From: Rik van Riel <riel@redhat.com>
To: Mel Gorman <mgorman@suse.de>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Jiri Slaby <jslaby@suse.cz>,
Valdis Kletnieks <Valdis.Kletnieks@vt.edu>,
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 03/10] mm: vmscan: Flatten kswapd priority loop
Date: Thu, 11 Apr 2013 22:45:00 -0400 [thread overview]
Message-ID: <5167752C.6010703@redhat.com> (raw)
In-Reply-To: <1365505625-9460-4-git-send-email-mgorman@suse.de>
On 04/09/2013 07:06 AM, Mel Gorman wrote:
> kswapd stops raising the scanning priority when at least SWAP_CLUSTER_MAX
> pages have been reclaimed or the pgdat is considered balanced. It then
> rechecks if it needs to restart at DEF_PRIORITY and whether high-order
> reclaim needs to be reset. This is not wrong per-se but it is confusing
> to follow and forcing kswapd to stay at DEF_PRIORITY may require several
> restarts before it has scanned enough pages to meet the high watermark even
> at 100% efficiency. This patch irons out the logic a bit by controlling
> when priority is raised and removing the "goto loop_again".
>
> This patch has kswapd raise the scanning priority until it is scanning
> enough pages that it could meet the high watermark in one shrink of the
> LRU lists if it is able to reclaim at 100% efficiency. It will not raise
> the scanning prioirty higher unless it is failing to reclaim any pages.
>
> To avoid infinite looping for high-order allocation requests kswapd will
> not reclaim for high-order allocations when it has reclaimed at least
> twice the number of pages as the allocation request.
>
> Signed-off-by: Mel Gorman <mgorman@suse.de>
Reviewed-by: Rik van Riel <riel@redhat.com>
It looks like this patch could lead to near-infinite reclaiming when
higher-order reclaim is being done, but patch 4/10 should fix that...
--
All rights reversed
next prev parent reply other threads:[~2013-04-12 2:46 UTC|newest]
Thread overview: 57+ 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 [this message]
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
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
-- strict thread matches above, loose matches on Subject: below --
2013-04-11 19:57 [PATCH 0/10] Reduce system disruption due to kswapd V3 Mel Gorman
2013-04-11 19:57 ` [PATCH 03/10] mm: vmscan: Flatten kswapd priority loop Mel Gorman
2013-04-18 15:02 ` Johannes Weiner
2013-03-17 13:04 [RFC PATCH 0/8] Reduce system disruption due to kswapd Mel Gorman
2013-03-17 13:04 ` [PATCH 03/10] mm: vmscan: Flatten kswapd priority loop Mel Gorman
2013-03-17 14:36 ` Andi Kleen
2013-03-17 15:09 ` Mel Gorman
2013-03-18 23:58 ` Simon Jeons
2013-03-19 10:12 ` Mel Gorman
2013-03-19 3:08 ` Simon Jeons
2013-03-19 8:23 ` Michal Hocko
2013-03-19 10:14 ` Mel Gorman
2013-03-19 10:26 ` Simon Jeons
2013-03-19 11:01 ` Mel Gorman
2013-03-21 14:54 ` Michal Hocko
2013-03-21 15:26 ` Mel Gorman
2013-03-21 15:38 ` Michal Hocko
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