From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail138.messagelabs.com (mail138.messagelabs.com [216.82.249.35]) by kanga.kvack.org (Postfix) with SMTP id A188860021B for ; Fri, 4 Dec 2009 00:19:23 -0500 (EST) Received: from m2.gw.fujitsu.co.jp ([10.0.50.72]) by fgwmail6.fujitsu.co.jp (Fujitsu Gateway) with ESMTP id nB45JKFS006344 for (envelope-from kamezawa.hiroyu@jp.fujitsu.com); Fri, 4 Dec 2009 14:19:20 +0900 Received: from smail (m2 [127.0.0.1]) by outgoing.m2.gw.fujitsu.co.jp (Postfix) with ESMTP id 44E5945DE64 for ; Fri, 4 Dec 2009 14:19:20 +0900 (JST) Received: from s2.gw.fujitsu.co.jp (s2.gw.fujitsu.co.jp [10.0.50.92]) by m2.gw.fujitsu.co.jp (Postfix) with ESMTP id 197AC45DE55 for ; Fri, 4 Dec 2009 14:19:20 +0900 (JST) Received: from s2.gw.fujitsu.co.jp (localhost.localdomain [127.0.0.1]) by s2.gw.fujitsu.co.jp (Postfix) with ESMTP id EE05E1DB803A for ; Fri, 4 Dec 2009 14:19:19 +0900 (JST) Received: from m106.s.css.fujitsu.com (m106.s.css.fujitsu.com [10.249.87.106]) by s2.gw.fujitsu.co.jp (Postfix) with ESMTP id 8FE50E78001 for ; Fri, 4 Dec 2009 14:19:19 +0900 (JST) Date: Fri, 4 Dec 2009 14:16:17 +0900 From: KAMEZAWA Hiroyuki Subject: Re: [PATCH 2/9] ksm: let shared pages be swappable Message-Id: <20091204141617.f4c491e7.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: <20091204135938.5886.A69D9226@jp.fujitsu.com> References: <20091202125501.GD28697@random.random> <20091203134610.586E.A69D9226@jp.fujitsu.com> <20091204135938.5886.A69D9226@jp.fujitsu.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: KOSAKI Motohiro Cc: Andrea Arcangeli , Rik van Riel , Hugh Dickins , Andrew Morton , Izik Eidus , Chris Wright , linux-kernel@vger.kernel.org, linux-mm@kvack.org List-ID: On Fri, 4 Dec 2009 14:06:07 +0900 (JST) KOSAKI Motohiro wrote: > > Umm?? Personally I don't like knob. If you have problematic workload, > > please tell it us. I will try to make reproduce environment on my box. > > If current code doesn't works on KVM or something-else, I really want > > to fix it. > > > > I think Larry's trylock idea and your 64 young bit idea can be combinate. > > I only oppose the page move to inactive list without clear young bit. IOW, > > if VM pressure is very low and the page have lots young bit, the page should > > go back active list although trylock(ptelock) isn't contended. > > > > But unfortunatelly I don't have problem workload as you mentioned. Anyway > > we need evaluate way to your idea. We obviouslly more info. > > [Off topic start] > > Windows kernel have zero page thread and it clear the pages in free list > periodically. because many windows subsystem prerefer zero filled page. > hen, if we use windows guest, zero filled page have plenty mapcount rather > than other typical sharing pages, I guess. > > So, can we mark as unevictable to zero filled ksm page? > Hmm, can't we use ZERO_PAGE we have now ? If do so, - no mapcount check - never on LRU - don't have to maintain shared information because ZERO_PAGE itself has copy-on-write nature. Thanks, -Kame -- 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