Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933697AbZJMOx1 (ORCPT ); Tue, 13 Oct 2009 10:53:27 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1759966AbZJMOx0 (ORCPT ); Tue, 13 Oct 2009 10:53:26 -0400 Received: from smtp2.ultrahosting.com ([74.213.174.253]:59544 "EHLO smtp.ultrahosting.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1759957AbZJMOxZ (ORCPT ); Tue, 13 Oct 2009 10:53:25 -0400 Date: Tue, 13 Oct 2009 10:45:39 -0400 (EDT) From: Christoph Lameter X-X-Sender: cl@gentwo.org To: Tejun Heo cc: Stephen Rothwell , Rusty Russell , Ingo Molnar , linux-next@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] this_cpu: Use this_cpu_xx in trace_functions_graph.c In-Reply-To: <4AD49317.6080503@kernel.org> Message-ID: References: <20091013144812.bdb376aa.sfr@canb.auug.org.au> <4AD48EC4.8040701@kernel.org> <4AD49317.6080503@kernel.org> User-Agent: Alpine 1.10 (DEB 962 2008-03-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 863 Lines: 19 On Tue, 13 Oct 2009, Tejun Heo wrote: > Oh... one question tho. I used __this_cpu_*() as other conversions > but I think we should be using the version without the underscores. > The relationship between get_cpu_var() and __get_cpu_var() is > different from the one between this_cpu_*() and __this_cpu_*(). For operations like inc/add/dec/sub you need to use the version with __ otherwise the arches that do not support these operations will have to generate useless expensive code that disables / reenables preempt. For this_cpu_ptr / __this_cpu_ptr it does not matter. this_cpu_ptr gives you additional checks. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/