From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail191.messagelabs.com (mail191.messagelabs.com [216.82.242.19]) by kanga.kvack.org (Postfix) with SMTP id BB0A56B003D for ; Fri, 6 Feb 2009 03:04:02 -0500 (EST) Received: by ti-out-0910.google.com with SMTP id u3so892148tia.8 for ; Fri, 06 Feb 2009 00:04:00 -0800 (PST) Date: Fri, 6 Feb 2009 17:03:54 +0900 From: MinChan Kim 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> Sender: owner-linux-mm@kvack.org To: Johannes Weiner Cc: Andrew Morton , "Rafael J. Wysocki" , Rik van Riel , linux-kernel@vger.kernel.org, linux-mm@kvack.org List-ID: 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 -- 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