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From: Dietmar Eggemann <dietmar.eggemann@arm.com>
To: Peter Zijlstra <peterz@infradead.org>,
	Vincent Guittot <vincent.guittot@linaro.org>
Cc: Zhang Qiao <zhangqiao22@huawei.com>,
	linux-kernel@vger.kernel.org, mingo@redhat.com,
	juri.lelli@redhat.com, rostedt@goodmis.org, bsegall@google.com,
	mgorman@suse.de, bristot@redhat.com, vschneid@redhat.com,
	rkagan@amazon.de
Subject: Re: [PATCH v2] sched/fair: sanitize vruntime of entity being migrated
Date: Tue, 14 Mar 2023 14:37:53 +0100	[thread overview]
Message-ID: <370e4908-eb8a-74d5-b771-8e657c3b6461@arm.com> (raw)
In-Reply-To: <14775160-8202-0bc6-a718-37c7ac1ed1db@arm.com>

On 14/03/2023 14:29, Dietmar Eggemann wrote:
> On 14/03/2023 13:07, Peter Zijlstra wrote:
>> On Tue, Mar 14, 2023 at 08:41:30AM +0100, Vincent Guittot wrote:

[...]

>> So when a task is not running for a long time (our case at hand), then
>> there's two cases:
>>
>>  - it wakes up locally and place_entity() gets to reset vruntime;
>>  - it wakes up remotely and migrate_task_rq_fair() can reset vruntime.
>>
>> So if we can rely on ENQUEUE_MIGRATED to differentiate between these
>> cases, when wouldn't something like this work?
> 
> I guess so. We would avoid rq_clock_task skews or to be forced to pass
> state that migrating se's vruntime is too old.

... just saw Vincent's reply ... I forgot the limitation that we can't
all rq_clock_task() in migrate_task_rq_fair() again.

[...]

  reply	other threads:[~2023-03-14 13:41 UTC|newest]

Thread overview: 59+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-03-06 13:24 Zhang Qiao
2023-03-06 13:53 ` Vincent Guittot
2023-03-07 10:26   ` Vincent Guittot
2023-03-07 11:05     ` Zhang Qiao
2023-03-07 13:41     ` Zhang Qiao
2023-03-08  8:01       ` Vincent Guittot
2023-03-08 12:55         ` Vincent Guittot
2023-03-09  8:37           ` Zhang Qiao
2023-03-09  9:09             ` Dietmar Eggemann
2023-03-09  9:30               ` Zhang Qiao
2023-03-09 10:48             ` Vincent Guittot
2023-03-09 14:23               ` Zhang Qiao
2023-03-07  2:16 ` kernel test robot
2023-03-07 12:45 ` Dietmar Eggemann
2023-03-07 14:06   ` Zhang Qiao
2023-03-09  9:43   ` Zhang Qiao
2023-03-08 14:33 ` Chen Yu
2023-03-09 13:05 ` Peter Zijlstra
2023-03-09 13:34   ` Vincent Guittot
2023-03-09 14:28     ` Peter Zijlstra
2023-03-09 14:36       ` Peter Zijlstra
2023-03-09 15:14         ` Vincent Guittot
2023-03-10 14:29           ` Vincent Guittot
2023-03-11  9:57             ` Zhang Qiao
2023-03-13 14:23               ` Vincent Guittot
2023-03-14 11:03                 ` Zhang Qiao
2023-03-14 13:26                   ` Vincent Guittot
2023-03-14 13:38                     ` Zhang Qiao
2023-03-14 13:39                       ` Vincent Guittot
2023-03-14 15:32                         ` Vincent Guittot
2023-03-15  9:16                           ` Zhang Qiao
2023-03-15 15:30                             ` Vincent Guittot
2023-03-13  9:06             ` Dietmar Eggemann
2023-03-13 18:17               ` Dietmar Eggemann
2023-03-14  7:41                 ` Vincent Guittot
2023-03-14 12:07                   ` Peter Zijlstra
2023-03-14 13:24                     ` Vincent Guittot
2023-03-14 17:16                       ` Peter Zijlstra
2023-03-15  7:18                         ` Vincent Guittot
2023-03-15  8:42                           ` Vincent Guittot
2023-03-15 10:15                             ` Dietmar Eggemann
2023-03-15 10:21                               ` Vincent Guittot
2023-03-15 13:35                                 ` Dietmar Eggemann
2023-03-15 15:32                                   ` Vincent Guittot
2023-03-14 13:29                     ` Dietmar Eggemann
2023-03-14 13:37                       ` Dietmar Eggemann [this message]
2023-03-17 16:08 Vincent Guittot
2023-03-18  7:45 ` Zhang Qiao
2023-03-20 12:29   ` Dietmar Eggemann
2023-03-20 13:26     ` Vincent Guittot
2023-03-21 10:02 ` Peter Zijlstra
2023-03-21 10:29   ` Dietmar Eggemann
2023-03-21 10:49     ` Peter Zijlstra
2023-03-21 11:12       ` Vincent Guittot
2023-03-21 11:13       ` Dietmar Eggemann
2023-03-21 12:26         ` Peter Zijlstra
2023-03-21 12:28 ` Peter Zijlstra
2023-03-21 12:38   ` Vincent Guittot
2023-03-24  4:05 ` Chen Yu

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