Messages in this thread |  | | From | Namhyung Kim <> | Subject | Re: [PATCH 2/3] stop_machine: dequeue work before signal completion | Date | Thu, 07 Feb 2013 11:21:56 +0900 |
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Hi Tejun and Hillf,
On Wed, 6 Feb 2013 10:47:49 -0800, Tejun Heo wrote: > 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?
IIUC the work should be deleted from the list, otherwise it'd trigger BUG_ON when the cpu gets online again.
Thanks, Namhyung
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