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Subject: Re: Bug in scheduler when using rt_mutex
From: Peter Zijlstra <peterz@infradead.org>
To: Yong Zhang <yong.zhang0@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>, samu.p.onkalo@nokia.com, mingo@elte.hu,
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Date: Fri, 21 Jan 2011 14:40:58 +0100
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On Fri, 2011-01-21 at 20:24 +0800, Yong Zhang wrote:
> > Index: linux-2.6/kernel/sched.c
> > ===================================================================
> > --- linux-2.6.orig/kernel/sched.c
> > +++ linux-2.6/kernel/sched.c
> > @@ -2624,6 +2624,8 @@ void sched_fork(struct task_struct *p, i
> >  
> >       if (!rt_prio(p->prio))
> >               p->sched_class = &fair_sched_class;
> > +     else
> > +             p->se.vruntime = 0;
> 
> This can be moved to __sched_fork() 

But we cannot do it unconditionally, we want to inherit the parent's
->vruntime when we're a fair task clone.