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Subject: Re: [PATCH 2/3] sched,fair: Fix local starvation
From: Mike Galbraith <mgalbraith@suse.de>
To: Wanpeng Li <kernellwp@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>, Ingo Molnar <mingo@kernel.org>,
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        Andrew Hunter <ahh@google.com>
Date: Sun, 22 May 2016 09:15:34 +0200
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On Sun, 2016-05-22 at 14:50 +0800, Wanpeng Li wrote:
> 2016-05-21 22:04 GMT+08:00 Mike Galbraith <mgalbraith@suse.de>:
> > 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.

	-Mike