Re: [PATCH] vmscan: Stop kswapd waiting on congestion when the min watermark is not being met V2

Tobias Oetiker
2009-11-26T14:45:22Z

Hi Mel,

Nov 13 Mel Gorman wrote:

> The last version has a stupid bug in it. Sorry.
>
> Changelog since V1
> o Fix incorrect negation
> o Rename kswapd_no_congestion_wait to kswapd_skip_congestion_wait as
> suggested by Rik
>
> If reclaim fails to make sufficient progress, the priority is raised.
> Once the priority is higher, kswapd starts waiting on congestion. However,
> if the zone is below the min watermark then kswapd needs to continue working
> without delay as there is a danger of an increased rate of GFP_ATOMIC
> allocation failure.
>
> This patch changes the conditions under which kswapd waits on
> congestion by only going to sleep if the min watermarks are being met.

I finally got around to test this together with the whole series on
2.6.31.6. after running it for a day I have not yet seen a single
order:5 allocation problem ... (while I had several an hour before)

for the record, my kernel is now running with the following
patches:

patch1:Date: Thu, 12 Nov 2009 19:30:31 +0000
patch1:Subject: [PATCH 1/5] page allocator: Always wake kswapd when restarting an allocation attempt after direct reclaim failed

patch2:Date: Thu, 12 Nov 2009 19:30:32 +0000
patch2:Subject: [PATCH 2/5] page allocator: Do not allow interrupts to use ALLOC_HARDER

patch3:Date: Thu, 12 Nov 2009 19:30:33 +0000
patch3:Subject: [PATCH 3/5] page allocator: Wait on both sync and async congestion after direct reclaim

patch4:Date: Thu, 12 Nov 2009 19:30:34 +0000
patch4:Subject: [PATCH 4/5] vmscan: Have kswapd sleep for a short interval and double check it should be asleep

patch5:Date: Fri, 13 Nov 2009 20:03:57 +0000
patch5:Subject: [PATCH] vmscan: Stop kswapd waiting on congestion when the min watermark is not being met V2

patch6:Date: Tue, 17 Nov 2009 10:34:21 +0000
patch6:Subject: [PATCH] vmscan: Have kswapd sleep for a short interval and double check it should be asleep fix 1

cheers
tobi

--
Tobi Oetiker, OETIKER+PARTNER AG, Aarweg 15 CH-4600 Olten, Switzerland
http://it.oetiker.ch tobi@oetiker.ch ++41 62 775 9902 / sb: -9900