From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751227AbVIZLUh (ORCPT ); Mon, 26 Sep 2005 07:20:37 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751326AbVIZLUh (ORCPT ); Mon, 26 Sep 2005 07:20:37 -0400 Received: from gprs189-60.eurotel.cz ([160.218.189.60]:22465 "EHLO amd.ucw.cz") by vger.kernel.org with ESMTP id S1751227AbVIZLUg (ORCPT ); Mon, 26 Sep 2005 07:20:36 -0400 Date: Mon, 26 Sep 2005 13:20:22 +0200 From: Pavel Machek To: "Rafael J. Wysocki" Cc: LKML , Andrew Morton Subject: Re: [PATCH 3/3][Fix] swsusp: prevent swsusp from failing if there's too many pagedir pages Message-ID: <20050926112022.GD3554@elf.ucw.cz> References: <200509252018.36867.rjw@sisk.pl> <200509252044.00928.rjw@sisk.pl> <20050926103336.GA3693@elf.ucw.cz> <200509261311.29269.rjw@sisk.pl> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200509261311.29269.rjw@sisk.pl> X-Warning: Reading this can be dangerous to your mental health. User-Agent: Mutt/1.5.9i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hi! > > Lets see... > > > > for i386, we have 768 pagedir entries. Each pagedir entry points to > > page with 1023 pointers to pages. That means that up-to 768*1023*4096 > > bytes image can be saved to swap ~= 768 * 1K * 4K ~= 3 GB. That's more > > than enough for i386. > > > > for x86-64, we can have 128 pagedir entries (could not we fit more > > there? 384 entries should fit, no?). > > Yes. To be exact, 460. > > > Each pagedir entry has 511 pointers to pages (IIRC)... > > 512, I think. Okay, can we do simple solution where we put 460 there, plus a check if it overflows (printk, abort suspend), for now? That should fix 768MB machine... > > that is up-to 128*511*4K ~= 64*1K*4K = 256 MB image. > > Hmm, that should still be enough for any 512MB machine, and > > probably okay for much bigger machines, too... > > > > We can still get to 768 MB image (good enough for any 1.5GB machine, > > and probably for anything else, too). > > > > If that is not good enough for you, can you simply allocate more than > > 1 page for swsusp_info? No need for linklists yet. > > I can. The problem is I have to track the swap offsets of these pages > which is necessary for resume. Is it guaranteed that the swap offsets > of pages allocated in a row will be consecutive? No, they probably will not be consecutive. OTOH pagedirs are stored as a link list in memory already. Maybe we should be able to extend that link list for a disk, too, with minimal fuss? ...we'd have to write pagedir _backwards_ for that to work, probably not nice, and swap_free() would really like direct access. Pavel -- if you have sharp zaurus hardware you don't need... you know my address