From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755571Ab0CDQcP (ORCPT ); Thu, 4 Mar 2010 11:32:15 -0500 Received: from hera.kernel.org ([140.211.167.34]:48451 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755375Ab0CDQcL (ORCPT ); Thu, 4 Mar 2010 11:32:11 -0500 Date: Thu, 4 Mar 2010 16:31:29 GMT From: tip-bot for Masami Hiramatsu Cc: linux-kernel@vger.kernel.org, hpa@zytor.com, mingo@redhat.com, mathieu.desnoyers@efficios.com, dle-develop@lists.sourceforge.net, tglx@linutronix.de, jbaron@redhat.com, mhiramat@redhat.com, mingo@elte.hu, systemtap@sources.redhat.com Reply-To: mingo@redhat.com, hpa@zytor.com, linux-kernel@vger.kernel.org, mathieu.desnoyers@efficios.com, dle-develop@lists.sourceforge.net, tglx@linutronix.de, jbaron@redhat.com, mhiramat@redhat.com, mingo@elte.hu, systemtap@sources.redhat.com In-Reply-To: <20100304033850.3819.74590.stgit@localhost6.localdomain6> References: <20100304033850.3819.74590.stgit@localhost6.localdomain6> To: linux-tip-commits@vger.kernel.org Subject: [tip:perf/pebs] x86: Issue at least one memory barrier in stop_machine_text_poke() Message-ID: Git-Commit-ID: e5a11016643d1ab7172193591506d33a844734cc X-Mailer: tip-git-log-daemon MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.2.3 (hera.kernel.org [127.0.0.1]); Thu, 04 Mar 2010 16:31:30 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: e5a11016643d1ab7172193591506d33a844734cc Gitweb: http://git.kernel.org/tip/e5a11016643d1ab7172193591506d33a844734cc Author: Masami Hiramatsu AuthorDate: Wed, 3 Mar 2010 22:38:50 -0500 Committer: Ingo Molnar CommitDate: Thu, 4 Mar 2010 11:39:21 +0100 x86: Issue at least one memory barrier in stop_machine_text_poke() Fix stop_machine_text_poke() to issue smp_mb() before exiting waiting loop, and use cpu_relax() for waiting. Changes in v2: - Don't use ACCESS_ONCE(). Signed-off-by: Masami Hiramatsu Acked-by: Mathieu Desnoyers Cc: systemtap Cc: DLE Cc: Jason Baron LKML-Reference: <20100304033850.3819.74590.stgit@localhost6.localdomain6> Signed-off-by: Ingo Molnar --- arch/x86/kernel/alternative.c | 4 ++-- 1 files changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c index c41f13c..e0b8770 100644 --- a/arch/x86/kernel/alternative.c +++ b/arch/x86/kernel/alternative.c @@ -595,8 +595,8 @@ static int __kprobes stop_machine_text_poke(void *data) wrote_text = 1; } else { while (!wrote_text) - smp_rmb(); - sync_core(); + cpu_relax(); + smp_mb(); /* Load wrote_text before following execution */ } flush_icache_range((unsigned long)tpp->addr,