From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752149AbeBTNCL (ORCPT ); Tue, 20 Feb 2018 08:02:11 -0500 Received: from bombadil.infradead.org ([198.137.202.133]:46618 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752119AbeBTNCJ (ORCPT ); Tue, 20 Feb 2018 08:02:09 -0500 Date: Mon, 19 Feb 2018 15:05:53 +0100 From: Peter Zijlstra To: Will Deacon Cc: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, mingo@kernel.org Subject: Re: [RFC PATCH 3/5] asm-generic/bitops/atomic.h: Rewrite using atomic_fetch_* Message-ID: <20180219140553.GT25201@hirez.programming.kicks-ass.net> References: <1518708575-12284-1-git-send-email-will.deacon@arm.com> <1518708575-12284-4-git-send-email-will.deacon@arm.com> <20180215170847.GD25181@hirez.programming.kicks-ass.net> <20180215182049.GC15274@arm.com> <20180216103520.GC25201@hirez.programming.kicks-ass.net> <20180219140151.GE30394@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180219140151.GE30394@arm.com> User-Agent: Mutt/1.9.2 (2017-12-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Feb 19, 2018 at 02:01:51PM +0000, Will Deacon wrote: > If it's defined, then we could consider using cmpxchg64 to build atomic64 > instead of the locks. But even then, I'm not sure we're really helping > anybody out in practice. yeah, most 64bit archs have more atomics or ll/sc and would not use it anyway I suppose.