Re: [PATCH v4 1/2] sched/rt: fix bad task migration for rt tasks

Steven Rostedt
2022-07-11T20:10:46Z

On Sat, 09 Jul 2022 05:32:25 +0800
Schspa Shi <schspa@gmail.com> wrote:

> >> +++ b/kernel/sched/rt.c
> >> @@ -1998,11 +1998,14 @@ static struct rq *find_lock_lowest_rq(struct task_struct *task, struct rq *rq)
> >> * the mean time, task could have
> >> * migrated already or had its affinity changed.
> >> * Also make sure that it wasn't scheduled on its rq.
> >> + * It is possible the task has running for a while,
> >
> > I don't understand the "running for a while" part. That doesn't make sense.
> >
>
> When I say "run for a while" I mean as long as the task has
> run capability, we should check the migrate disabled flag again.
>
> > The only way this can happen is that it was scheduled, set
> > "migrate_disabled" and then got preempted where it's no longer on the run
> > queue.
>
> Yes, it is the only case.

Can we then change the comment, as the "running for a while" is not clear
to what the issue is, and honestly, sounds misleading.

-- Steve