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Subject: Re: rt14: strace ->  migrate_disable_atomic imbalance
From: Peter Zijlstra <peterz@infradead.org>
To: Mike Galbraith <efault@gmx.de>
Cc: linux-rt-users <linux-rt-users@vger.kernel.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        LKML <linux-kernel@vger.kernel.org>, Oleg Nesterov <oleg@redhat.com>,
        Miklos Szeredi <miklos@szeredi.hu>, mingo <mingo@redhat.com>
Date: Thu, 22 Sep 2011 10:38:50 +0200
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On Wed, 2011-09-21 at 20:50 +0200, Peter Zijlstra wrote:
> +static void wait_task_inactive_sched_out(struct preempt_notifier *n,
> +               struct task_struct *next)
> +{
> +       struct task_struct *p;
> +       struct wait_task_inactive_blocked *blocked = 
> +               container_of(n, struct wait_task_inactive_blocked, notifier);
> +
> +       if (current->on_rq) /* we're not inactive yet */
> +               return;
> +
> +       hlist_del(&n->link);
> +
> +       p = ACCESS_ONCE(blocked->waiter);
> +       blocked->waiter = NULL;
> +       wake_up_process(p);
> +} 

Trying a wakeup from there isn't going to actually ever work of-course..
Duh!