netdev - [PATCH 3/5] vmscan: Force kswapd to take notice faster when high-order watermarks are being hit

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Thu, 22 Oct 2009 15:22:34 +0100
From:	Mel Gorman <mel@....ul.ie>
To:	Frans Pop <elendil@...net.nl>, Jiri Kosina <jkosina@...e.cz>,
	Sven Geggus <lists@...hsschwanzdomain.de>,
	Karol Lewandowski <karol.k.lewandowski@...il.com>,
	Tobias Oetiker <tobi@...iker.ch>
Cc:	"Rafael J. Wysocki" <rjw@...k.pl>,
	David Miller <davem@...emloft.net>,
	Reinette Chatre <reinette.chatre@...el.com>,
	Kalle Valo <kalle.valo@....fi>,
	David Rientjes <rientjes@...gle.com>,
	KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>,
	Mohamed Abbas <mohamed.abbas@...el.com>,
	Jens Axboe <jens.axboe@...cle.com>,
	"John W. Linville" <linville@...driver.com>,
	Pekka Enberg <penberg@...helsinki.fi>,
	Bartlomiej Zolnierkiewicz <bzolnier@...il.com>,
	Greg Kroah-Hartman <gregkh@...e.de>,
	Stephan von Krawczynski <skraw@...net.com>,
	Kernel Testers List <kernel-testers@...r.kernel.org>,
	netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
	"linux-mm@...ck.org\"" <linux-mm@...ck.org>,
	Mel Gorman <mel@....ul.ie>
Subject: [PATCH 3/5] vmscan: Force kswapd to take notice faster when high-order watermarks are being hit

When a high-order allocation fails, kswapd is kicked so that it reclaims
at a higher-order to avoid direct reclaimers stall and to help GFP_ATOMIC
allocations. Something has changed in recent kernels that affect the timing
where high-order GFP_ATOMIC allocations are now failing with more frequency,
particularly under pressure. This patch forces kswapd to notice sooner that
high-order allocations are occuring.

Signed-off-by: Mel Gorman <mel@....ul.ie>
---
 mm/vmscan.c |    9 +++++++++
 1 files changed, 9 insertions(+), 0 deletions(-)

diff --git a/mm/vmscan.c b/mm/vmscan.c
index 64e4388..cd68109 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -2016,6 +2016,15 @@ loop_again:
 					priority != DEF_PRIORITY)
 				continue;
 
+			/*
+			 * Exit quickly to restart if it has been indicated
+			 * that higher orders are required
+			 */
+			if (pgdat->kswapd_max_order > order) {
+				all_zones_ok = 1;
+				goto out;
+			}
+
 			if (!zone_watermark_ok(zone, order,
 					high_wmark_pages(zone), end_zone, 0))
 				all_zones_ok = 0;
-- 
1.6.3.3

--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html