From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030868AbXDMWix (ORCPT ); Fri, 13 Apr 2007 18:38:53 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1030869AbXDMWix (ORCPT ); Fri, 13 Apr 2007 18:38:53 -0400 Received: from gprs189-60.eurotel.cz ([160.218.189.60]:37000 "EHLO amd.ucw.cz" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1030868AbXDMWiw (ORCPT ); Fri, 13 Apr 2007 18:38:52 -0400 Date: Sat, 14 Apr 2007 00:38:41 +0200 From: Pavel Machek To: Nigel Cunningham Cc: linux-pm@lists.osdl.org, Jiri Slaby , Linux kernel mailing list Subject: Re: [linux-pm] [RFD] swsusp problem: Drivers allocate much memory during suspend (was: Re: 2.6.21-rc5: swsusp: Not enough free memory) Message-ID: <20070413223841.GD28269@elf.ucw.cz> References: <460B6E4B.3060004@gmail.com> <200704131400.12021.rjw@sisk.pl> <1176466896.7112.159.camel@nigel.suspend2.net> <200704132241.52725.rjw@sisk.pl> <20070413221016.GQ28264@elf.ucw.cz> <1176503692.7112.189.camel@nigel.suspend2.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1176503692.7112.189.camel@nigel.suspend2.net> X-Warning: Reading this can be dangerous to your mental health. User-Agent: Mutt/1.5.11+cvs20060126 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hi! > > > > > Well, it looks like someone allocated about 6000 pages after we had freed > > > > > enough memory for suspending. > > > > > > > > We have a tunable allowance in Suspend2 for this, because fglrx > > > > allocates a lot of pages in its suspend routine if DRI is enabled. I > > > > think some other drivers do too, but fglrx is the main one I know. > > > > > > I wasn't aware of that, thanks for the information. > > > > > > I think this means we'll probably need to add a tunable, similar to image_size, > > > that will allow the users to specify how much spare memory they want to reserve > > > for suspending (instead of the constant PAGES_FOR_IO). IMO we can call it > > > 'spare_memory'. > > > > Just increase PAGES_FOR_IO. This should not be tunable. > > If we don't have a means for drivers to pre-allocate or say how much > memory they need, it should be tunable. Frankly, I'm startled that you > guys haven't heard of this issue before now. I can't believe everyone > who has ever wanted to hibernate with DRM enabled has been using > Suspend2. Maybe this is one of the sources of complaints that swsusp > isn't reliable? We do not support closed-source drivers, and open-source drivers are well behaved. > > > IMO to really fix the problem, we should let the drivers that need much memory > > > for suspending allocate it _before_ the memory shrinker is called. For this > > > purpose we can use notifiers that will be called before we start the shrinking > > > of memory. Namely, if a driver needs to allocate substantial amount > > > of memory > > > > Yes please. Using that notifier without leaking the memory will be > > "interesting" but if someone needs so much memory during suspend, let > > them eat their own complexity. > > It doesn't need to be that complex. Add another (optional) function to > the driver model to let drivers say how much they want and it becomes > trivial. Maybe this idea should be preferred over the notifier chain. Actually, it is trivial to prealocate during boot ;-). As the notifier chain can be useful for other stuff, too, I'd go that way. Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html