From: Mel Gorman <mgorman@suse.de>
Subject: Re: [RFC PATCH 0/3] Obey mark_page_accessed hint given by filesystems
Date: Wed, 1 May 2013 09:08:19 +0100
Message-ID: <20130501080819.GF11497@suse.de>
References: <1367253119-6461-1-git-send-email-mgorman@suse.de>
 <5180B601.8080005@gmail.com>
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Cc: Alexey Lyahkov <alexey.lyashkov@gmail.com>,
	Andrew Perepechko <anserper@ya.ru>, Robin Dong <sanbai@taobao.com>,
	Theodore Tso <tytso@mit.edu>,
	Andrew Morton <akpm@linux-foundation.org>,
	Hugh Dickins <hughd@google.com>, Rik van Riel <riel@redhat.com>,
	Johannes Weiner <hannes@cmpxchg.org>,
	Bernd Schubert <bernd.schubert@fastmail.fm>,
	David Howells <dhowells@redhat.com>,
	Trond Myklebust <Trond.Myklebust@netapp.com>,
	Linux-fsdevel <linux-fsdevel@vger.kernel.org>,
	Linux-ext4 <linux-ext4@vger.kernel.org>,
	LKML <linux-kernel@vger.kernel.org>, Linux-mm <linux-mm@kvack.org>
To: Will Huck <will.huckk@gmail.com>
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On Wed, May 01, 2013 at 02:28:17PM +0800, Will Huck wrote:
> Hi Mel,
> On 04/30/2013 12:31 AM, Mel Gorman wrote:
> >Andrew Perepechko reported a problem whereby pages are being prematurely
> >evicted as the mark_page_accessed() hint is ignored for pages that are
> >currently on a pagevec -- http://www.spinics.net/lists/linux-ext4/msg37340.html .
> >Alexey Lyahkov and Robin Dong have also reported problems recently that
> >could be due to hot pages reaching the end of the inactive list too quickly
> >and be reclaimed.
> 
> Both shrink_active_list and shrink_inactive_list can call
> lru_add_drain(), why the hot pages can't be mark Actived during this
> time?
> 

Because by then it's not known that the filesystem had called
mark_page_accessed() to indicate the page should be activated.

-- 
Mel Gorman
SUSE Labs

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