From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2992714AbXCGWtf (ORCPT ); Wed, 7 Mar 2007 17:49:35 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S2992766AbXCGWte (ORCPT ); Wed, 7 Mar 2007 17:49:34 -0500 Received: from smtp.osdl.org ([65.172.181.24]:35872 "EHLO smtp.osdl.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2992758AbXCGWtc (ORCPT ); Wed, 7 Mar 2007 17:49:32 -0500 Date: Wed, 7 Mar 2007 14:49:03 -0800 From: Andrew Morton To: "Rafael J. Wysocki" Cc: LKML , Pavel Machek Subject: Re: [PATCH] swsusp: Disable nonboot CPUs before entering platform suspend Message-Id: <20070307144903.6e196b88.akpm@linux-foundation.org> In-Reply-To: <200703072314.30265.rjw@sisk.pl> References: <200703072044.12021.rjw@sisk.pl> <20070307131618.308d46e6.akpm@linux-foundation.org> <200703072314.30265.rjw@sisk.pl> X-Mailer: Sylpheed version 2.2.7 (GTK+ 2.8.6; i686-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 7 Mar 2007 23:14:29 +0100 "Rafael J. Wysocki" wrote: > On Wednesday, 7 March 2007 22:16, Andrew Morton wrote: > > On Wed, 7 Mar 2007 20:44:11 +0100 > > "Rafael J. Wysocki" wrote: > > > > > From: Rafael J. Wysocki > > > > > > Prevent the WARN_ON() in arch/x86_64/kernel/acpi/sleep.c:init_low_mapping() > > > from triggering by disabling nonboot CPUs before we finally enter the platform > > > suspend. > > > > > > Signed-off-by: Rafael J. Wysocki > > > --- > > > kernel/power/disk.c | 1 + > > > kernel/power/user.c | 2 +- > > > 2 files changed, 2 insertions(+), 1 deletion(-) > > > > > > Index: linux-2.6.21-rc2-mm2/kernel/power/disk.c > > > =================================================================== > > > --- linux-2.6.21-rc2-mm2.orig/kernel/power/disk.c > > > +++ linux-2.6.21-rc2-mm2/kernel/power/disk.c > > > @@ -61,6 +61,7 @@ static void power_down(suspend_disk_meth > > > switch(mode) { > > > case PM_DISK_PLATFORM: > > > if (pm_ops && pm_ops->enter) { > > > + disable_nonboot_cpus(); > > > kernel_shutdown_prepare(SYSTEM_SUSPEND_DISK); > > > pm_ops->enter(PM_SUSPEND_DISK); > > > break; > > > Index: linux-2.6.21-rc2-mm2/kernel/power/user.c > > > =================================================================== > > > --- linux-2.6.21-rc2-mm2.orig/kernel/power/user.c > > > +++ linux-2.6.21-rc2-mm2/kernel/power/user.c > > > @@ -398,9 +398,9 @@ static int snapshot_ioctl(struct inode * > > > > > > case PMOPS_ENTER: > > > if (data->platform_suspend) { > > > + disable_nonboot_cpus(); > > > kernel_shutdown_prepare(SYSTEM_SUSPEND_DISK); > > > error = pm_ops->enter(PM_SUSPEND_DISK); > > > - error = 0; > > > } > > > break; > > > > Is this considered 2.6.21 material? If so why? > > Well, the WARN_ON() in arch/x86_64/kernel/acpi/sleep.c:init_low_mapping() > triggers every time an SMP x86_64 box is suspended to disk using the platform > mode (default), which is quite annoying IMHO and users think something wrong is > going on. This will probably cause them to report the problem and I'd rather > like to avoid handling these reports. ;-) Well sure - if patches were always error-free, we'd always apply them immediately. The question is: is the risk of this patch breaking things exceeded by the benefit which you describe?