From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933557AbcKQRCY (ORCPT ); Thu, 17 Nov 2016 12:02:24 -0500 Received: from foss.arm.com ([217.140.101.70]:56188 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932235AbcKQRCU (ORCPT ); Thu, 17 Nov 2016 12:02:20 -0500 Date: Thu, 17 Nov 2016 16:36:24 +0000 From: Will Deacon To: Peter Zijlstra Cc: Boqun Feng , gregkh@linuxfoundation.org, keescook@chromium.org, elena.reshetova@intel.com, arnd@arndb.de, tglx@linutronix.de, mingo@kernel.org, hpa@zytor.com, dave@progbits.org, linux-kernel@vger.kernel.org Subject: Re: [RFC][PATCH 7/7] kref: Implement using refcount_t Message-ID: <20161117163624.GP22855@arm.com> References: <20161114173946.501528675@infradead.org> <20161114174446.832175072@infradead.org> <20161115123337.GD12110@tardis.cn.ibm.com> <20161115130154.GX3117@twins.programming.kicks-ass.net> <20161115141909.GJ27541@tardis.cn.ibm.com> <20161117092800.GD3142@twins.programming.kicks-ass.net> <20161117120836.GE22855@arm.com> <20161117161110.GG3117@twins.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20161117161110.GG3117@twins.programming.kicks-ass.net> 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 Thu, Nov 17, 2016 at 05:11:10PM +0100, Peter Zijlstra wrote: > On Thu, Nov 17, 2016 at 12:08:36PM +0000, Will Deacon wrote: > > All sounds reasonable to me. It's worth pointing out that you can't create > > order using a control dependency hanging off the status flag of a > > store-conditional, but the code in question here has the dependency from > > the loaded value, which is sufficient. > > Yeah, I'm always surprised by that 'feature'. Is that ARM specific? Or > so more LL/SC archs have this? In general, I'm not sure, but I think PPC does allow for the control dependency. Will