From: Andrew Morton <akpm@linux-foundation.org>
To: Mel Gorman <mel@csn.ul.ie>
Cc: Andrea Arcangeli <aarcange@redhat.com>,
Christoph Lameter <cl@linux-foundation.org>,
Adam Litke <agl@us.ibm.com>, Avi Kivity <avi@redhat.com>,
David Rientjes <rientjes@google.com>,
Minchan Kim <minchan.kim@gmail.com>,
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
Rik van Riel <riel@redhat.com>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH 12/14] Add a tunable that decides when memory should be compacted and when it should be reclaimed
Date: Tue, 6 Apr 2010 17:06:13 -0700 [thread overview]
Message-ID: <20100406170613.9b80c7ea.akpm@linux-foundation.org> (raw)
In-Reply-To: <1270224168-14775-13-git-send-email-mel@csn.ul.ie>
On Fri, 2 Apr 2010 17:02:46 +0100
Mel Gorman <mel@csn.ul.ie> wrote:
> The kernel applies some heuristics when deciding if memory should be
> compacted or reclaimed to satisfy a high-order allocation. One of these
> is based on the fragmentation. If the index is below 500, memory will
> not be compacted. This choice is arbitrary and not based on data. To
> help optimise the system and set a sensible default for this value, this
> patch adds a sysctl extfrag_threshold. The kernel will only compact
> memory if the fragmentation index is above the extfrag_threshold.
Was this the most robust, reliable, no-2am-phone-calls thing we could
have done?
What about, say, just doing a bit of both until something worked? For
extra smarts we could remember what worked best last time, and make
ourselves more likely to try that next time.
Or whatever, but extfrag_threshold must die! And replacing it with a
hardwired constant doesn't count ;)
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next prev parent reply other threads:[~2010-04-07 0:06 UTC|newest]
Thread overview: 56+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-04-02 16:02 [PATCH 0/14] Memory Compaction v7 Mel Gorman
2010-04-02 16:02 ` [PATCH 01/14] mm,migration: Take a reference to the anon_vma before migrating Mel Gorman
2010-04-07 0:05 ` Andrew Morton
2010-04-07 9:56 ` Mel Gorman
2010-04-02 16:02 ` [PATCH 02/14] mm,migration: Do not try to migrate unmapped anonymous pages Mel Gorman
2010-04-02 16:02 ` [PATCH 03/14] mm: Share the anon_vma ref counts between KSM and page migration Mel Gorman
2010-04-07 0:05 ` Andrew Morton
2010-04-07 0:10 ` Rik van Riel
2010-04-07 10:01 ` Mel Gorman
2010-04-02 16:02 ` [PATCH 04/14] Allow CONFIG_MIGRATION to be set without CONFIG_NUMA or memory hot-remove Mel Gorman
2010-04-07 0:05 ` Andrew Morton
2010-04-07 10:22 ` Mel Gorman
2010-04-02 16:02 ` [PATCH 05/14] Export unusable free space index via /proc/unusable_index Mel Gorman
2010-04-07 0:05 ` Andrew Morton
2010-04-07 10:35 ` Mel Gorman
2010-04-13 12:42 ` Mel Gorman
2010-04-02 16:02 ` [PATCH 06/14] Export fragmentation index via /proc/extfrag_index Mel Gorman
2010-04-07 0:05 ` Andrew Morton
2010-04-07 10:46 ` Mel Gorman
2010-04-13 12:43 ` Mel Gorman
2010-04-02 16:02 ` [PATCH 07/14] Move definition for LRU isolation modes to a header Mel Gorman
2010-04-02 16:02 ` [PATCH 08/14] Memory compaction core Mel Gorman
2010-04-07 0:05 ` Andrew Morton
2010-04-07 15:21 ` Mel Gorman
2010-04-08 16:59 ` Mel Gorman
2010-04-08 17:06 ` Andrea Arcangeli
2010-04-02 16:02 ` [PATCH 09/14] Add /proc trigger for memory compaction Mel Gorman
2010-04-07 0:05 ` Andrew Morton
2010-04-07 15:39 ` Mel Gorman
2010-04-07 18:27 ` Mel Gorman
2010-04-02 16:02 ` [PATCH 10/14] Add /sys trigger for per-node " Mel Gorman
2010-04-07 0:05 ` Andrew Morton
2010-04-07 0:31 ` KAMEZAWA Hiroyuki
2010-04-06 21:56 ` Andrew Morton
2010-04-07 1:19 ` KAMEZAWA Hiroyuki
2010-04-07 15:42 ` Mel Gorman
2010-04-02 16:02 ` [PATCH 11/14] Direct compact when a high-order allocation fails Mel Gorman
2010-04-07 0:06 ` Andrew Morton
2010-04-07 16:06 ` Mel Gorman
2010-04-07 18:29 ` Mel Gorman
2010-04-02 16:02 ` [PATCH 12/14] Add a tunable that decides when memory should be compacted and when it should be reclaimed Mel Gorman
2010-04-07 0:06 ` Andrew Morton [this message]
2010-04-07 16:11 ` Mel Gorman
2010-04-02 16:02 ` [PATCH 13/14] Do not compact within a preferred zone after a compaction failure Mel Gorman
2010-04-07 0:06 ` Andrew Morton
2010-04-07 0:55 ` Andrea Arcangeli
2010-04-07 16:32 ` Mel Gorman
2010-04-02 16:02 ` [PATCH 14/14] mm,migration: Allow the migration of PageSwapCache pages Mel Gorman
2010-04-06 6:54 ` KAMEZAWA Hiroyuki
2010-04-06 15:37 ` Minchan Kim
2010-04-07 0:06 ` Andrew Morton
2010-04-07 16:49 ` Mel Gorman
2010-04-06 14:47 ` [PATCH 0/14] Memory Compaction v7 Tarkan Erimer
2010-04-06 15:00 ` Mel Gorman
2010-04-06 15:03 ` Tarkan Erimer
-- strict thread matches above, loose matches on Subject: below --
2010-03-30 9:14 [PATCH 0/14] Memory Compaction v6 Mel Gorman
2010-03-30 9:14 ` [PATCH 12/14] Add a tunable that decides when memory should be compacted and when it should be reclaimed Mel Gorman
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