Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751953AbdIAMek (ORCPT ); Fri, 1 Sep 2017 08:34:40 -0400 Received: from merlin.infradead.org ([205.233.59.134]:54268 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751777AbdIAMei (ORCPT ); Fri, 1 Sep 2017 08:34:38 -0400 Date: Fri, 1 Sep 2017 14:34:15 +0200 From: Peter Zijlstra To: "Reshetova, Elena" Cc: Thomas Gleixner , "linux-kernel@vger.kernel.org" , "linux-fsdevel@vger.kernel.org" , "gregkh@linuxfoundation.org" , "viro@zeniv.linux.org.uk" , "tj@kernel.org" , "mingo@redhat.com" , "hannes@cmpxchg.org" , "lizefan@huawei.com" , "acme@kernel.org" , "alexander.shishkin@linux.intel.com" , "eparis@redhat.com" , "akpm@linux-foundation.org" , "arnd@arndb.de" , "luto@kernel.org" , "keescook@chromium.org" , "dvhart@infradead.org" , "ebiederm@xmission.com" Subject: Re: [PATCH 14/15] futex: convert futex_pi_state.refcount to refcount_t Message-ID: <20170901123415.s3fxlyeyourz47av@hirez.programming.kicks-ass.net> References: <1504095773-22895-1-git-send-email-elena.reshetova@intel.com> <1504095773-22895-15-git-send-email-elena.reshetova@intel.com> <20170901093852.it4d4bxoy2lmojrk@hirez.programming.kicks-ass.net> <2236FBA76BA1254E88B949DDB74E612B6FF6347F@IRSMSX102.ger.corp.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <2236FBA76BA1254E88B949DDB74E612B6FF6347F@IRSMSX102.ger.corp.intel.com> User-Agent: NeoMutt/20170609 (1.8.3) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 429 Lines: 8 On Fri, Sep 01, 2017 at 11:05:33AM +0000, Reshetova, Elena wrote: > Actually on the second thought: does the above memory ordering differences > really apply when we have ARCH_HAS_REFCOUNT? To me it looks like the way > how it is currently implemented for x86 is the same way as it is for atomic cases. Never look to x86 for memory ordering, its boring. And yes, for the ARM implementation it can certainly make a difference.