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From: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
To: Nick Piggin <npiggin@suse.de>
Subject: Re: [RFC][PATCH] lru_add_drain_all() don't use schedule_on_each_cpu()
Cc: kosaki.motohiro@jp.fujitsu.com, Heiko Carstens <heiko.carstens@de.ibm.com>,
       linux-kernel@vger.kernel.org, Hugh Dickins <hugh@veritas.com>,
       Andrew Morton <akpm@linux-foundation.org>,
       Linus Torvalds <torvalds@linux-foundation.org>,
       Rik van Riel <riel@redhat.com>,
       Lee Schermerhorn <lee.schermerhorn@hp.com>, linux-mm@kvack.org,
       Christoph Lameter <cl@linux-foundation.org>
In-Reply-To: <20081024053402.GA11725@wotan.suse.de>
References: <20081024140723.9C49.KOSAKI.MOTOHIRO@jp.fujitsu.com> <20081024053402.GA11725@wotan.suse.de>
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Date: Fri, 24 Oct 2008 14:51:32 +0900 (JST)
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> On Fri, Oct 24, 2008 at 02:29:18PM +0900, KOSAKI Motohiro wrote:
> > > > > I don't see a better way to solve it, other than avoiding lru_add_drain_all
> > > > 
> > > > Well,
> > > > 
> > > > Unfortunately, lru_add_drain_all is also used some other VM place
> > > > (page migration and memory hotplug).
> > > > and page migration's usage is the same of this mlock usage.
> > > > (1. grab mmap_sem  2.  call lru_add_drain_all)
> > > > 
> > > > Then, change mlock usage isn't solution ;-)
> > > 
> > > No, not mlock alone.
> > 
> > Ah, I see.
> > It seems difficult but valuable. I'll think this way for a while.
> 
> Well, I think it would be nice if we can reduce lru_add_drain_all,
> however your patch might be the least intrusive and best short term
> solution.

Yup, thanks.

I also think my way is the best solustion of 2.6.28 age.
and I should work on your better solution for long term.