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From: Chengming Zhou <zhouchengming@bytedance.com>
To: Dietmar Eggemann <dietmar.eggemann@arm.com>,
	mingo@redhat.com, peterz@infradead.org,
	vincent.guittot@linaro.org, rostedt@goodmis.org,
	bsegall@google.com, vschneid@redhat.com
Cc: linux-kernel@vger.kernel.org
Subject: Re: [External] Re: [PATCH v2 04/10] sched/fair: remove redundant cpu_cgrp_subsys->fork()
Date: Thu, 14 Jul 2022 21:06:04 +0800	[thread overview]
Message-ID: <00d2373c-4b80-64a7-740c-dae87a565fe3@bytedance.com> (raw)
In-Reply-To: <fa74892c-2956-6ddf-e022-398b89056e5a@arm.com>

On 2022/7/14 20:31, Dietmar Eggemann wrote:
> On 13/07/2022 06:04, Chengming Zhou wrote:
>> We use cpu_cgrp_subsys->fork() to set task group for the new fair task
>> in cgroup_post_fork().
>>
>> Since commit b1e8206582f9 ("sched: Fix yet more sched_fork() races")
>> has already set task group for the new fair task in sched_cgroup_fork(),
>> so cpu_cgrp_subsys->fork() can be removed.
>>
>>   cgroup_can_fork()	--> pin parent's sched_task_group
>>   sched_cgroup_fork()
> 
> Don't we set the task group (`p->sched_task_group = tg`) now directly in
> sched_cgroup_fork() and not in __set_task_cpu()?

Correct, it's my fault, what I want to say is "__set_task_cpu() --> set_task_rq()".
I will fix it next version.

> 
>>     __set_task_cpu	--> set task group
>>   cgroup_post_fork()
>>     ss->fork() := cpu_cgroup_fork()	--> set again
> 
> nit pick:
> 
> cpu_cgroup_fork() -> sched_change_group(..., TASK_SET_GROUP)

Ok, will add this.

Thanks.

> 
>> After this patch's change, task_change_group_fair() only need to
>> care about task cgroup migration, make the code much simplier.
>>
>> Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
>> Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org>
> 
> LGTM too.
> 
> Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
> 
> [...]

  reply	other threads:[~2022-07-14 13:06 UTC|newest]

Thread overview: 37+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-07-13  4:04 [PATCH v2 00/10] sched: task load tracking optimization and cleanup Chengming Zhou
2022-07-13  4:04 ` [PATCH v2 01/10] sched/fair: combine detach into dequeue when migrating task Chengming Zhou
2022-07-13  4:04 ` [PATCH v2 02/10] sched/fair: update comments in enqueue/dequeue_entity() Chengming Zhou
2022-07-13  4:04 ` [PATCH v2 03/10] sched/fair: maintain task se depth in set_task_rq() Chengming Zhou
2022-07-14 12:30   ` Dietmar Eggemann
2022-07-14 13:03     ` [External] " Chengming Zhou
2022-07-18  7:16   ` Vincent Guittot
2022-07-13  4:04 ` [PATCH v2 04/10] sched/fair: remove redundant cpu_cgrp_subsys->fork() Chengming Zhou
2022-07-14 12:31   ` Dietmar Eggemann
2022-07-14 13:06     ` Chengming Zhou [this message]
2022-07-13  4:04 ` [PATCH v2 05/10] sched/fair: reset sched_avg last_update_time before set_task_rq() Chengming Zhou
2022-07-14 12:31   ` Dietmar Eggemann
2022-07-19  8:49   ` Vincent Guittot
2022-07-13  4:04 ` [PATCH v2 06/10] sched/fair: delete superfluous SKIP_AGE_LOAD Chengming Zhou
2022-07-14 12:33   ` Dietmar Eggemann
2022-07-14 13:24     ` [External] " Chengming Zhou
2022-07-13  4:04 ` [PATCH v2 07/10] sched/fair: use update_load_avg() to attach/detach entity load_avg Chengming Zhou
2022-07-15 11:18   ` Dietmar Eggemann
2022-07-15 16:21     ` [External] " Chengming Zhou
2022-07-19 10:29       ` Vincent Guittot
2022-07-20 13:40         ` Chengming Zhou
2022-07-20 15:34           ` Vincent Guittot
2022-07-21 13:56             ` Chengming Zhou
2022-07-21 14:13               ` Vincent Guittot
2022-07-19 15:02       ` Dietmar Eggemann
2022-07-20 13:43         ` Chengming Zhou
2022-07-13  4:04 ` [PATCH v2 08/10] sched/fair: fix load tracking for new forked !fair task Chengming Zhou
2022-07-19 12:35   ` Vincent Guittot
2022-07-20 13:48     ` [External] " Chengming Zhou
2022-07-13  4:04 ` [PATCH v2 09/10] sched/fair: stop load tracking when task switched_from_fair() Chengming Zhou
2022-07-14 12:33   ` Dietmar Eggemann
2022-07-14 13:43     ` [External] " Chengming Zhou
2022-07-15 11:15       ` Dietmar Eggemann
2022-07-15 16:35         ` Chengming Zhou
2022-07-19 13:20   ` Vincent Guittot
2022-07-27 10:55     ` Chengming Zhou
2022-07-13  4:04 ` [PATCH v2 10/10] sched/fair: delete superfluous set_task_rq_fair() Chengming Zhou

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