From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754003AbbLJU34 (ORCPT ); Thu, 10 Dec 2015 15:29:56 -0500 Received: from bombadil.infradead.org ([198.137.202.9]:47054 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751381AbbLJU3z (ORCPT ); Thu, 10 Dec 2015 15:29:55 -0500 Date: Thu, 10 Dec 2015 21:29:39 +0100 From: Peter Zijlstra To: "Paul E. McKenney" Cc: linux-kernel@vger.kernel.org, mingo@kernel.org, jiangshanlai@gmail.com, dipankar@in.ibm.com, akpm@linux-foundation.org, mathieu.desnoyers@efficios.com, josh@joshtriplett.org, tglx@linutronix.de, rostedt@goodmis.org, dhowells@redhat.com, edumazet@google.com, dvhart@linux.intel.com, fweisbec@gmail.com, oleg@redhat.com, bobby.prani@gmail.com Subject: Re: [PATCH v2 tip/core/rcu 03/11] rcu: Move smp_mb() from rcu_seq_snap() to rcu_exp_gp_seq_snap() Message-ID: <20151210202939.GC6356@twins.programming.kicks-ass.net> References: <20151209230243.GA32518@linux.vnet.ibm.com> <1449702188-493-3-git-send-email-paulmck@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1449702188-493-3-git-send-email-paulmck@linux.vnet.ibm.com> User-Agent: Mutt/1.5.21 (2012-12-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Dec 09, 2015 at 03:03:00PM -0800, Paul E. McKenney wrote: > The memory barrier in rcu_seq_snap() is needed only for grace periods, > so this commit moves it to the grace-period-oriented wrapper > rcu_exp_gp_seq_snap(). This is a bit short for a memory barrier changelog. I think I remember enough of the code to see this is indeed so, but who knows who will remember what in another few weeks :-)