On Mon, 25 Oct 2010 12:24:24 +0900 (JST) KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx> wrote: > Recently, Robert Mueller reported zone_reclaim_mode doesn't work > properly on his new NUMA server (Dual Xeon E5520 + Intel S5520UR MB). > He is using Cyrus IMAPd and it's built on a very traditional > single-process model. > > * a master process which reads config files and manages the other > process > * multiple imapd processes, one per connection > * multiple pop3d processes, one per connection > * multiple lmtpd processes, one per connection > * periodical "cleanup" processes. > > Then, there are thousands of independent processes. The problem is, > recent Intel motherboard turn on zone_reclaim_mode by default and > traditional prefork model software don't work fine on it. > Unfortunatelly, Such model is still typical one even though 21th > century. We can't ignore them. > > This patch raise zone_reclaim_mode threshold to 30. 30 don't have > specific meaning. but 20 mean one-hop QPI/Hypertransport and such > relatively cheap 2-4 socket machine are often used for tradiotional > server as above. The intention is, their machine don't use > zone_reclaim_mode. > > Note: ia64 and Power have arch specific RECLAIM_DISTANCE definition. > then this patch doesn't change such high-end NUMA machine behavior. > > Cc: Mel Gorman <mel@xxxxxxxxx> > Cc: Bron Gondwana <brong@xxxxxxxxxxx> > Cc: Robert Mueller <robm@xxxxxxxxxxx> > Acked-by: Christoph Lameter <cl@xxxxxxxxx> > Acked-by: David Rientjes <rientjes@xxxxxxxxxx> > Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>