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From: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
To: Peter Zijlstra <peterz@infradead.org>
Subject: Re: [RFC][PATCH] lru_add_drain_all() don't use schedule_on_each_cpu()
Cc: kosaki.motohiro@jp.fujitsu.com, Andrew Morton <akpm@linux-foundation.org>,
       Christoph Lameter <cl@linux-foundation.org>, heiko.carstens@de.ibm.com,
       npiggin@suse.de, linux-kernel@vger.kernel.org, hugh@veritas.com,
       torvalds@linux-foundation.org, riel@redhat.com, lee.schermerhorn@hp.com,
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Date: Wed,  5 Nov 2008 18:55:53 +0900 (JST)
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> On Wed, 2008-10-29 at 16:20 +0900, KOSAKI Motohiro wrote:
> > > I guess we should document our newly discovered schedule_on_each_cpu()
> > > problems before we forget about it and later rediscover it.
> > 
> > Now, schedule_on_each_cpu() is only used by lru_add_drain_all().
> > and smp_call_function() is better way for cross call.
> > 
> > So I propose
> >    1. lru_add_drain_all() use smp_call_function()
> >    2. remove schedule_on_each_cpu()
> > 
> > 
> > Thought?
> 
> At the very least that will not solve the problem on -rt where a lot of
> the smp_call_function() users are converted to schedule_on_each_cpu().

yup.
Now, I testing "simple dropping lru_add_drain_all() in mlock path" patch.

Thanks.