Re: Default zone_reclaim_mode = 1 on NUMA kernel is bad forfile/email/web servers

From: KAMEZAWA Hiroyuki
Date: Mon Sep 20 2010 - 21:10:38 EST


On Thu, 16 Sep 2010 19:01:32 +0900 (JST)
KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx> wrote:

> Yes, sadly intel motherboard turn on zone_reclaim_mode by default. and
> current zone_reclaim_mode doesn't fit file/web server usecase ;-)
>
> So, I've created new proof concept patch. This doesn't disable zone_reclaim
> at all. Instead, distinguish for file cache and for anon allocation and
> only file cache doesn't use zone-reclaim.
>
> That said, high-end hpc user often turn on cpuset.memory_spread_page and
> they avoid this issue. But, why don't we consider avoid it by default?
>
>
> Rob, I wonder if following patch help you. Could you please try it?
>
>
> Subject: [RFC] vmscan: file cache doesn't use zone_reclaim by default
>

Hm, can't we use migration of file caches rather than pageout in
zone_reclaim_mode ? Doent' it fix anything ?

Thanks,
-Kame

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