Re: [PATCH] sched: flush plug in schedule_preempt_disabled() to prevent deadlock

[Peter Zijlstra]

On Tue, May 12, 2026 at 11:45:14PM +0800, Ming Lei wrote:

> > io_schedule()
> >   token = io_schedule_prepare()
> >     blk_flush_plug(current->plug, true);
> >   schedule()
> >     if (!task_is_running(tsk))
> >       sched_submit_work()
> >         blk_flush_plug(tsk->plug, true);
> > 
> > Why isn't the one in sched_submit_work() sufficient? This thing either
> > needs a comment justifying its existence, or get removed.

> If io_schedule_prepare() can be called in every iowait context, looks
> blk_flush_plug() from sched_submit_work() may be removed.

No, the other way around. I don't see the point of having the one in
io_schedule_prepare(), since we'll hit the one in sched_submit_work().