From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756611AbYKKONN (ORCPT ); Tue, 11 Nov 2008 09:13:13 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755944AbYKKOM4 (ORCPT ); Tue, 11 Nov 2008 09:12:56 -0500 Received: from ogre.sisk.pl ([217.79.144.158]:53508 "EHLO ogre.sisk.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755943AbYKKOM4 (ORCPT ); Tue, 11 Nov 2008 09:12:56 -0500 From: "Rafael J. Wysocki" To: Pavel Machek Subject: Re: CONFIG_NUMA breaks hibernation on x86-32 with PAE Date: Tue, 11 Nov 2008 15:17:53 +0100 User-Agent: KMail/1.9.9 Cc: Andi Kleen , Ingo Molnar , kernel list , "H. Peter Anvin" References: <20081109140726.GB1786@ucw.cz> <200811101928.04565.rjw@sisk.pl> <20081111103043.GD5464@elf.ucw.cz> In-Reply-To: <20081111103043.GD5464@elf.ucw.cz> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200811111517.54470.rjw@sisk.pl> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tuesday, 11 of November 2008, Pavel Machek wrote: > On Mon 2008-11-10 19:28:03, Rafael J. Wysocki wrote: > > On Monday, 10 of November 2008, Andi Kleen wrote: > > > Ingo Molnar writes: > > > > > > > > No good ideas - the bug description gives me the impression of memory > > > > maps save/restore hickup in the hibernation code - and memory maps are > > > > pretty much the only thing that are significantly different on NUMA. > > > > > > I assume the problem happened on a single node system. > > > On single node the memory map should be actually quite similar > > > to the UMA case. > > > > It is. However, the problem is 100% reproducible on any 32-bit single-node > > system with CONFIG_NUMA set, from what I can tell. > > > > It doesn't happen if the kernel is booted with highmem=0, so it looks like > > the code that saves highmem causes the problem to happen. However, this > > same code works well for all of the !CONFIG_NUMA cases and practically only > > the only non-open-coded it uses is kmap_atomic(). > > kmap_atomic() and kernel_map_pages(), AFAICT. > > Can kmap_atomic() modify pages in highmem, too? > > Wait... are we putting kernel pagetables in the high memory? > > What about this cleanup (warning: untested) Yes, I have this queued up and actually tested. Thanks, Rafael > diff --git a/kernel/power/snapshot.c b/kernel/power/snapshot.c > index 5d2ab83..f1d8336 100644 > --- a/kernel/power/snapshot.c > +++ b/kernel/power/snapshot.c > @@ -966,7 +966,7 @@ static void copy_data_page(unsigned long > * data modified by kmap_atomic() > */ > safe_copy_page(buffer, s_page); > - dst = kmap_atomic(pfn_to_page(dst_pfn), KM_USER0); > + dst = kmap_atomic(d_page, KM_USER0); > memcpy(dst, buffer, PAGE_SIZE); > kunmap_atomic(dst, KM_USER0); > } else { > > Pavel -- Everyone knows that debugging is twice as hard as writing a program in the first place. So if you're as clever as you can be when you write it, how will you ever debug it? --- Brian Kernighan