All of lore.kernel.org
 help / color / mirror / Atom feed
From: Tim Chen <tim.c.chen@linux.intel.com>
To: Linus Torvalds <torvalds@linux-foundation.org>,
	"Liang, Kan" <kan.liang@intel.com>
Cc: 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>,
	Christopher Lameter <cl@linux.com>,
	"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: Tue, 29 Aug 2017 09:13:29 -0700	[thread overview]
Message-ID: <bd2d09ea-47d1-c0a7-8d4d-604bb4bc28bc@linux.intel.com> (raw)
In-Reply-To: <CA+55aFwECeY-x=_du67qAxkta_0LeUw_BQA1kP337SBV3znN2Q@mail.gmail.com>

On 08/29/2017 09:01 AM, Linus Torvalds wrote:
> On Tue, Aug 29, 2017 at 5:57 AM, Liang, Kan <kan.liang@intel.com> wrote:
>>>
>>> Attached is an ALMOST COMPLETELY UNTESTED forward-port of those two
>>> patches, now without that nasty WQ_FLAG_ARRIVALS logic, because we now
>>> always put the new entries at the end of the waitqueue.
>>
>> The patches fix the long wait issue.
>>
>> Tested-by: Kan Liang <kan.liang@intel.com>
> 
> Ok. I'm not 100% comfortable applying them at rc7, so let me think
> about it. There's only one known load triggering this, and by "known"
> I mean "not really known" since we don't even know what the heck it
> does outside of intel and whoever your customer is.
> 
> So I suspect I'll apply the patches next merge window, and we can
> maybe mark them for stable if this actually ends up mattering.
> 
> Can you tell if the problem is actually hitting _production_ use or
> was some kind of benchmark stress-test?
> 
> 

It is affecting not a production use, but the customer's acceptance
test for their systems.  So I suspect it is a stress test.

Tim

WARNING: multiple messages have this Message-ID (diff)
From: Tim Chen <tim.c.chen@linux.intel.com>
To: Linus Torvalds <torvalds@linux-foundation.org>,
	"Liang, Kan" <kan.liang@intel.com>
Cc: 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>,
	Christopher Lameter <cl@linux.com>,
	"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: Tue, 29 Aug 2017 09:13:29 -0700	[thread overview]
Message-ID: <bd2d09ea-47d1-c0a7-8d4d-604bb4bc28bc@linux.intel.com> (raw)
In-Reply-To: <CA+55aFwECeY-x=_du67qAxkta_0LeUw_BQA1kP337SBV3znN2Q@mail.gmail.com>

On 08/29/2017 09:01 AM, Linus Torvalds wrote:
> On Tue, Aug 29, 2017 at 5:57 AM, Liang, Kan <kan.liang@intel.com> wrote:
>>>
>>> Attached is an ALMOST COMPLETELY UNTESTED forward-port of those two
>>> patches, now without that nasty WQ_FLAG_ARRIVALS logic, because we now
>>> always put the new entries at the end of the waitqueue.
>>
>> The patches fix the long wait issue.
>>
>> Tested-by: Kan Liang <kan.liang@intel.com>
> 
> Ok. I'm not 100% comfortable applying them at rc7, so let me think
> about it. There's only one known load triggering this, and by "known"
> I mean "not really known" since we don't even know what the heck it
> does outside of intel and whoever your customer is.
> 
> So I suspect I'll apply the patches next merge window, and we can
> maybe mark them for stable if this actually ends up mattering.
> 
> Can you tell if the problem is actually hitting _production_ use or
> was some kind of benchmark stress-test?
> 
> 

It is affecting not a production use, but the customer's acceptance
test for their systems.  So I suspect it is a stress test.

Tim

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

  reply	other threads:[~2017-08-29 16:13 UTC|newest]

Thread overview: 57+ 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 ` 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 16:13   ` Tim Chen
2017-08-25 19:58   ` Linus Torvalds
2017-08-25 19:58     ` Linus Torvalds
2017-08-25 22:19     ` Tim Chen
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  0:31             ` Linus Torvalds
2017-08-26  2:54             ` 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 21:40                   ` Linus Torvalds
2017-08-27 21:42                   ` Linus Torvalds
2017-08-27 21:42                     ` Linus Torvalds
2017-08-27 23:12                   ` Linus Torvalds
2017-08-27 23:12                     ` Linus Torvalds
2017-08-28  1:16                     ` Nicholas Piggin
2017-08-28  1:16                       ` Nicholas Piggin
2017-08-28  1:29                       ` Nicholas Piggin
2017-08-28  1:29                         ` Nicholas Piggin
2017-08-28  5:17                         ` Linus Torvalds
2017-08-28  5:17                           ` Linus Torvalds
2017-08-28  7:18                           ` Nicholas Piggin
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
2017-08-28 20:01                       ` Tim Chen
2017-08-29 12:57                     ` Liang, Kan
2017-08-29 16:01                       ` Linus Torvalds
2017-08-29 16:01                         ` Linus Torvalds
2017-08-29 16:13                         ` Tim Chen [this message]
2017-08-29 16:13                           ` Tim Chen
2017-08-29 16:24                           ` Linus Torvalds
2017-08-29 16:24                             ` Linus Torvalds
2017-08-29 16:57                             ` Tim Chen
2017-08-29 16:57                               ` Tim Chen
2017-09-14  2:12                             ` Tim Chen
2017-09-14  2:12                               ` Tim Chen
2017-09-14  2:27                               ` Linus Torvalds
2017-09-14  2:27                                 ` Linus Torvalds
2017-09-14 16:50                                 ` Tim Chen
2017-09-14 16:50                                   ` Tim Chen
2017-09-14 17:00                                   ` Linus Torvalds
2017-09-14 17:00                                     ` Linus Torvalds
2017-09-14 16:39                               ` Christopher Lameter
2017-08-29 16:17                     ` Tim Chen
2017-08-29 16:17                       ` Tim Chen
2017-08-29 16:22                       ` Linus Torvalds
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
2017-08-25 17:46   ` Christopher Lameter

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=bd2d09ea-47d1-c0a7-8d4d-604bb4bc28bc@linux.intel.com \
    --to=tim.c.chen@linux.intel.com \
    --cc=ak@linux.intel.com \
    --cc=akpm@linux-foundation.org \
    --cc=cl@linux.com \
    --cc=dave@stgolabs.net \
    --cc=ebiederm@xmission.com \
    --cc=hannes@cmpxchg.org \
    --cc=jack@suse.cz \
    --cc=kan.liang@intel.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=mgorman@techsingularity.net \
    --cc=mingo@elte.hu \
    --cc=peterz@infradead.org \
    --cc=torvalds@linux-foundation.org \
    /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.