From: Rik van Riel <riel@redhat.com>
To: Mel Gorman <mgorman@suse.de>
Cc: "Andrew Morton" <akpm@linux-foundation.org>,
"Pádraig Brady" <P@draigBrady.com>,
"James Bottomley" <James.Bottomley@HansenPartnership.com>,
"Colin King" <colin.king@canonical.com>,
"Minchan Kim" <minchan.kim@gmail.com>,
"Andrew Lutomirski" <luto@mit.edu>,
"Johannes Weiner" <hannes@cmpxchg.org>,
linux-mm <linux-mm@kvack.org>,
linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 2/4] mm: vmscan: Do not apply pressure to slab if we are not applying pressure to zone
Date: Sat, 25 Jun 2011 17:40:24 -0400 [thread overview]
Message-ID: <4E0655C8.7080908@redhat.com> (raw)
In-Reply-To: <1308926697-22475-3-git-send-email-mgorman@suse.de>
On 06/24/2011 10:44 AM, Mel Gorman wrote:
> During allocator-intensive workloads, kswapd will be woken frequently
> causing free memory to oscillate between the high and min watermark.
> This is expected behaviour.
>
> When kswapd applies pressure to zones during node balancing, it checks
> if the zone is above a high+balance_gap threshold. If it is, it does
> not apply pressure but it unconditionally shrinks slab on a global
> basis which is excessive. In the event kswapd is being kept awake due to
> a high small unreclaimable zone, it skips zone shrinking but still
> calls shrink_slab().
>
> Once pressure has been applied, the check for zone being unreclaimable
> is being made before the check is made if all_unreclaimable should be
> set. This miss of unreclaimable can cause has_under_min_watermark_zone
> to be set due to an unreclaimable zone preventing kswapd backing off
> on congestion_wait().
>
> Reported-and-tested-by: PA!draig Brady<P@draigBrady.com>
> Signed-off-by: Mel Gorman<mgorman@suse.de>
Acked-by: Rik van Riel <riel@redhat.com>
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next prev parent reply other threads:[~2011-06-25 21:40 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-06-24 14:44 [PATCH 0/4] Stop kswapd consuming 100% CPU when highest zone is small Mel Gorman
2011-06-24 14:44 ` [PATCH 1/4] mm: vmscan: Correct check for kswapd sleeping in sleeping_prematurely Mel Gorman
2011-06-25 21:33 ` Rik van Riel
2011-06-27 6:10 ` Minchan Kim
2011-06-28 21:49 ` Andrew Morton
2011-06-29 10:57 ` Pádraig Brady
2011-06-30 9:39 ` Mel Gorman
2011-06-30 2:23 ` KOSAKI Motohiro
2011-06-24 14:44 ` [PATCH 2/4] mm: vmscan: Do not apply pressure to slab if we are not applying pressure to zone Mel Gorman
2011-06-25 21:40 ` Rik van Riel [this message]
2011-06-28 23:38 ` Minchan Kim
2011-06-30 2:37 ` KOSAKI Motohiro
2011-06-24 14:44 ` [PATCH 3/4] mm: vmscan: Evaluate the watermarks against the correct classzone Mel Gorman
2011-06-25 21:42 ` Rik van Riel
2011-06-27 6:53 ` Minchan Kim
2011-06-28 12:52 ` Mel Gorman
2011-06-28 23:23 ` Minchan Kim
2011-06-28 23:23 ` Minchan Kim
2011-06-24 14:44 ` [PATCH 4/4] mm: vmscan: Only read new_classzone_idx from pgdat when reclaiming successfully Mel Gorman
2011-06-25 23:17 ` Rik van Riel
2011-06-30 9:05 ` KOSAKI Motohiro
2011-06-30 10:19 ` Mel Gorman
2011-07-19 16:09 ` Minchan Kim
2011-07-20 10:48 ` Mel Gorman
2011-07-21 15:30 ` Minchan Kim
2011-07-21 16:07 ` Mel Gorman
2011-07-21 16:36 ` Minchan Kim
2011-07-21 17:01 ` Mel Gorman
2011-07-22 0:21 ` Minchan Kim
2011-07-22 7:42 ` Mel Gorman
2011-06-25 14:23 ` [PATCH 0/4] Stop kswapd consuming 100% CPU when highest zone is small Andrew Lutomirski
2011-07-21 15:37 ` Minchan Kim
2011-07-21 16:09 ` Mel Gorman
2011-07-21 16:24 ` Minchan Kim
2011-07-21 16:36 ` Andrew Lutomirski
2011-07-21 16:42 ` Minchan Kim
2011-07-21 16:58 ` Andrew Lutomirski
2011-07-22 0:30 ` Minchan Kim
2011-07-22 13:21 ` Andrew Lutomirski
-- strict thread matches above, loose matches on Subject: below --
2011-06-24 13:43 Mel Gorman
2011-06-24 13:43 ` [PATCH 2/4] mm: vmscan: Do not apply pressure to slab if we are not applying pressure to zone Mel Gorman
2011-06-24 13:59 ` Mel Gorman
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