From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757264AbZBFIEU (ORCPT ); Fri, 6 Feb 2009 03:04:20 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752553AbZBFIEF (ORCPT ); Fri, 6 Feb 2009 03:04:05 -0500 Received: from ti-out-0910.google.com ([209.85.142.187]:52809 "EHLO ti-out-0910.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752545AbZBFIED (ORCPT ); Fri, 6 Feb 2009 03:04:03 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=date:from:to:cc:subject:message-id:references:mime-version :content-type:content-disposition:in-reply-to:user-agent; b=VnMx1NhRDN6Wv6rAVZbDyhDny+1PFOZsdvNg7dj8Jh7I1B01Q8XSMwPnT4xhiohCbN PVd58OyQ+3kbBB2Y9pqqDWrGHprhlQAtmnKY8+5btp8rXhK9OK+lDhJiBDMshZajpVJM hyqfGcDbbCo3HYmgrNi0lU/cqhA4Mo8F5Ko+s= Date: Fri, 6 Feb 2009 17:03:54 +0900 From: MinChan Kim To: Johannes Weiner Cc: Andrew Morton , "Rafael J. Wysocki" , Rik van Riel , linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH 3/3][RFC] swsusp: shrink file cache first Message-ID: <20090206080354.GA6516@barrios-desktop> References: <20090206031125.693559239@cmpxchg.org> <20090206031324.004715023@cmpxchg.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090206031324.004715023@cmpxchg.org> User-Agent: Mutt/1.5.17+20080114 (2008-01-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, Johannes. I have some questions. Just out of curiosity. :) On Fri, Feb 06, 2009 at 04:11:28AM +0100, Johannes Weiner wrote: > File cache pages are saved to disk either through normal writeback by > reclaim or by including them in the suspend image written to a > swapfile. > > Writing them either way should take the same amount of time but doing > normal writeback and unmap changes the fault behaviour on resume from > prefault to on-demand paging, smoothening out resume and giving What do you mean "unmap"? Why normal writeback and unmap chnages the fault behavior on resume ? > previously cached pages the chance to stay out of memory completely if > they are not used anymore. > > Another reason for preferring file page eviction is that the locality > principle is visible in fault patterns and swap might perform really > bad with subsequent faulting of contiguously mapped pages. Why do you think that swap might perform bad with subsequent faulting of contiguusly mapped page ? You mean normal file system is faster than swap due to readahead and smart block of allocation ? -- Kinds Regards MinChan Kim