From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754552AbaCJRPM (ORCPT ); Mon, 10 Mar 2014 13:15:12 -0400 Received: from smtp.citrix.com ([66.165.176.89]:17651 "EHLO SMTP.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753882AbaCJRPI (ORCPT ); Mon, 10 Mar 2014 13:15:08 -0400 X-IronPort-AV: E=Sophos;i="4.97,625,1389744000"; d="scan'208";a="109879538" Message-ID: <531DF319.6010800@citrix.com> Date: Mon, 10 Mar 2014 17:15:05 +0000 From: David Vrabel User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.16) Gecko/20121215 Iceowl/1.0b1 Icedove/3.0.11 MIME-Version: 1.0 To: "H. Peter Anvin" CC: , Thomas Gleixner , "Ingo Molnar" , , Sarah Newman Subject: Re: [PATCHv1] x86: don't schedule when handling #NM exception References: <1394468273-13676-1-git-send-email-david.vrabel@citrix.com> <531DEB11.2070709@zytor.com> In-Reply-To: <531DEB11.2070709@zytor.com> Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.80.2.76] X-DLP: MIA1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/03/14 16:40, H. Peter Anvin wrote: > On 03/10/2014 09:17 AM, David Vrabel wrote: >> math_state_restore() is called from the #NM exception handler. It may >> do a GFP_KERNEL allocation (in init_fpu()) which may schedule. >> >> Change this allocation to GFP_ATOMIC, but leave all the other callers >> of init_fpu() or fpu_alloc() using GFP_KERNEL. > > And what the [Finnish] do you do if GFP_ATOMIC fails? The same thing it used to do -- kill the task with SIGKILL. I haven't changed this behaviour. > Sarah's patchset switches Xen PV to use eagerfpu unconditionally, which > removes the dependency on #NM and is the right thing to do. Ok. I'll wait for this series and not pursue this patch any further. David