Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754606AbcDFXx6 (ORCPT ); Wed, 6 Apr 2016 19:53:58 -0400 Received: from mail.kernel.org ([198.145.29.136]:54988 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753469AbcDFXx5 (ORCPT ); Wed, 6 Apr 2016 19:53:57 -0400 Date: Wed, 6 Apr 2016 16:53:54 -0700 (PDT) From: Stefano Stabellini X-X-Sender: sstabellini@sstabellini-ThinkPad-X230 To: David Vrabel cc: Anna-Maria Gleixner , linux-kernel@vger.kernel.org, xen-devel@lists.xenproject.org, Stefano Stabellini , rt@linutronix.de, David Vrabel Subject: Re: [Xen-devel] [PATCH] xen: Add comment for missing FROZEN notifier transitions In-Reply-To: <57050A98.80901@cantab.net> Message-ID: References: <1459773140-43707-1-git-send-email-anna-maria@linutronix.de> <57050A98.80901@cantab.net> User-Agent: Alpine 2.10 (DEB 1266 2009-07-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1302 Lines: 33 On Wed, 6 Apr 2016, David Vrabel wrote: > On 04/04/16 13:32, Anna-Maria Gleixner wrote: > > Xen guests do not offline/online CPUs during suspend/resume and > > therefore FROZEN notifier transitions are not required. Add this > > explanation as a comment in the code to get not confused why > > CPU_TASKS_FROZEN masked transitions are not considered. > > > > Cc: David Vrabel > > Cc: Stefano Stabellini > > Cc: xen-devel@lists.xenproject.org > > Signed-off-by: Anna-Maria Gleixner > > --- > > arch/arm/xen/enlighten.c | 6 ++++++ > > arch/x86/xen/enlighten.c | 7 +++++++ > > drivers/xen/events/events_fifo.c | 6 ++++++ > > 3 files changed, 19 insertions(+) > > > > --- a/arch/arm/xen/enlighten.c > > +++ b/arch/arm/xen/enlighten.c > > @@ -213,6 +213,12 @@ static int xen_cpu_notification(struct n > > unsigned long action, > > void *hcpu) > > { > > + /* > > + * Xen guests do not offline/online CPUs during > > + * suspend/resume, thus CPU_TASKS_FROZEN masked transitions > > + * are not considered. > > + */ > > This may not be true for arm guests. ARM guests behave like x86 PV guests in this regard. I expect the comment to be appropriate for both archs or none.