Re: [PATCH 2/2] mm: compaction: Minimise the time IRQs aredisabled while isolating pages for migration

From: Minchan Kim
Date: Mon Feb 28 2011 - 23:12:03 EST


On Tue, Mar 01, 2011 at 08:42:09AM +0900, KAMEZAWA Hiroyuki wrote:
> On Mon, 28 Feb 2011 10:18:27 +0000
> Mel Gorman <mel@xxxxxxxxx> wrote:
>
> > > BTW, can't we drop disable_irq() from all lru_lock related codes ?
> > >
> >
> > I don't think so - at least not right now. Some LRU operations such as LRU
> > pagevec draining are run from IPI which is running from an interrupt so
> > minimally spin_lock_irq is necessary.
> >
>
> pagevec draining is done by workqueue(schedule_on_each_cpu()).
> I think only racy case is just lru rotation after writeback.

put_page still need irq disable.


>
> Thanks,
> -Kame
>
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--
Kind regards,
Minchan Kim
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