linux-kernel - Re: [PATCH v4] sched/fair: do not scan twice in detach

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <dac3339d-a721-442f-8638-6e4c493f35db@amperemail.onmicrosoft.com>
Date: Tue, 22 Jul 2025 11:16:17 +0800
From: Shijie Huang <shijie@...eremail.onmicrosoft.com>
To: Vincent Guittot <vincent.guittot@...aro.org>,
 Huang Shijie <shijie@...amperecomputing.com>
Cc: mingo@...hat.com, peterz@...radead.org, juri.lelli@...hat.com,
 vschneid@...hat.com, patches@...erecomputing.com, cl@...ux.com,
 Shubhang@...amperecomputing.com, dietmar.eggemann@....com,
 rostedt@...dmis.org, bsegall@...gle.com, mgorman@...e.de,
 linux-kernel@...r.kernel.org
Subject: Re: [PATCH v4] sched/fair: do not scan twice in detach_tasks()


On 2025/7/21 17:40, Vincent Guittot wrote:
> On Mon, 21 Jul 2025 at 04:40, Huang Shijie
> <shijie@...amperecomputing.com> wrote:
>> detach_tasks() uses struct lb_env.loop_max as an env.src_rq->cfs_tasks
>> iteration count limit. It is however set without the source RQ lock held,
>> and besides detach_tasks() can be re-invoked after releasing and
>> re-acquiring the RQ lock per LBF_NEED_BREAK.
>>
>> This means that env.loop_max and the actual length of env.src_rq->cfs_tasks
>> as observed within detach_tasks() can differ. This can cause some tasks to
> why not setting env.loop_max only once rq lock is taken in this case ?

Yes.  we do it in this way.


Thanks

Huang Shijie