From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934084AbbEMKcE (ORCPT ); Wed, 13 May 2015 06:32:04 -0400 Received: from mail.skyhub.de ([78.46.96.112]:46991 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933526AbbEMKcC (ORCPT ); Wed, 13 May 2015 06:32:02 -0400 Date: Wed, 13 May 2015 12:31:57 +0200 From: Borislav Petkov To: "Paul E. McKenney" Cc: linux-kernel@vger.kernel.org, mingo@kernel.org, laijs@cn.fujitsu.com, dipankar@in.ibm.com, akpm@linux-foundation.org, mathieu.desnoyers@efficios.com, josh@joshtriplett.org, tglx@linutronix.de, peterz@infradead.org, rostedt@goodmis.org, dhowells@redhat.com, edumazet@google.com, dvhart@linux.intel.com, fweisbec@gmail.com, oleg@redhat.com, bobby.prani@gmail.com, linux-edac@vger.kernel.org, Tony Luck Subject: Re: [PATCH tip/core/rcu 1/4] mce: Stop using array-index-based RCU primitives Message-ID: <20150513103157.GF1517@pd.tnic> References: <20150512211814.GA31939@linux.vnet.ibm.com> <1431465524-32246-1-git-send-email-paulmck@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <1431465524-32246-1-git-send-email-paulmck@linux.vnet.ibm.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, May 12, 2015 at 02:18:41PM -0700, Paul E. McKenney wrote: > From: "Paul E. McKenney" > > Because mce is arch-specific x86 code, there is little or no > performance benefit of using rcu_dereference_index_check() over using > smp_load_acquire(). It also turns out that mce is the only place that > array-index-based RCU is used, and it would be convenient to drop > this portion of the RCU API. > > This patch therefore changes rcu_dereference_index_check() uses to > smp_load_acquire(), but keeping the lockdep diagnostics, and also > changes rcu_access_index() uses to READ_ONCE(). > > Signed-off-by: Paul E. McKenney > Cc: linux-edac@vger.kernel.org > Cc: Tony Luck > Cc: Borislav Petkov Looks good to me. If it is easier for you carrying it in your tree: Acked-by: Borislav Petkov Otherwise, let me know. Thanks. -- Regards/Gruss, Boris. ECO tip #101: Trim your mails when you reply. --