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From: Mel Gorman <mgorman@suse.de>
To: Christoph Lameter <cl@linux.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Jiri Slaby <jslaby@suse.cz>,
	Valdis Kletnieks <Valdis.Kletnieks@vt.edu>,
	Rik van Riel <riel@redhat.com>,
	Zlatko Calusic <zcalusic@bitsync.net>,
	Johannes Weiner <hannes@cmpxchg.org>,
	dormando <dormando@rydia.net>,
	Satoru Moriya <satoru.moriya@hds.com>,
	Michal Hocko <mhocko@suse.cz>, Linux-MM <linux-mm@kvack.org>,
	LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 0/10] Reduce system disruption due to kswapd V2
Date: Wed, 10 Apr 2013 15:14:45 +0100	[thread overview]
Message-ID: <20130410141445.GD3710@suse.de> (raw)
In-Reply-To: <0000013defd666bf-213d70fc-dfbd-4a50-82ed-e9f4f7391b55-000000@email.amazonses.com>

On Tue, Apr 09, 2013 at 05:27:18PM +0000, Christoph Lameter wrote:
> One additional measure that may be useful is to make kswapd prefer one
> specific processor on a socket. Two benefits arise from that:
> 
> 1. Better use of cpu caches and therefore higher speed, less
> serialization.
> 

Considering the volume of pages that kswapd can scan when it's active
I would expect that it trashes its cache anyway. The L1 cache would be
flushed after scanning struct pages for just a few MB of memory.

> 2. Reduction of the disturbances to one processor.
> 

I've never checked it but I would have expected kswapd to stay on the
same processor for significant periods of time. Have you experienced
problems where kswapd bounces around on CPUs within a node causing
workload disruption?

-- 
Mel Gorman
SUSE Labs

  reply	other threads:[~2013-04-10 14:14 UTC|newest]

Thread overview: 42+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-04-09 11:06 [PATCH 0/10] Reduce system disruption due to kswapd V2 Mel Gorman
2013-04-09 11:06 ` [PATCH 01/10] mm: vmscan: Limit the number of pages kswapd reclaims at each priority Mel Gorman
2013-04-09 13:27   ` Michal Hocko
2013-04-10  6:47   ` Kamezawa Hiroyuki
2013-04-09 11:06 ` [PATCH 02/10] mm: vmscan: Obey proportional scanning requirements for kswapd Mel Gorman
2013-04-10  7:16   ` Kamezawa Hiroyuki
2013-04-10 14:08     ` Mel Gorman
2013-04-11  0:14       ` Kamezawa Hiroyuki
2013-04-11  9:09         ` Mel Gorman
2013-04-09 11:06 ` [PATCH 03/10] mm: vmscan: Flatten kswapd priority loop Mel Gorman
2013-04-10  7:47   ` Kamezawa Hiroyuki
2013-04-10 13:29     ` Mel Gorman
2013-04-12  2:45   ` Rik van Riel
2013-04-09 11:06 ` [PATCH 04/10] mm: vmscan: Decide whether to compact the pgdat based on reclaim progress Mel Gorman
2013-04-10  8:05   ` Kamezawa Hiroyuki
2013-04-10 13:57     ` Mel Gorman
2013-04-12  2:46   ` Rik van Riel
2013-04-09 11:07 ` [PATCH 05/10] mm: vmscan: Do not allow kswapd to scan at maximum priority Mel Gorman
2013-04-09 11:07 ` [PATCH 06/10] mm: vmscan: Have kswapd writeback pages based on dirty pages encountered, not priority Mel Gorman
2013-04-12  2:51   ` Rik van Riel
2013-04-09 11:07 ` [PATCH 07/10] mm: vmscan: Block kswapd if it is encountering pages under writeback Mel Gorman
2013-04-12  2:54   ` Rik van Riel
2013-04-09 11:07 ` [PATCH 08/10] mm: vmscan: Have kswapd shrink slab only once per priority Mel Gorman
2013-04-09 11:07 ` [PATCH 09/10] mm: vmscan: Check if kswapd should writepage once per pgdat scan Mel Gorman
2013-04-09 11:07 ` [PATCH 10/10] mm: vmscan: Move logic from balance_pgdat() to kswapd_shrink_zone() Mel Gorman
2013-04-12  2:56   ` Rik van Riel
2013-04-09 17:27 ` [PATCH 0/10] Reduce system disruption due to kswapd V2 Christoph Lameter
2013-04-10 14:14   ` Mel Gorman [this message]
2013-04-10 22:28     ` dormando
2013-04-10 23:46       ` KOSAKI Motohiro
2013-04-11  9:10       ` Mel Gorman
2013-04-11 20:13         ` Michal Hocko
2013-04-11 20:55 ` Zlatko Calusic
2013-04-12 19:40   ` Mel Gorman
2013-04-12 19:52     ` Mel Gorman
2013-04-12 20:07     ` Zlatko Calusic
2013-04-12 20:41       ` Mel Gorman
2013-04-12 21:14         ` Zlatko Calusic
2013-04-22  6:37       ` Zlatko Calusic
2013-04-22  6:43         ` Simon Jeons
2013-04-22  6:54           ` Zlatko Calusic
2013-04-22  7:12             ` Simon Jeons

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