From: Christoph Lameter <cl@linux.com>
To: Mel Gorman <mel@csn.ul.ie>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Linux Kernel List <linux-kernel@vger.kernel.org>,
linux-mm@kvack.org, Rik van Riel <riel@redhat.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Minchan Kim <minchan.kim@gmail.com>,
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Subject: Re: [PATCH 2/3] mm: page allocator: Calculate a better estimate of NR_FREE_PAGES when memory is low and kswapd is awake
Date: Mon, 23 Aug 2010 08:41:56 -0500 (CDT) [thread overview]
Message-ID: <alpine.DEB.2.00.1008230838320.5750@router.home> (raw)
In-Reply-To: <20100823130315.GQ19797@csn.ul.ie>
On Mon, 23 Aug 2010, Mel Gorman wrote:
> > The delta of the counters could also be reduced to increase accuracy.
> > See refresh_zone_stat_thresholds().
> True, but I thought that would introduce a constant performance penalty
> for a corner case which I didn't like.
Sure, an increased frequency of updates would increase the chance of
bouncing cachelines. But the bouncing cacheline scenario for the vm
counters was tuned for applications that continually allocate pages in
parallel.
When the vm gets into a state where continual reclaim is necessary then
the counters are not that frequently updated. If the machine is already
slowing down due to reclaim then the vm can likely affort more frequent
counter updates.
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next prev parent reply other threads:[~2010-08-23 13:42 UTC|newest]
Thread overview: 67+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-08-23 8:00 [PATCH 0/3] Reduce watermark-related problems with the per-cpu allocator V2 Mel Gorman
2010-08-23 8:00 ` [PATCH 1/3] mm: page allocator: Update free page counters after pages are placed on the free list Mel Gorman
2010-08-23 12:47 ` Christoph Lameter
2010-08-23 8:00 ` [PATCH 2/3] mm: page allocator: Calculate a better estimate of NR_FREE_PAGES when memory is low and kswapd is awake Mel Gorman
2010-08-23 12:56 ` Christoph Lameter
2010-08-23 13:03 ` Mel Gorman
2010-08-23 13:41 ` Christoph Lameter [this message]
2010-08-23 13:55 ` Mel Gorman
2010-08-23 16:04 ` Christoph Lameter
2010-08-23 16:13 ` Mel Gorman
2010-08-23 8:00 ` [PATCH 3/3] mm: page allocator: Drain per-cpu lists after direct reclaim allocation fails Mel Gorman
2010-08-23 23:17 ` KOSAKI Motohiro
2010-08-23 12:45 ` [PATCH 0/3] Reduce watermark-related problems with the per-cpu allocator V2 Christoph Lameter
2010-08-23 13:01 ` Mel Gorman
2010-08-23 13:38 ` Christoph Lameter
2010-08-23 13:39 ` Mel Gorman
-- strict thread matches above, loose matches on Subject: below --
2010-09-03 9:08 [PATCH 0/3] Reduce watermark-related problems with the per-cpu allocator V4 Mel Gorman
2010-09-03 9:08 ` [PATCH 2/3] mm: page allocator: Calculate a better estimate of NR_FREE_PAGES when memory is low and kswapd is awake Mel Gorman
2010-09-03 22:55 ` Andrew Morton
2010-09-03 23:17 ` Christoph Lameter
2010-09-03 23:28 ` Andrew Morton
2010-09-04 0:54 ` Christoph Lameter
2010-09-05 18:12 ` Mel Gorman
2010-08-31 17:37 [PATCH 0/3] Reduce watermark-related problems with the per-cpu allocator V3 Mel Gorman
2010-08-31 17:37 ` [PATCH 2/3] mm: page allocator: Calculate a better estimate of NR_FREE_PAGES when memory is low and kswapd is awake Mel Gorman
2010-08-31 18:20 ` Christoph Lameter
2010-08-31 23:37 ` KOSAKI Motohiro
2010-09-01 7:24 ` Mel Gorman
2010-09-01 7:33 ` KOSAKI Motohiro
2010-09-01 20:16 ` Christoph Lameter
2010-09-01 20:34 ` Mel Gorman
2010-09-02 0:24 ` Christoph Lameter
2010-09-02 0:26 ` KOSAKI Motohiro
2010-09-02 0:39 ` Christoph Lameter
2010-09-02 0:54 ` Christoph Lameter
2010-09-02 0:43 ` Christoph Lameter
2010-09-02 0:49 ` KOSAKI Motohiro
2010-09-02 8:51 ` Mel Gorman
2010-08-16 9:42 [RFC PATCH 0/3] Reduce watermark-related problems with the per-cpu allocator Mel Gorman
2010-08-16 9:42 ` [PATCH 2/3] mm: page allocator: Calculate a better estimate of NR_FREE_PAGES when memory is low and kswapd is awake Mel Gorman
2010-08-16 9:43 ` Mel Gorman
2010-08-16 14:47 ` Rik van Riel
2010-08-16 16:06 ` Johannes Weiner
2010-08-17 2:26 ` Minchan Kim
2010-08-17 10:42 ` Mel Gorman
2010-08-17 15:01 ` Minchan Kim
2010-08-17 15:05 ` Mel Gorman
2010-08-17 10:16 ` Mel Gorman
2010-08-17 11:05 ` Johannes Weiner
2010-08-17 14:20 ` Minchan Kim
2010-08-18 8:51 ` Mel Gorman
2010-08-18 14:57 ` Minchan Kim
2010-08-19 8:06 ` Mel Gorman
2010-08-19 10:33 ` Minchan Kim
2010-08-19 10:38 ` Mel Gorman
2010-08-19 14:01 ` Minchan Kim
2010-08-19 14:09 ` Mel Gorman
2010-08-19 14:34 ` Minchan Kim
2010-08-19 15:07 ` Mel Gorman
2010-08-19 15:22 ` Minchan Kim
2010-08-19 15:40 ` Mel Gorman
2010-08-19 15:44 ` Minchan Kim
2010-08-19 15:46 ` Minchan Kim
2010-08-19 16:06 ` Mel Gorman
2010-08-19 16:45 ` Minchan Kim
2010-08-18 2:59 ` KAMEZAWA Hiroyuki
2010-08-18 15:55 ` Christoph Lameter
2010-08-19 0:07 ` KAMEZAWA Hiroyuki
2010-08-19 19:00 ` Christoph Lameter
2010-08-19 23:49 ` KAMEZAWA Hiroyuki
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