Re: [PATCH 1/2] kthread: add barriers to set_kthread_struct() and to_kthread()

Tejun Heo
2017-03-16T15:38:52Z

On Thu, Mar 16, 2017 at 11:33:01AM -0400, Tejun Heo wrote:
> > And perhaps we should add another helper, say,
> >
> > #define lockless_assign_pointer(ptr, val) \
> > smp_store_release(&ptr, val)
> >
> > for set_kthread_struct() ? it can have more users.
> >
> > Not that I think you should change your patch, I am just asking.
>
> Ah yeah, that would look better. I vaguely remembered the new macro
> but couldn't quite remember it fully. :) Will update the patch.

Oops, as for adding lockless_assign_pointer(), wouldn't smp_wmb() be a
better match for smp_read_barrier_depends()? ISTR acquire/release
pairs being more expensive on some archs.

Thanks.

--
tejun