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

From: Balbir Singh
Date: Thu Sep 23 2010 - 07:44:51 EST


* KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx> [2010-09-16 19:01:32]:

> + if (!(zone_reclaim_mode & RECLAIM_CACHE) &&
> + (gfp_mask & GFP_MOVABLE_MASK) == GFP_MOVABLE_MASK) {
> + inc_zone_state(zone, NR_ZONE_CACHE_AVOID);
> + goto try_next_zone;
> + }
> +

Interesting approach, so for page cache related applications we expect
RECLAIM_CACHE to be set and hence zone_reclaim to occur. I have
another variation, a new gfp flag called __GFP_FREE_CACHE. You can
find the patches at

http://lwn.net/Articles/391293/
http://article.gmane.org/gmane.linux.kernel.mm/49155

--
Three Cheers,
Balbir
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