From: Christoph Lameter <cl@linux.com>
To: Mel Gorman <mgorman@suse.de>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Minchan Kim <minchan.kim@gmail.com>,
KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/2] mm: page allocator: Initialise ZLC for first zone eligible for zone_reclaim
Date: Mon, 18 Jul 2011 09:56:31 -0500 (CDT) [thread overview]
Message-ID: <alpine.DEB.2.00.1107180951390.30392@router.home> (raw)
In-Reply-To: <1310742540-22780-2-git-send-email-mgorman@suse.de>
On Fri, 15 Jul 2011, Mel Gorman wrote:
> Currently the zonelist cache is setup only after the first zone has
> been considered and zone_reclaim() has been called. The objective was
> to avoid a costly setup but zone_reclaim is itself quite expensive. If
> it is failing regularly such as the first eligible zone having mostly
> mapped pages, the cost in scanning and allocation stalls is far higher
> than the ZLC initialisation step.
Would it not be easier to set zlc_active and allowednodes based on the
zone having an active ZLC at the start of get_pages()?
Buffered_rmqueue is handling the situation of a zone with an ZLC in a
weird way right now since it ignores the (potentially existing) ZLC
for the first pass. zlc_setup() does a lot of things. So that is because
there is a performance benefit?
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next prev parent reply other threads:[~2011-07-18 14:56 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-07-15 15:08 [PATCH 0/2] Reduce frequency of stalls due to zone_reclaim() on NUMA v2r1 Mel Gorman
2011-07-15 15:08 ` [PATCH 1/2] mm: page allocator: Initialise ZLC for first zone eligible for zone_reclaim Mel Gorman
2011-07-18 14:56 ` Christoph Lameter [this message]
2011-07-18 16:05 ` Mel Gorman
2011-07-18 17:20 ` Christoph Lameter
2011-07-18 21:13 ` Mel Gorman
2011-07-18 21:54 ` Christoph Lameter
2011-07-19 14:01 ` Christoph Lameter
2011-07-20 18:08 ` Christoph Lameter
2011-07-20 19:18 ` Mel Gorman
2011-07-20 19:28 ` Christoph Lameter
2011-07-20 19:52 ` Christoph Lameter
2011-07-20 21:17 ` Christoph Lameter
2011-07-20 22:48 ` Mel Gorman
2011-07-21 15:24 ` Christoph Lameter
2011-07-15 15:09 ` [PATCH 2/2] mm: page allocator: Reconsider zones for allocation after direct reclaim Mel Gorman
2011-07-19 11:46 ` [PATCH] mm: page allocator: Reconsider zones for allocation after direct reclaim fix Mel Gorman
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