On Fri, Dec 11, 2020 at 02:25:42PM +0800, Hillf Danton wrote:
> On Tue, 8 Dec 2020 15:35:00 +0000 Mel Gorman wrote:
> > @@ -6277,17 +6277,13 @@ static int select_idle_sibling(struct task_struct
> > *p, int prev, int target)
> >
> > /* Check a recently used CPU as a potential idle candidate: */
> > recent_used_cpu = p->recent_used_cpu;
> > + p->recent_used_cpu = prev;
> > if (recent_used_cpu != prev &&
> > recent_used_cpu != target &&
> > cpus_share_cache(recent_used_cpu, target) &&
> > (available_idle_cpu(recent_used_cpu) ||
> > sched_idle_cpu(recent_used_cpu)) &&
> > cpumask_test_cpu(p->recent_used_cpu, p->cpus_ptr) &&
>
> Typo? Fix it in spin if so.
>
What typo?
> > asym_fits_capacity(task_util, recent_used_cpu)) {
> > - /*
> > - * Replace recent_used_cpu with prev as it is a potential
> > - * candidate for the next wake:
> > - */
> > - p->recent_used_cpu = prev;
> > return recent_used_cpu;
>
> I prefer to update the recent CPU after llc check.
>
That would prevent recent_used_cpu leaving the LLC the task first
started on.
--
Mel Gorman
SUSE Labs
