From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Fri, 7 Nov 2008 10:42:42 +0000 From: Mel Gorman Subject: Re: [RFC][PATCH] mm: the page of MIGRATE_RESERVE don't insert into pcp Message-ID: <20081107104242.GC13786@csn.ul.ie> References: <20081106091431.0D2A.KOSAKI.MOTOHIRO@jp.fujitsu.com> <20081106164644.GA14012@csn.ul.ie> <20081107104224.1631057e.kamezawa.hiroyu@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <20081107104224.1631057e.kamezawa.hiroyu@jp.fujitsu.com> Sender: owner-linux-mm@kvack.org Return-Path: To: KAMEZAWA Hiroyuki Cc: KOSAKI Motohiro , LKML , Christoph Lameter , linux-mm List-ID: On Fri, Nov 07, 2008 at 10:42:24AM +0900, KAMEZAWA Hiroyuki wrote: > On Thu, 6 Nov 2008 16:46:45 +0000 > Mel Gorman wrote: > > > otherwise, the system have unnecessary memory starvation risk > > > because other cpu can't use this emergency pages. > > > > > > > > > > > > Signed-off-by: KOSAKI Motohiro > > > CC: Mel Gorman > > > CC: Christoph Lameter > > > > > > > This patch seems functionally sound but as Christoph points out, this > > adds another branch to the fast path. Now, I ran some tests and those that > > completed didn't show any problems but adding branches in the fast path can > > eventually lead to hard-to-detect performance problems. > > > dividing pcp-list into MIGRATE_TYPES is bad ? I do not understand what your question is. > If divided, we can get rid of scan. > I don't know what you are saying here either. I think you are saying that we should avoid scanning the PCP lists for migrate types at all. That hurts anti-fragmentation as pages can be badly placed if any pcp page is used. -- Mel Gorman Part-time Phd Student Linux Technology Center University of Limerick IBM Dublin Software Lab -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org