From: Peter Zijlstra <peterz@infradead.org>
To: Mike Galbraith <efault@gmx.de>
Cc: Ingo Molnar <mingo@elte.hu>, LKML <linux-kernel@vger.kernel.org>
Subject: Re: [patch] sched: fix b5d9d734 blunder in task_new_fair()
Date: Thu, 26 Nov 2009 17:26:25 +0100 [thread overview]
Message-ID: <1259252785.31676.216.camel@laptop> (raw)
In-Reply-To: <1258891664.14325.30.camel@marge.simson.net>
On Sun, 2009-11-22 at 13:07 +0100, Mike Galbraith wrote:
> @@ -2589,16 +2588,10 @@ void sched_fork(struct task_struct *p, i
> */
> p->prio = current->normal_prio;
>
> - if (!rt_prio(p->prio))
> + if (!task_has_rt_policy(p))
> p->sched_class = &fair_sched_class;
>
> -#ifdef CONFIG_SMP
> - cpu = p->sched_class->select_task_rq(p, SD_BALANCE_FORK, 0);
> -#endif
> - local_irq_save(flags);
> - update_rq_clock(cpu_rq(cpu));
> - set_task_cpu(p, cpu);
> - local_irq_restore(flags);
> + __set_task_cpu(p, cpu);
OK, so I figured out why it was in sched_fork() and not in
wake_up_new_task().
It is because in sched_fork() the new task isn't in the tasklist yet and
can therefore not race with any other migration logic.
next prev parent reply other threads:[~2009-11-26 16:26 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-11-22 12:07 [patch] sched: fix b5d9d734 blunder in task_new_fair() Mike Galbraith
2009-11-24 13:51 ` Peter Zijlstra
2009-11-24 17:07 ` Mike Galbraith
2009-11-24 17:35 ` Peter Zijlstra
2009-11-24 17:54 ` Peter Zijlstra
2009-11-24 18:21 ` Mike Galbraith
2009-11-24 18:27 ` Peter Zijlstra
2009-11-24 18:36 ` Mike Galbraith
2009-11-25 6:57 ` Mike Galbraith
2009-11-25 9:51 ` Peter Zijlstra
2009-11-25 13:09 ` Mike Galbraith
2009-11-26 16:26 ` Peter Zijlstra [this message]
2009-11-27 8:45 ` Mike Galbraith
2009-11-27 8:57 ` Mike Galbraith
2009-11-27 11:55 ` Mike Galbraith
2009-11-27 12:21 ` Peter Zijlstra
2009-11-27 12:38 ` Peter Zijlstra
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