Re: [PATCH 2/3] sched,fair: Fix local starvation

From: Wanpeng Li
Date: Sun May 22 2016 - 03:27:52 EST


2016-05-22 15:15 GMT+08:00 Mike Galbraith <mgalbraith@xxxxxxx>:
> On Sun, 2016-05-22 at 14:50 +0800, Wanpeng Li wrote:
>> 2016-05-21 22:04 GMT+08:00 Mike Galbraith <mgalbraith@xxxxxxx>:
>> > On Tue, 2016-05-10 at 19:43 +0200, Peter Zijlstra wrote:
>> >
>> > (Evolution authors must either not do patch review, or use some other
>> > mailer. Squint hard, this crud really is your patch;)
>> >
>> > > --- a/kernel/sched/core.c
>> > > +++ b/kernel/sched/core.c
>> > >
>> > > @@ -1762,7 +1770,11 @@ void sched_ttwu_pending(void)
>> > > > > while (llist) {
>> > > > > > p = llist_entry(llist, struct task_struct, wake_entry);
>> > > > > > llist = llist_next(llist);
>> > > -> > > ttwu_do_activate(rq, p, 0, cookie);
>> > > +> > > /*
>> > > +> > > * See ttwu_queue(); we only call ttwu_queue_remote() when
>> > > +> > > * its a x-cpu wakeup.
>> > > +> > > */
>> > > +> > > ttwu_do_activate(rq, p, WF_MIGRATED, cookie);
>> >
>> > Wakees that were not migrated/normalized eat an unwanted min_vruntime,
>>
>> Why there were wakees queued by twu_queue_remote() not migrated?
>
> Queuing to a remote cache domain implies x-cpu wakeup, but does not
> imply migration.

What's the meaning of 'x-cpu wakeup'? ;-)

Regards,
Wanpeng Li