On Wed, 13 Sep 2017, Tim Chen wrote:

> Here's what the customer think happened and is willing to tell us.
> They have a parent process that spawns off 10 children per core and
> kicked them to run. The child processes all access a common library.
> We have 384 cores so 3840 child processes running.  When migration occur on
> a page in the common library, the first child that access the page will
> page fault and lock the page, with the other children also page faulting
> quickly and pile up in the page wait list, till the first child is done.

I think we need some way to avoid migration in cases like this. This is
crazy. Page migration was not written to deal with something like this.

  parent reply	other threads:[~2017-09-14 16:39 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-08-25 16:13 [PATCH 1/2 v2] sched/wait: Break up long wake list walk Tim Chen
2017-08-25 16:13 ` [PATCH 2/2 v2] sched/wait: Introduce lock breaker in wake_up_page_bit Tim Chen
2017-08-25 19:58   ` Linus Torvalds
2017-08-25 22:19     ` Tim Chen
2017-08-25 22:51       ` Linus Torvalds
2017-08-25 23:03         ` Linus Torvalds
2017-08-26  0:31           ` Linus Torvalds
2017-08-26  2:54             ` Linus Torvalds
2017-08-26 18:15               ` Linus Torvalds
2017-08-27 21:40                 ` Linus Torvalds
2017-08-27 21:42                   ` Linus Torvalds
2017-08-27 23:12                   ` Linus Torvalds
2017-08-28  1:16                     ` Nicholas Piggin
2017-08-28  1:29                       ` Nicholas Piggin
2017-08-28  5:17                         ` Linus Torvalds
2017-08-28  7:18                           ` Nicholas Piggin
2017-08-28 14:51                 ` Liang, Kan
2017-08-28 16:48                   ` Linus Torvalds
2017-08-28 20:01                     ` Tim Chen
2017-08-29 12:57                     ` Liang, Kan
2017-08-29 16:01                       ` Linus Torvalds
2017-08-29 16:13                         ` Tim Chen
2017-08-29 16:24                           ` Linus Torvalds
2017-08-29 16:57                             ` Tim Chen
2017-09-14  2:12                             ` Tim Chen
2017-09-14  2:27                               ` Linus Torvalds
2017-09-14 16:50                                 ` Tim Chen
2017-09-14 17:00                                   ` Linus Torvalds
2017-09-14 16:39                               ` Christopher Lameter [this message]
2017-08-29 16:17                     ` Tim Chen
2017-08-29 16:22                       ` Linus Torvalds
2017-08-25 17:46 ` [PATCH 1/2 v2] sched/wait: Break up long wake list walk Christopher Lameter

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