Re: [PATCH v4] sched/fair: do not scan twice in detach_tasks()

[Shijie Huang]

On 2025/7/21 17:40, Vincent Guittot wrote:
> On Mon, 21 Jul 2025 at 04:40, Huang Shijie
> <shijie@xxxxxxxxxxxxxxxxxxxxxx> 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