From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759464Ab1JGCCW (ORCPT ); Thu, 6 Oct 2011 22:02:22 -0400 Received: from mga14.intel.com ([143.182.124.37]:27328 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752908Ab1JGCCV (ORCPT ); Thu, 6 Oct 2011 22:02:21 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.68,499,1312182000"; d="scan'208";a="24050872" From: Andi Kleen To: "hpanvin\@gmail.com" Cc: Josh Stone , linux-kernel@vger.kernel.org, Thomas Gleixner , Ingo Molnar , x86@kernel.org, Masami Hiramatsu , Srikar Dronamraju , Jakub Jelinek Subject: Re: [PATCH] x86: Make variable_test_bit reference all of *addr References: <1317945508-19575-1-git-send-email-jistone@redhat.com> <990b8719-066b-4e1d-892f-6a3ea4241fb2@email.android.com> Date: Thu, 06 Oct 2011 19:02:20 -0700 In-Reply-To: <990b8719-066b-4e1d-892f-6a3ea4241fb2@email.android.com> (hpa@zytor.com's message of "Thu, 06 Oct 2011 18:37:27 -0700") Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/23.2 (gnu/linux) 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 "hpanvin@gmail.com" writes: > This is concerning... the kernel relies heavily on asm volatile being a universal memory consumer. If that is suddenly broken, we are f*** in many, many, MANY places in the kernel all of a sudden! I don't think that's true. We generally add "memory" clobbers for this purpose. asm volatile just means "don't move" Just this one doesn't have it for unknown reasons (someone overoptimizing?) -Andi -- ak@linux.intel.com -- Speaking for myself only