From mboxrd@z Thu Jan 1 00:00:00 1970 From: Robin Holt Date: Thu, 04 Jun 2009 12:24:09 +0000 Subject: Re: [PATCH v4] zone_reclaim is always 0 by default Message-Id: <20090604122409.GK29447@sgi.com> List-Id: References: <20090604192236.9761.A69D9226@jp.fujitsu.com> In-Reply-To: <20090604192236.9761.A69D9226@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: KOSAKI Motohiro Cc: Christoph Lameter , Rik van Riel , Robin Holt , "Zhang, Yanmin" , Wu Fengguang , linux-ia64@vger.kernel.org, linuxppc-dev@ozlabs.org, LKML , linux-mm , Andrew Morton Acked-by: Robin Holt On Thu, Jun 04, 2009 at 07:23:15PM +0900, KOSAKI Motohiro wrote: ... > Actually, zone_reclaim_mode=1 mean "I dislike remote node allocation rather than > disk access", it makes performance improvement to HPC workload. > but it makes performance degression to desktop, file server and web server. I still disagree with this statement, but I don't care that much. Why not something more to the effect of: Setting zone_reclaim_mode=1 causes memory allocations on a nearly exhausted node to do direct reclaim within that node before attempting off-node allocations. For work loads where most pages are clean in page cache and easily reclaimed, this can result excessive disk activity versus a more fair node memory balance. If you disagree, don't respond, just ignore. ... > --- a/include/linux/topology.h > +++ b/include/linux/topology.h > @@ -54,12 +54,7 @@ int arch_update_cpu_topology(void); > #define node_distance(from,to) ((from) = (to) ? LOCAL_DISTANCE : REMOTE_DISTANCE) > #endif > #ifndef RECLAIM_DISTANCE > -/* > - * If the distance between nodes in a system is larger than RECLAIM_DISTANCE > - * (in whatever arch specific measurement units returned by node_distance()) > - * then switch on zone reclaim on boot. > - */ > -#define RECLAIM_DISTANCE 20 > +#define RECLAIM_DISTANCE INT_MAX Why remove this comment? It seems more-or-less a reasonable statement. Thanks, Robin