From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752033AbeFEOO0 (ORCPT ); Tue, 5 Jun 2018 10:14:26 -0400 Received: from merlin.infradead.org ([205.233.59.134]:37074 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751197AbeFEOOZ (ORCPT ); Tue, 5 Jun 2018 10:14:25 -0400 Date: Tue, 5 Jun 2018 16:14:16 +0200 From: Peter Zijlstra To: Mark Rutland Cc: linux-kernel@vger.kernel.org, boqun.feng@gmail.com, will.deacon@arm.com, arnd@arndb.de, aryabinin@virtuozzo.com, dvyukov@google.com, glider@google.com, gregkh@linuxfoundation.org, jslaby@suse.com, parri.andrea@gmail.com Subject: Re: [PATCH 0/7] atomics: generate atomic headers Message-ID: <20180605141416.GW12198@hirez.programming.kicks-ass.net> References: <20180529180746.29684-1-mark.rutland@arm.com> <20180605132949.GL12258@hirez.programming.kicks-ass.net> <20180605135823.iqantmeuht6aqotg@lakrids.cambridge.arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180605135823.iqantmeuht6aqotg@lakrids.cambridge.arm.com> User-Agent: Mutt/1.9.5 (2018-04-13) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jun 05, 2018 at 02:58:23PM +0100, Mark Rutland wrote: > Sure, it all works, it's just less than optimal as above, and also means > that we have to duplicate the ifdeffery for optional atomics -- once in > the instrumented atomics, then in the "real" atomics. > > Whereas if we filled in the raw atomics atop of the arch atomics, > everything above that can assume the whole API is present, no ifdeffery > required. Aah, I see your point now. I don't think performance is a particular concern when you enable K*SAN, but getting rid of a fair bunch of ifdeffery is always nice.