Re: [PATCH 0/1] kthread: don't abuse kthread_create_on_cpu() in __kthread_create_worker()

From: Petr Mladek
Date: Mon Nov 14 2016 - 06:10:05 EST


On Thu 2016-11-10 18:19:58, Oleg Nesterov wrote:
> On 11/09, Oleg Nesterov wrote:
> >
> > Yes, agreed. Again, I'll write another email. Perhaps we should even keep
> > park/unpark exported and change them to avoid the races with exit/itself,
> > I dunno.
> >
> > My real point was, imo the KTHREAD_IS_PER_CPU/__kthread_bind(kthread->cpu)
> > logic in kthread_unpark() should be private to smpboot.c/cpu.c.
> >
> > I'll send another patch tomorrow. kthread_create_worker_on_cpu() ab-uses
> > this logic too for no reason, but this is trivial.
>
> After this change we are almost ready to kill kthread->cpu and KTHREAD_IS_PER_CPU.
> (but the change itself doesn't depend on the previous patches).
>
> Petr, why do we need kthread_create_worker_on_cpu() ? It has no users and
> I can not imagine any "real" use-case for it. Perhaps it can be removed?

kthread_create_worker_on_cpu() is going to have some users. For
example, patches for intel_powerclamp are already flying around,
see
https://lkml.kernel.org/r/1476707572-32215-3-git-send-email-pmladek@xxxxxxxx

Best Regards,
Petr