From: Rik van Riel <riel@redhat.com>
To: Mel Gorman <mgorman@suse.de>
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>,
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>
Subject: Re: [PATCH 2/3] mm: Ensure that mark_page_accessed moves pages to the active list
Date: Mon, 29 Apr 2013 13:12:03 -0400 [thread overview]
Message-ID: <517EA9E3.6050407@redhat.com> (raw)
In-Reply-To: <1367253119-6461-3-git-send-email-mgorman@suse.de>
On 04/29/2013 12:31 PM, Mel Gorman wrote:
> A PageActive page is now added to the inactivate list.
>
> While this looks strange, I think it is sufficiently harmless that additional
> barriers to address the case is not justified. Unfortunately, while I never
> witnessed it myself, these parallel updates potentially trigger defensive
> DEBUG_VM checks on PageActive and hence they are removed by this patch.
Could this not cause issues with __page_cache_release, called from
munmap, exit, truncate, etc.?
Could the eventual skewing of active vs inactive numbers break page
reclaim heuristics?
I wonder if we would need to move to a scheme where the PG_active bit
is always the authoritive one, and we never pass an overriding "lru"
parameter to __pagevec_lru_add.
Would memory ordering between SetPageLRU and testing for PageLRU be
enough to then prevent the statistics from going off?
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WARNING: multiple messages have this Message-ID (diff)
From: Rik van Riel <riel@redhat.com>
To: Mel Gorman <mgorman@suse.de>
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>,
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>
Subject: Re: [PATCH 2/3] mm: Ensure that mark_page_accessed moves pages to the active list
Date: Mon, 29 Apr 2013 13:12:03 -0400 [thread overview]
Message-ID: <517EA9E3.6050407@redhat.com> (raw)
In-Reply-To: <1367253119-6461-3-git-send-email-mgorman@suse.de>
On 04/29/2013 12:31 PM, Mel Gorman wrote:
> A PageActive page is now added to the inactivate list.
>
> While this looks strange, I think it is sufficiently harmless that additional
> barriers to address the case is not justified. Unfortunately, while I never
> witnessed it myself, these parallel updates potentially trigger defensive
> DEBUG_VM checks on PageActive and hence they are removed by this patch.
Could this not cause issues with __page_cache_release, called from
munmap, exit, truncate, etc.?
Could the eventual skewing of active vs inactive numbers break page
reclaim heuristics?
I wonder if we would need to move to a scheme where the PG_active bit
is always the authoritive one, and we never pass an overriding "lru"
parameter to __pagevec_lru_add.
Would memory ordering between SetPageLRU and testing for PageLRU be
enough to then prevent the statistics from going off?
--
All rights reversed
next prev parent reply other threads:[~2013-04-29 17:12 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-04-29 16:31 [RFC PATCH 0/3] Obey mark_page_accessed hint given by filesystems Mel Gorman
2013-04-29 16:31 ` Mel Gorman
2013-04-29 16:31 ` [PATCH 1/3] mm: pagevec: Defer deciding what LRU to add a page to until pagevec drain time Mel Gorman
2013-04-29 16:31 ` Mel Gorman
2013-04-29 16:50 ` Rik van Riel
2013-04-29 16:50 ` Rik van Riel
2013-05-03 7:51 ` Jan Kara
2013-05-03 7:51 ` Jan Kara
2013-05-03 8:37 ` Mel Gorman
2013-05-03 8:37 ` Mel Gorman
2013-04-29 16:31 ` [PATCH 2/3] mm: Ensure that mark_page_accessed moves pages to the active list Mel Gorman
2013-04-29 16:31 ` Mel Gorman
2013-04-29 17:12 ` Rik van Riel [this message]
2013-04-29 17:12 ` Rik van Riel
2013-04-29 21:53 ` Mel Gorman
2013-04-29 21:53 ` Mel Gorman
2013-05-01 5:41 ` Sam Ben
2013-05-01 5:41 ` Sam Ben
2013-05-01 8:06 ` Mel Gorman
2013-05-01 8:06 ` Mel Gorman
2013-05-01 8:14 ` Ric Mason
2013-05-01 8:14 ` Ric Mason
2013-05-01 8:31 ` Mel Gorman
2013-05-01 8:31 ` Mel Gorman
2013-04-29 16:31 ` [PATCH 3/3] mm: Remove lru parameter from __pagevec_lru_add and remove parts of pagevec API Mel Gorman
2013-04-29 16:31 ` Mel Gorman
2013-05-03 8:00 ` Jan Kara
2013-05-03 8:00 ` Jan Kara
2013-05-01 6:28 ` [RFC PATCH 0/3] Obey mark_page_accessed hint given by filesystems Will Huck
2013-05-01 6:28 ` Will Huck
2013-05-01 8:08 ` Mel Gorman
2013-05-01 8:08 ` Mel Gorman
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