From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pavel Machek Subject: Re: [RFD] swsusp problem: Drivers allocate much memory during suspend (was: Re: 2.6.21-rc5: swsusp: Not enough free memory) Date: Sat, 14 Apr 2007 00:38:41 +0200 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="iso-8859-1" Content-Transfer-Encoding: quoted-printable Return-path: Content-Disposition: inline In-Reply-To: <1176503692.7112.189.camel@nigel.suspend2.net> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linux-pm-bounces@lists.linux-foundation.org Errors-To: linux-pm-bounces@lists.linux-foundation.org To: Nigel Cunningham Cc: linux-pm@lists.osdl.org, Jiri Slaby , Linux kernel mailing list List-Id: linux-pm@vger.kernel.org Hi! > > > > > Well, it looks like someone allocated about 6000 pages after we h= ad 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 i= mage_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 ca= ll 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 mu= ch memory > > > for suspending allocate it _before_ the memory shrinker is called. F= or 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/blo= g.html