From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755658AbbBPR7Y (ORCPT ); Mon, 16 Feb 2015 12:59:24 -0500 Received: from mx1.redhat.com ([209.132.183.28]:38833 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755394AbbBPR7Q (ORCPT ); Mon, 16 Feb 2015 12:59:16 -0500 Message-ID: <54E22FCD.3030202@redhat.com> Date: Mon, 16 Feb 2015 12:58:37 -0500 From: Rik van Riel User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.3.0 MIME-Version: 1.0 To: Borislav Petkov , oleg@redhat.com CC: dave.hansen@linux.intel.com, sbsiddha@gmail.com, luto@amacapital.net, tglx@linutronix.de, mingo@kernel.org, hpa@zytor.com, fenghua.yu@intel.com, x86@kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/8] x86, fpu: unlazy_fpu: don't reset thread.fpu_counter References: <1423252925-14451-1-git-send-email-riel@redhat.com> <1423252925-14451-2-git-send-email-riel@redhat.com> <20150216170433.GF4458@pd.tnic> In-Reply-To: <20150216170433.GF4458@pd.tnic> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 02/16/2015 12:04 PM, Borislav Petkov wrote: > ... and so by looking at the unlazy_fpu() call sites, I think this > makes sense. > > So how's that for a commit message instead: > > --- x86, fpu, unlazy_fpu: Don't reset thread.fpu_counter > > The "else" branch clears ->fpu_counter as a remnant of the lazy > FPU usage counting: > > e07e23e1fd30 ("[PATCH] non lazy "sleazy" fpu implementation") > > However, switch_fpu_prepare() does this now so that else branch is > superfluous. > > If we do use_eager_fpu(), then this has no effect. Otherwise, if > we actually wanted to prevent fpu preload after the context switch > we would need to reset it unconditionally, even if > __thread_has_fpu(). --- > > ? Good detective work. Your changelog makes sense to me. - -- All rights reversed -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQEcBAEBAgAGBQJU4i/NAAoJEM553pKExN6DWn4H/ArcSaAwA5ClOmxNACOTS644 m+8d/+3XZd+nWKBxLY2iyigLQ3FSek2dPSilDMSxtN97oFsG9mFw14gvP1/oR9OU 6vVhfuBWPRQ+Ay7CAL40v1acvzbYSTQJ6i9IJq20EFhuAS1CFwksOr9gQrhRHed1 FxFUpSnss0+p6Jp+RXY+UG2gNtSUOwgLzZFb1cmgeD5APC+RShGqHgDPTlNUESGK f9g3QzOD3KAz8fVNzTwumN1nJzPNx6yBXuazu3U8HAxzcMskVvWSOEyEBlo48CdR XxjLpI95qgzwUUQGFj6yax8ciq6nQGk6TsgqbdqHlpHSQ2zWU1F8XefGAS/r0vE= =CXAX -----END PGP SIGNATURE-----