From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752788AbbC3Nh1 (ORCPT ); Mon, 30 Mar 2015 09:37:27 -0400 Received: from smtprelay0178.hostedemail.com ([216.40.44.178]:41802 "EHLO smtprelay.hostedemail.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751622AbbC3NhZ (ORCPT ); Mon, 30 Mar 2015 09:37:25 -0400 X-Session-Marker: 726F737465647440676F6F646D69732E6F7267 X-Spam-Summary: 40,2.5,0,,d41d8cd98f00b204,rostedt@goodmis.org,:::::::::::,RULES_HIT:41:355:379:541:599:800:960:973:988:989:1260:1277:1311:1313:1314:1345:1359:1437:1515:1516:1518:1534:1539:1593:1594:1711:1730:1747:1777:1792:2393:2553:2559:2562:3138:3139:3140:3141:3142:3352:3622:3865:3867:3868:3872:3874:5007:6261:7875:7903:10004:10400:10848:10967:11026:11232:11658:11914:12043:12109:12517:12519:12663:12740:13069:13311:13357:21080:21088,0,RBL:none,CacheIP:none,Bayesian:0.5,0.5,0.5,Netcheck:none,DomainCache:0,MSF:not bulk,SPF:fn,MSBL:0,DNSBL:none,Custom_rules:0:0:0 X-HE-Tag: wound79_5d96140fc5301 X-Filterd-Recvd-Size: 1863 Date: Mon, 30 Mar 2015 09:37:20 -0400 From: Steven Rostedt To: Christoph Lameter Cc: linux-kernel@vger.kernel.org, Ingo Molnar , Andrew Morton , stable@vger.kernel.org, Uwe Kleine-Koenig Subject: Re: [for-next][PATCH 1/4] ring-buffer: Replace this_cpu_*() with __this_cpu_*() Message-ID: <20150330093720.6bfbf82f@gandalf.local.home> In-Reply-To: References: <20150325130011.709478161@goodmis.org> <20150325130037.896265791@goodmis.org> <20150327161133.505d4074@gandalf.local.home> X-Mailer: Claws Mail 3.11.1 (GTK+ 2.24.25; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 30 Mar 2015 07:44:30 -0500 (CDT) Christoph Lameter wrote: > > > > > > or more compact > > > > > > unsigned int val = __this_cpu_read(current_context); > > > > > > __this_cpu_write(current_context, val & (val - 1)); > > > > Maybe I'll just use your compact version. > > Hmmm... It could even be more compact > > __this_cpu_and(current_context, __this_cpu_read(current_context) - 1); Hmm, I didn't realize there was an "and" version. I'm guessing this would bring down the instruction count even more? /me tries it. I just finished testing my previous version. If this does prove to be more compact, I'll have to replace that one with this one. -- Steve