Re: [PATCH v3 3/9] memory-hotplug: flush the work for the node whenthe node is offlined

[KOSAKI Motohiro]

On Fri, Oct 19, 2012 at 2:46 AM,  <wency@xxxxxxxxxxxxxx> wrote:
> From: Yasuaki Ishimatsu <isimatu.yasuaki@xxxxxxxxxxxxxx>
>
> If the node is onlined after it is offlined, we will clear the memory
> to store the node's information. This structure contains struct work,
> so we should flush work before the work's information is cleared.

This explanation is incorrect. Even if you don't call memset(), you should
call flush_work() at offline event. Because of, after offlinining, we
shouldn't touch any node data. Alive workqueue violate this principle.

And, hmmm... Wait. Usually workqueue shutdowning has two phase. 1)
inhibit enqueue new work 2) flush work. Otherwise other cpus may
enqueue new work after flush_work(). Where is (1)?
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