From: Michal Hocko <mhocko@suse.cz>
To: Mel Gorman <mgorman@suse.de>
Cc: Linux-MM <linux-mm@kvack.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>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 05/10] mm: vmscan: Do not allow kswapd to scan at maximum priority
Date: Thu, 21 Mar 2013 16:48:10 +0100 [thread overview]
Message-ID: <20130321154810.GR6094@dhcp22.suse.cz> (raw)
In-Reply-To: <1363525456-10448-6-git-send-email-mgorman@suse.de>
On Sun 17-03-13 13:04:11, Mel Gorman wrote:
> Page reclaim at priority 0 will scan the entire LRU as priority 0 is
> considered to be a near OOM condition. Kswapd can reach priority 0 quite
> easily if it is encountering a large number of pages it cannot reclaim
> such as pages under writeback. When this happens, kswapd reclaims very
> aggressively even though there may be no real risk of allocation failure
> or OOM.
>
> This patch prevents kswapd reaching priority 0 and trying to reclaim
> the world. Direct reclaimers will still reach priority 0 in the event
> of an OOM situation.
OK, it should work. raise_priority should prevent from pointless
lowerinng the priority and if there is really nothing to reclaim then
relying on the direct reclaim is probably a better idea.
> Signed-off-by: Mel Gorman <mgorman@suse.de>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
> ---
> mm/vmscan.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/mm/vmscan.c b/mm/vmscan.c
> index 7513bd1..af3bb6f 100644
> --- a/mm/vmscan.c
> +++ b/mm/vmscan.c
> @@ -2891,7 +2891,7 @@ static unsigned long balance_pgdat(pg_data_t *pgdat, int order,
> */
> if (raise_priority || !this_reclaimed)
> sc.priority--;
> - } while (sc.priority >= 0 &&
> + } while (sc.priority >= 1 &&
> !pgdat_balanced(pgdat, order, *classzone_idx));
>
> out:
> --
> 1.8.1.4
>
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2013-03-21 15:48 UTC|newest]
Thread overview: 123+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-03-17 13:04 [RFC PATCH 0/8] Reduce system disruption due to kswapd Mel Gorman
2013-03-17 13:04 ` [PATCH 01/10] mm: vmscan: Limit the number of pages kswapd reclaims at each priority Mel Gorman
2013-03-18 23:53 ` Simon Jeons
2013-03-19 9:55 ` Mel Gorman
2013-03-19 10:16 ` Simon Jeons
2013-03-19 10:59 ` Mel Gorman
2013-03-20 16:18 ` Michal Hocko
2013-03-21 0:52 ` Rik van Riel
2013-03-22 0:08 ` Will Huck
2013-03-21 9:47 ` Mel Gorman
2013-03-21 12:59 ` Michal Hocko
2013-03-21 0:51 ` Rik van Riel
2013-03-21 15:57 ` Johannes Weiner
2013-03-21 16:47 ` Mel Gorman
2013-03-22 0:05 ` Will Huck
2013-03-22 3:52 ` Rik van Riel
2013-03-22 3:56 ` Will Huck
2013-03-22 4:59 ` Will Huck
2013-03-22 13:01 ` Rik van Riel
2013-04-05 0:05 ` Will Huck
2013-04-07 7:32 ` Will Huck
2013-04-07 7:35 ` Will Huck
2013-04-11 5:54 ` Will Huck
2013-04-11 5:58 ` Will Huck
2013-04-12 5:46 ` Ric Mason
2013-04-12 9:34 ` Mel Gorman
2013-04-12 13:40 ` Rik van Riel
2013-03-25 9:07 ` Michal Hocko
2013-03-25 9:13 ` Jiri Slaby
2013-03-28 22:31 ` Jiri Slaby
2013-03-29 8:22 ` Michal Hocko
2013-03-30 22:07 ` Jiri Slaby
2013-04-02 11:15 ` Mel Gorman
2013-03-17 13:04 ` [PATCH 02/10] mm: vmscan: Obey proportional scanning requirements for kswapd Mel Gorman
2013-03-17 14:39 ` Andi Kleen
2013-03-17 15:08 ` Mel Gorman
2013-03-21 1:10 ` Rik van Riel
2013-03-21 9:54 ` Mel Gorman
2013-03-21 14:01 ` Michal Hocko
2013-03-21 14:31 ` Mel Gorman
2013-03-21 15:07 ` Michal Hocko
2013-03-21 15:34 ` Mel Gorman
2013-03-22 7:54 ` Michal Hocko
2013-03-22 8:37 ` Mel Gorman
2013-03-22 10:04 ` Michal Hocko
2013-03-22 10:47 ` Michal Hocko
2013-03-21 16:25 ` Johannes Weiner
2013-03-21 18:02 ` Mel Gorman
2013-03-22 16:53 ` Johannes Weiner
2013-03-22 18:25 ` Mel Gorman
2013-03-22 19:09 ` Johannes Weiner
2013-03-22 19:46 ` 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
2013-03-17 13:04 ` [PATCH 04/10] mm: vmscan: Decide whether to compact the pgdat based on reclaim progress Mel Gorman
2013-03-18 11:35 ` Hillf Danton
2013-03-19 10:27 ` Mel Gorman
[not found] ` <20130318111130.GA7245@hacker.(null)>
2013-03-19 10:19 ` Mel Gorman
2013-03-21 15:32 ` Michal Hocko
2013-03-21 15:47 ` Mel Gorman
2013-03-21 15:50 ` Michal Hocko
2013-03-17 13:04 ` [PATCH 05/10] mm: vmscan: Do not allow kswapd to scan at maximum priority Mel Gorman
2013-03-21 1:20 ` Rik van Riel
2013-03-21 10:12 ` Mel Gorman
2013-03-21 12:30 ` Rik van Riel
2013-03-21 15:48 ` Michal Hocko [this message]
2013-03-17 13:04 ` [PATCH 06/10] mm: vmscan: Have kswapd writeback pages based on dirty pages encountered, not priority Mel Gorman
2013-03-17 14:42 ` Andi Kleen
2013-03-17 15:11 ` Mel Gorman
2013-03-21 17:53 ` Rik van Riel
2013-03-21 18:15 ` Mel Gorman
2013-03-21 18:21 ` Rik van Riel
[not found] ` <20130318110850.GA7144@hacker.(null)>
2013-03-19 10:35 ` Mel Gorman
2013-03-17 13:04 ` [PATCH 07/10] mm: vmscan: Block kswapd if it is encountering pages under writeback Mel Gorman
2013-03-17 14:49 ` Andi Kleen
2013-03-17 15:19 ` Mel Gorman
2013-03-17 15:40 ` Andi Kleen
2013-03-19 11:06 ` Mel Gorman
2013-03-18 11:37 ` Simon Jeons
2013-03-19 10:57 ` Mel Gorman
[not found] ` <20130318115827.GB7245@hacker.(null)>
2013-03-19 10:58 ` Mel Gorman
2013-03-21 16:32 ` [PATCH 07/10 -v2r1] " Michal Hocko
2013-03-21 18:42 ` [PATCH 07/10] " Rik van Riel
2013-03-22 8:27 ` Mel Gorman
2013-03-17 13:04 ` [PATCH 08/10] mm: vmscan: Have kswapd shrink slab only once per priority Mel Gorman
2013-03-17 14:53 ` Andi Kleen
2013-03-21 16:47 ` Michal Hocko
2013-03-21 19:47 ` Rik van Riel
2013-04-09 6:53 ` Joonsoo Kim
2013-04-09 8:41 ` Simon Jeons
2013-04-09 11:13 ` Mel Gorman
2013-04-10 1:07 ` Dave Chinner
2013-04-10 5:23 ` Joonsoo Kim
2013-04-11 9:53 ` Mel Gorman
2013-04-10 5:21 ` Joonsoo Kim
2013-04-11 10:01 ` Mel Gorman
2013-04-11 10:29 ` Ric Mason
2013-03-17 13:04 ` [PATCH 09/10] mm: vmscan: Check if kswapd should writepage " Mel Gorman
2013-03-21 16:58 ` Michal Hocko
2013-03-21 18:07 ` Mel Gorman
2013-03-21 19:52 ` Rik van Riel
2013-03-17 13:04 ` [PATCH 10/10] mm: vmscan: Move logic from balance_pgdat() to kswapd_shrink_zone() Mel Gorman
2013-03-17 14:55 ` Andi Kleen
2013-03-17 15:25 ` Mel Gorman
2013-03-21 17:18 ` Michal Hocko
2013-03-21 18:13 ` Mel Gorman
2013-03-22 14:37 ` [RFC PATCH 0/8] Reduce system disruption due to kswapd Mel Gorman
2013-03-24 19:00 ` Jiri Slaby
2013-03-25 8:17 ` Michal Hocko
2013-04-09 11:06 [PATCH 0/10] Reduce system disruption due to kswapd V2 Mel Gorman
2013-04-09 11:07 ` [PATCH 05/10] mm: vmscan: Do not allow kswapd to scan at maximum priority Mel Gorman
2013-04-11 19:57 [PATCH 0/10] Reduce system disruption due to kswapd V3 Mel Gorman
2013-04-11 19:57 ` [PATCH 05/10] mm: vmscan: Do not allow kswapd to scan at maximum priority Mel Gorman
2013-04-18 15:11 ` Johannes Weiner
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