From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753257AbdCPQJx (ORCPT ); Thu, 16 Mar 2017 12:09:53 -0400 Received: from mail-yw0-f177.google.com ([209.85.161.177]:34898 "EHLO mail-yw0-f177.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752149AbdCPQJw (ORCPT ); Thu, 16 Mar 2017 12:09:52 -0400 Date: Thu, 16 Mar 2017 12:09:44 -0400 From: Tejun Heo To: Peter Zijlstra Cc: Oleg Nesterov , Linus Torvalds , Andrew Morton , Thomas Gleixner , Chris Mason , linux-kernel@vger.kernel.org, kernel-team@fb.com Subject: Re: [PATCH 1/2] kthread: add barriers to set_kthread_struct() and to_kthread() Message-ID: <20170316160944.GE15810@htj.duckdns.org> References: <20170315231827.GA13656@htj.duckdns.org> <20170316145436.GA24478@redhat.com> <20170316153301.GA15810@htj.duckdns.org> <20170316153843.GB15810@htj.duckdns.org> <20170316155534.zbtmy5v7gh6pbuhl@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170316155534.zbtmy5v7gh6pbuhl@hirez.programming.kicks-ass.net> User-Agent: Mutt/1.7.1 (2016-10-04) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Mar 16, 2017 at 04:55:34PM +0100, Peter Zijlstra wrote: > > Oops, as for adding lockless_assign_pointer(), wouldn't smp_wmb() be a > > better match for smp_read_barrier_depends()? ISTR acquire/release > > pairs being more expensive on some archs. > > 88c1863066cc ("rcu: Define rcu_assign_pointer() in terms of smp_store_release()") Hmmm, nice, can we always prefer store_release over wmb from now on? Thanks. -- tejun