From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail202.messagelabs.com (mail202.messagelabs.com [216.82.254.227]) by kanga.kvack.org (Postfix) with SMTP id 1FBCF6B006A for ; Thu, 14 Jan 2010 03:32:49 -0500 (EST) Date: Thu, 14 Jan 2010 16:32:29 +0800 From: Wu Fengguang Subject: Re: [resend][PATCH] mm: Restore zone->all_unreclaimable to independence word Message-ID: <20100114083229.GA7860@localhost> References: <20100114103332.D71B.A69D9226@jp.fujitsu.com> <20100114161311.673B.A69D9226@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20100114161311.673B.A69D9226@jp.fujitsu.com> Sender: owner-linux-mm@kvack.org To: KOSAKI Motohiro Cc: David Rientjes , LKML , linux-mm , Andrew Morton , KAMEZAWA Hiroyuki , Minchan Kim , Huang Shijie List-ID: On Thu, Jan 14, 2010 at 03:14:10PM +0800, KOSAKI Motohiro wrote: > > On Thu, 14 Jan 2010, KOSAKI Motohiro wrote: > > > > > commit e815af95 (change all_unreclaimable zone member to flags) chage > > > all_unreclaimable member to bit flag. but It have undesireble side > > > effect. > > > free_one_page() is one of most hot path in linux kernel and increasing > > > atomic ops in it can reduce kernel performance a bit. > > > > > > Thus, this patch revert such commit partially. at least > > > all_unreclaimable shouldn't share memory word with other zone flags. > > > > > > > I still think you need to quantify this; saying you don't have a large > > enough of a machine that will benefit from it isn't really a rationale for > > the lack of any data supporting your claim. We should be basing VM > > changes on data, not on speculation that there's a measurable impact > > here. > > > > Perhaps you could ask a colleague or another hacker to run a benchmark for > > you so that the changelog is complete? > > ok, fair. although I dislike current unnecessary atomic-ops. > I'll pending this patch until get good data. I think it's a reasonable expectation to help large boxes. What we can do now, is to measure if it hurts mainline SMP boxes. If not, we are set on doing the patch :) Thanks, Fengguang -- 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