From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751523AbXDHQ7J (ORCPT ); Sun, 8 Apr 2007 12:59:09 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751536AbXDHQ7J (ORCPT ); Sun, 8 Apr 2007 12:59:09 -0400 Received: from ogre.sisk.pl ([217.79.144.158]:51789 "EHLO ogre.sisk.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751523AbXDHQ7G (ORCPT ); Sun, 8 Apr 2007 12:59:06 -0400 From: "Rafael J. Wysocki" To: Pavel Machek Subject: Re: [RFC][PATCH -mm] swsusp: Use rbtree for tracking allocated swap Date: Sun, 8 Apr 2007 19:02:35 +0200 User-Agent: KMail/1.9.5 Cc: LKML , Andrew Morton , Nigel Cunningham References: <200704072320.40238.rjw@sisk.pl> <20070408125636.GB4404@ucw.cz> In-Reply-To: <20070408125636.GB4404@ucw.cz> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200704081902.35857.rjw@sisk.pl> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Sunday, 8 April 2007 14:56, Pavel Machek wrote: > Hi! > > > Some time ago we discussed the possibility of simplifying the swsusp's approach > > towards tracking the swap pages allocated by it for saving the image (so that > > they can be freed if there's an error). > > > > I think we can get back to it now, as it is a nice optimization that should > > allow us to use less memory (almost always) and improve performance a bit. > > > > Well, I do not think you can measure the difference, but... As far as the memory usage is concerned, I can. :-) Usually, it takes 1 extent (40 B on x86_64) to register all of the allocated swap pages. If bitmaps are used, we need as many bits as there are swap pages available (for 1 GB swap and 4 KB pages that would be ~250000 bits, which gives ~8 pages, and we can save more than 800 extents using that much memory). > > kernel/power/power.h | 27 +--------- > > kernel/power/swap.c | 18 +----- > > kernel/power/swsusp.c | 135 ++++++++++++++++++++++++++------------------------ > > kernel/power/user.c | 22 +------- > > 4 files changed, 85 insertions(+), 117 deletions(-) > > ....as it removes code... I think we can do that. But it is 2.6.23+ > material. Yes, I think so, but still we can ask Andrew to include it into -mm earlier? ;-) Rafael