From: Andrew Morton <akpm@linux-foundation.org>
To: Mel Gorman <mel@csn.ul.ie>
Cc: linux-mm@kvack.org, Nick Piggin <npiggin@suse.de>,
Christian Ehrhardt <ehrhardt@linux.vnet.ibm.com>,
Chris Mason <chris.mason@oracle.com>,
Jens Axboe <jens.axboe@oracle.com>,
linux-kernel@vger.kernel.org
Subject: Re: [RFC PATCH 0/3] Avoid the use of congestion_wait under zone pressure
Date: Thu, 11 Mar 2010 15:41:24 -0800 [thread overview]
Message-ID: <20100311154124.e1e23900.akpm@linux-foundation.org> (raw)
In-Reply-To: <1268048904-19397-1-git-send-email-mel@csn.ul.ie>
On Mon, 8 Mar 2010 11:48:20 +0000
Mel Gorman <mel@csn.ul.ie> wrote:
> Under memory pressure, the page allocator and kswapd can go to sleep using
> congestion_wait(). In two of these cases, it may not be the appropriate
> action as congestion may not be the problem.
clear_bdi_congested() is called each time a write completes and the
queue is below the congestion threshold.
So if the page allocator or kswapd call congestion_wait() against a
non-congested queue, they'll wake up on the very next write completion.
Hence the above-quoted claim seems to me to be a significant mis-analysis and
perhaps explains why the patchset didn't seem to help anything?
WARNING: multiple messages have this Message-ID (diff)
From: Andrew Morton <akpm@linux-foundation.org>
To: Mel Gorman <mel@csn.ul.ie>
Cc: linux-mm@kvack.org, Nick Piggin <npiggin@suse.de>,
Christian Ehrhardt <ehrhardt@linux.vnet.ibm.com>,
Chris Mason <chris.mason@oracle.com>,
Jens Axboe <jens.axboe@oracle.com>,
linux-kernel@vger.kernel.org
Subject: Re: [RFC PATCH 0/3] Avoid the use of congestion_wait under zone pressure
Date: Thu, 11 Mar 2010 15:41:24 -0800 [thread overview]
Message-ID: <20100311154124.e1e23900.akpm@linux-foundation.org> (raw)
In-Reply-To: <1268048904-19397-1-git-send-email-mel@csn.ul.ie>
On Mon, 8 Mar 2010 11:48:20 +0000
Mel Gorman <mel@csn.ul.ie> wrote:
> Under memory pressure, the page allocator and kswapd can go to sleep using
> congestion_wait(). In two of these cases, it may not be the appropriate
> action as congestion may not be the problem.
clear_bdi_congested() is called each time a write completes and the
queue is below the congestion threshold.
So if the page allocator or kswapd call congestion_wait() against a
non-congested queue, they'll wake up on the very next write completion.
Hence the above-quoted claim seems to me to be a significant mis-analysis and
perhaps explains why the patchset didn't seem to help anything?
--
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next prev parent reply other threads:[~2010-03-11 23:42 UTC|newest]
Thread overview: 136+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-03-08 11:48 [RFC PATCH 0/3] Avoid the use of congestion_wait under zone pressure Mel Gorman
2010-03-08 11:48 ` Mel Gorman
2010-03-08 11:48 ` [PATCH 1/3] page-allocator: Under memory pressure, wait on pressure to relieve instead of congestion Mel Gorman
2010-03-08 11:48 ` Mel Gorman
2010-03-09 13:35 ` Nick Piggin
2010-03-09 13:35 ` Nick Piggin
2010-03-09 14:17 ` Mel Gorman
2010-03-09 14:17 ` Mel Gorman
2010-03-09 15:03 ` Nick Piggin
2010-03-09 15:03 ` Nick Piggin
2010-03-09 15:42 ` Christian Ehrhardt
2010-03-09 15:42 ` Christian Ehrhardt
2010-03-09 18:22 ` Mel Gorman
2010-03-09 18:22 ` Mel Gorman
2010-03-10 2:38 ` Nick Piggin
2010-03-10 2:38 ` Nick Piggin
2010-03-09 17:35 ` Mel Gorman
2010-03-09 17:35 ` Mel Gorman
2010-03-10 2:35 ` Nick Piggin
2010-03-10 2:35 ` Nick Piggin
2010-03-09 15:50 ` Christoph Lameter
2010-03-09 15:50 ` Christoph Lameter
2010-03-09 15:56 ` Christian Ehrhardt
2010-03-09 15:56 ` Christian Ehrhardt
2010-03-09 16:09 ` Christoph Lameter
2010-03-09 16:09 ` Christoph Lameter
2010-03-09 17:01 ` Mel Gorman
2010-03-09 17:01 ` Mel Gorman
2010-03-09 17:11 ` Christoph Lameter
2010-03-09 17:11 ` Christoph Lameter
2010-03-09 17:30 ` Mel Gorman
2010-03-09 17:30 ` Mel Gorman
2010-03-08 11:48 ` [PATCH 2/3] page-allocator: Check zone pressure when batch of pages are freed Mel Gorman
2010-03-08 11:48 ` Mel Gorman
2010-03-09 9:53 ` Nick Piggin
2010-03-09 9:53 ` Nick Piggin
2010-03-09 10:08 ` Mel Gorman
2010-03-09 10:08 ` Mel Gorman
2010-03-09 10:23 ` Nick Piggin
2010-03-09 10:23 ` Nick Piggin
2010-03-09 10:36 ` Mel Gorman
2010-03-09 10:36 ` Mel Gorman
2010-03-09 11:11 ` Nick Piggin
2010-03-09 11:11 ` Nick Piggin
2010-03-09 11:29 ` Mel Gorman
2010-03-09 11:29 ` Mel Gorman
2010-03-08 11:48 ` [PATCH 3/3] vmscan: Put kswapd to sleep on its own waitqueue, not congestion Mel Gorman
2010-03-08 11:48 ` Mel Gorman
2010-03-09 10:00 ` Nick Piggin
2010-03-09 10:00 ` Nick Piggin
2010-03-09 10:21 ` Mel Gorman
2010-03-09 10:21 ` Mel Gorman
2010-03-09 10:32 ` Nick Piggin
2010-03-09 10:32 ` Nick Piggin
2010-03-11 23:41 ` Andrew Morton [this message]
2010-03-11 23:41 ` [RFC PATCH 0/3] Avoid the use of congestion_wait under zone pressure Andrew Morton
2010-03-12 6:39 ` Christian Ehrhardt
2010-03-12 6:39 ` Christian Ehrhardt
2010-03-12 7:05 ` Andrew Morton
2010-03-12 7:05 ` Andrew Morton
2010-03-12 10:47 ` Mel Gorman
2010-03-12 10:47 ` Mel Gorman
2010-03-12 12:15 ` Christian Ehrhardt
2010-03-12 12:15 ` Christian Ehrhardt
2010-03-12 14:37 ` Andrew Morton
2010-03-12 14:37 ` Andrew Morton
2010-03-15 12:29 ` Mel Gorman
2010-03-15 12:29 ` Mel Gorman
2010-03-15 14:45 ` Christian Ehrhardt
2010-03-15 14:45 ` Christian Ehrhardt
2010-03-15 12:34 ` Christian Ehrhardt
2010-03-15 12:34 ` Christian Ehrhardt
2010-03-15 20:09 ` Andrew Morton
2010-03-15 20:09 ` Andrew Morton
2010-03-16 10:11 ` Mel Gorman
2010-03-16 10:11 ` Mel Gorman
2010-03-18 17:42 ` Mel Gorman
2010-03-18 17:42 ` Mel Gorman
2010-03-22 23:50 ` Mel Gorman
2010-03-22 23:50 ` Mel Gorman
2010-03-23 14:35 ` Christian Ehrhardt
2010-03-23 14:35 ` Christian Ehrhardt
2010-03-23 21:35 ` Corrado Zoccolo
2010-03-23 21:35 ` Corrado Zoccolo
2010-03-24 11:48 ` Mel Gorman
2010-03-24 11:48 ` Mel Gorman
2010-03-24 12:56 ` Corrado Zoccolo
2010-03-24 12:56 ` Corrado Zoccolo
2010-03-23 22:29 ` Rik van Riel
2010-03-23 22:29 ` Rik van Riel
2010-03-24 14:50 ` Mel Gorman
2010-03-24 14:50 ` Mel Gorman
2010-04-19 12:22 ` Christian Ehrhardt
2010-04-19 12:22 ` Christian Ehrhardt
2010-04-19 21:44 ` Johannes Weiner
2010-04-19 21:44 ` Johannes Weiner
2010-04-20 7:20 ` Christian Ehrhardt
2010-04-20 7:20 ` Christian Ehrhardt
2010-04-20 8:54 ` Christian Ehrhardt
2010-04-20 8:54 ` Christian Ehrhardt
2010-04-20 15:32 ` Johannes Weiner
2010-04-20 15:32 ` Johannes Weiner
2010-04-20 17:22 ` Rik van Riel
2010-04-20 17:22 ` Rik van Riel
2010-04-21 4:23 ` Christian Ehrhardt
2010-04-21 4:23 ` Christian Ehrhardt
2010-04-21 7:35 ` Christian Ehrhardt
2010-04-21 7:35 ` Christian Ehrhardt
2010-04-21 13:19 ` Rik van Riel
2010-04-21 13:19 ` Rik van Riel
2010-04-22 6:21 ` Christian Ehrhardt
2010-04-22 6:21 ` Christian Ehrhardt
2010-04-26 10:59 ` Subject: [PATCH][RFC] mm: make working set portion that is protected tunable v2 Christian Ehrhardt
2010-04-26 10:59 ` Christian Ehrhardt
2010-04-26 11:59 ` KOSAKI Motohiro
2010-04-26 11:59 ` KOSAKI Motohiro
2010-04-26 12:43 ` Christian Ehrhardt
2010-04-26 12:43 ` Christian Ehrhardt
2010-04-26 14:20 ` Rik van Riel
2010-04-26 14:20 ` Rik van Riel
2010-04-27 14:00 ` Christian Ehrhardt
2010-04-27 14:00 ` Christian Ehrhardt
2010-04-21 9:03 ` [RFC PATCH 0/3] Avoid the use of congestion_wait under zone pressure Johannes Weiner
2010-04-21 9:03 ` Johannes Weiner
2010-04-21 13:20 ` Rik van Riel
2010-04-21 13:20 ` Rik van Riel
2010-04-20 14:40 ` Rik van Riel
2010-04-20 14:40 ` Rik van Riel
2010-03-24 2:38 ` Greg KH
2010-03-24 2:38 ` Greg KH
2010-03-24 11:49 ` Mel Gorman
2010-03-24 11:49 ` Mel Gorman
2010-03-24 13:13 ` Johannes Weiner
2010-03-24 13:13 ` Johannes Weiner
2010-03-12 9:09 ` Mel Gorman
2010-03-12 9:09 ` Mel Gorman
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