Re: [PATCH v2 1/5] sched, timer: Remove usages of ACCESS_ONCE in the scheduler

Steven Rostedt
2015-04-29T17:15:37Z

On Wed, 29 Apr 2015 13:05:55 -0400
Waiman Long <waiman.long@hp.com> wrote:

> > goto no_join;
> > @@ -2107,7 +2107,7 @@ void task_numa_fault(int last_cpupid, int mem_node, int pages, int flags)
> >
> > static void reset_ptenuma_scan(struct task_struct *p)
> > {
> > - ACCESS_ONCE(p->mm->numa_scan_seq)++;
> > + WRITE_ONCE(p->mm->numa_scan_seq, READ_ONCE(p->mm->numa_scan_seq) + 1);
> > p->mm->numa_scan_offset = 0;
> > }
> >
> >
>
> Generally, I am for replacing ACCESS_ONCE() with the more descriptive
> READ_ONCE() and WRITE_ONCE() except the above case where it makes the
> code harder to read without any real advantage.
>
> Other than that,
>
> Acked-by: Waiman Long <Waiman.Long@hp.com>
>

I agree, but I believe this code needs to be updated anyway. Making it
uglier may encourage that to happen.

-- Steve