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From: Rik van Riel <>
Cc: lkml <>,
	Andrea Arcangeli <>,
	Mel Gorman <>, Johannes Weiner <>,
	Andrew Morton <>,
	Minchan Kim <>,
	KOSAKI Motohiro <>
Subject: [PATCH v3 -mm 0/3] kswapd vs compaction improvements
Date: Thu, 26 Jan 2012 14:54:50 -0500	[thread overview]
Message-ID: <> (raw)

Running a kernel with compaction enabled with some memory pressure has
caused my system to run into all kinds of trouble.

One of the more obvious problems is that while kswapd does not try to 
free contiguous pages when CONFIG_COMPACTION is enabled, it does
continue reclaiming until enough contiguous pages have become available.
This can lead to enormous swap storms, where lots of memory is freed
and a fair amount of the working set can end up in swap.

A second problem is that memory compaction currently does nothing for
network allocations in the receive path, for eg. jumbo frames, because
those are done in interrupt context.  In the past we have tried to
have kswapd invoke memory compaction, but it used too much CPU time.
The second patch in this series has kswapd invoke compaction very
carefully, taking in account the desired page order, as well as

I have tested these patches on my system, and things seem to behave
well. Any tests and reviews would be appreciated.

             reply	other threads:[~2012-01-26 20:03 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-01-26 19:54 Rik van Riel [this message]
2012-01-26 19:59 ` [PATCH v3 -mm 1/3] mm: reclaim at order 0 when compaction is enabled Rik van Riel
2012-01-27  9:13   ` Hillf Danton
2012-01-27 16:35     ` Rik van Riel
2012-01-30 10:26       ` Mel Gorman
2012-01-27 23:31   ` Andrew Morton
2012-01-29 13:25   ` Hillf Danton
2012-01-30 10:36   ` Mel Gorman
2012-01-26 19:59 ` [PATCH v3 -mm 2/3] mm: kswapd carefully call compaction Rik van Riel
2012-01-27 23:36   ` Andrew Morton
2012-01-26 20:01 ` [PATCH v3 -mm 3/3] mm: only defer compaction for failed order and higher Rik van Riel
2012-01-30 10:47   ` Mel Gorman

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