From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail190.messagelabs.com (mail190.messagelabs.com [216.82.249.51]) by kanga.kvack.org (Postfix) with SMTP id D9E8F6B0044 for ; Tue, 3 Nov 2009 16:11:12 -0500 (EST) Message-ID: <4AF09CB2.9030500@crca.org.au> Date: Wed, 04 Nov 2009 08:12:18 +1100 From: Nigel Cunningham MIME-Version: 1.0 Subject: Re: [PATCHv2 2/5] vmscan: Kill hibernation specific reclaim logic and unify it References: <20091102000855.F404.A69D9226@jp.fujitsu.com> <20091103002520.886C.A69D9226@jp.fujitsu.com> <4AEF4CF1.3020500@crca.org.au> <200911031230.20344.rjw@sisk.pl> In-Reply-To: <200911031230.20344.rjw@sisk.pl> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: "Rafael J. Wysocki" Cc: KOSAKI Motohiro , LKML , Rik van Riel , linux-mm , Andrew Morton List-ID: Hi Rafael. Rafael J. Wysocki wrote: > On Monday 02 November 2009, Nigel Cunningham wrote: >> Hi. > > Hi, > >> KOSAKI Motohiro wrote: >>>> I haven't given much thought to numa awareness in hibernate code, but I >>>> can say that the shrink_all_memory interface is woefully inadequate as >>>> far as zone awareness goes. Since lowmem needs to be atomically restored >>>> before we can restore highmem, we really need to be able to ask for a >>>> particular number of pages of a particular zone type to be freed. >>> Honestly, I am not suspend/hibernation expert. Can I ask why caller need to know >>> per-zone number of freed pages information? if hibernation don't need highmem. >>> following incremental patch prevent highmem reclaim perfectly. Is it enough? >> (Disclaimer: I don't think about highmem a lot any more, and might have >> forgotten some of the details, or swsusp's algorithms might have >> changed. Rafael might need to correct some of this...) >> >> Imagine that you have a system with 1000 pages of lowmem and 5000 pages >> of highmem. Of these, 950 lowmem pages are in use and 500 highmem pages >> are in use. >> >> In order to to be able to save an image, we need to be able to do an >> atomic copy of those lowmem pages. >> >> You might think that we could just copy everything into the spare >> highmem pages, but we can't because mapping and unmapping the highmem >> pages as we copy the data will leave us with an inconsistent copy. > > This isn't the case any more for the mainline hibernate code. We use highmem > for storing image data as well as lowmem. Highmem for storing copies of lowmem pages? Regards, Nigel -- 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