From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail137.messagelabs.com (mail137.messagelabs.com [216.82.249.19]) by kanga.kvack.org (Postfix) with SMTP id C78396B003D for ; Fri, 4 Dec 2009 12:16:45 -0500 (EST) Date: Fri, 4 Dec 2009 09:16:40 -0800 From: Chris Wright Subject: Re: [PATCH 2/9] ksm: let shared pages be swappable Message-ID: <20091204171640.GE19624@x200.localdomain> References: <20091202125501.GD28697@random.random> <20091203134610.586E.A69D9226@jp.fujitsu.com> <20091204135938.5886.A69D9226@jp.fujitsu.com> <20091204141617.f4c491e7.kamezawa.hiroyu@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20091204141617.f4c491e7.kamezawa.hiroyu@jp.fujitsu.com> Sender: owner-linux-mm@kvack.org To: KAMEZAWA Hiroyuki Cc: KOSAKI Motohiro , Andrea Arcangeli , Rik van Riel , Hugh Dickins , Andrew Morton , Izik Eidus , Chris Wright , linux-kernel@vger.kernel.org, linux-mm@kvack.org List-ID: * KAMEZAWA Hiroyuki (kamezawa.hiroyu@jp.fujitsu.com) wrote: > KOSAKI Motohiro wrote: > > 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? That's why I mentioned the page of zeroes as the prime example of something with a high mapcount that shouldn't really ever be evicted. > 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. It's a somewhat special case, but wouldn't it be useful to have a generic method to recognize this kind of sharing since it's a generic issue? thanks, -chris -- 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