From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1034700AbeEXWGW (ORCPT ); Thu, 24 May 2018 18:06:22 -0400 Received: from mail-wm0-f65.google.com ([74.125.82.65]:33927 "EHLO mail-wm0-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1034671AbeEXWGS (ORCPT ); Thu, 24 May 2018 18:06:18 -0400 X-Google-Smtp-Source: AB8JxZrYMSeLw2nsgDnIE+fL8kSiUIVSgNI5FbqKNFpn9Df7IWpbJScCWogs09ImncGD+ocncREbtA== Date: Fri, 25 May 2018 00:06:10 +0200 From: Andrea Parri To: Mark Rutland Cc: Will Deacon , Peter Zijlstra , linux-kernel@vger.kernel.org, mingo@kernel.org, linux-arm-kernel@lists.infradead.org, yamada.masahiro@socionext.com Subject: Re: [PATCH 6/9] asm-generic/bitops/atomic.h: Rewrite using atomic_fetch_* Message-ID: <20180524220610.GA7607@andrea> References: <1527159586-8578-1-git-send-email-will.deacon@arm.com> <1527159586-8578-7-git-send-email-will.deacon@arm.com> <20180524124410.GF12198@hirez.programming.kicks-ass.net> <20180524124734.GE8689@arm.com> <20180524130948.f37eltocl5tnittp@lakrids.cambridge.arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180524130948.f37eltocl5tnittp@lakrids.cambridge.arm.com> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Mark, > As an aside, If I complete the autogeneration stuff, it'll be possible > to generate those. I split out the necessary barriers in [1], but I > still have a lot of other preparatory cleanup to do. I do grasp the rationale behind that naming: __atomic_mb_{before,after}_{acquire,release,fence}() and yet I remain puzzled by it: For example, can you imagine (using): __atomic_mb_before_acquire() ? (as your __atomic_mb_after_acquire() is whispering me "acquire-fences"...) Another example: the "atomic" in that "smp_mb__{before,after}_atomic" is so "suggestive"! (think at x86...), but it's not explicit in the proposed names. I don't have other names to suggest at the moment... ;/ (aka just saying) Andrea > > IIUC, the void-returning atomic ops are relaxed, so trying to unify that > with the usual rule that no suffix means fence will slow things down > unless we want to do a treewide substitition to fixup for that. > > Thanks, > Mark. > > [1] https://git.kernel.org/pub/scm/linux/kernel/git/mark/linux.git/commit/?h=atomics/api-unification&id=c6b9ff2627d06776e427a7f1a7f83caeff3db536