Re: [PATCH v3] stop_machine: Make migration_cpu_stop() does useful works for CONFIG_PREEMPT_NONE

[Oleg Nesterov]

On 09/13, Peter Zijlstra wrote:
>
> On Tue, Sep 13, 2016 at 06:14:27PM +0200, Oleg Nesterov wrote:
>
> > Hmm. And  preempt_enable_no_resched_notrace() under TASK_DEAD in
> > __schedule() should be removed it seems, do_exit() can call __schedule()
> > directly.
>
> something like so?

Yes, exactly.

But I think that raw_spin_unlock_wait(&tsk->pi_lock) and its huge
comment should be moved into the new helper too, this connects to
set_current_state(TASK_DEAD).

Oleg.