From: Tejun Heo <tj@kernel.org>
To: Hillf Danton <dhillf@gmail.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>,
Andrew Morton <akpm@linux-foundation.org>,
Ingo Molnar <mingo@elte.hu>, LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 2/3] stop_machine: dequeue work before signal completion
Date: Wed, 6 Feb 2013 10:47:49 -0800 [thread overview]
Message-ID: <20130206184749.GB2875@htj.dyndns.org> (raw)
In-Reply-To: <CAJd=RBBsMaXS5hA1OCX8Sp2y90Crktp6p4a7MSRZ3p6xq6RCmg@mail.gmail.com>
On Wed, Feb 06, 2013 at 08:38:43PM +0800, Hillf Danton wrote:
> As handled by the kernel thread, work is dequeued first for further actions.
Ditto as the previous patch.
> Signed-off-by: Hillf Danton <dhillf@gmail.com>
> ---
>
> --- a/kernel/stop_machine.c Wed Feb 6 19:57:12 2013
> +++ b/kernel/stop_machine.c Wed Feb 6 20:02:12 2013
> @@ -334,23 +334,24 @@ static int __cpuinit cpu_stop_cpu_callba
> #ifdef CONFIG_HOTPLUG_CPU
> case CPU_UP_CANCELED:
> case CPU_POST_DEAD:
> - {
> - struct cpu_stop_work *work;
> -
> sched_set_stop_task(cpu, NULL);
> /* kill the stopper */
> kthread_stop(stopper->thread);
> /* drain remaining works */
> spin_lock_irq(&stopper->lock);
> - list_for_each_entry(work, &stopper->works, list)
> + while (!list_empty(&stopper->works)) {
> + struct cpu_stop_work *work;
> + work = list_first_entry(&stopper->works,
> + struct cpu_stop_work, list);
> + list_del_init(&work->list);
> cpu_stop_signal_done(work->done, false, 0);
> + }
> stopper->enabled = false;
> spin_unlock_irq(&stopper->lock);
Why does this matter? It's inside spinlock. What's being made better
by this change?
--
tejun
next prev parent reply other threads:[~2013-02-06 18:47 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-02-06 12:38 [PATCH 2/3] stop_machine: dequeue work before signal completion Hillf Danton
2013-02-06 18:47 ` Tejun Heo [this message]
2013-02-07 2:21 ` Namhyung Kim
2013-02-07 2:29 ` Tejun Heo
2013-02-07 11:53 ` Hillf Danton
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