From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756800Ab1ISXbg (ORCPT ); Mon, 19 Sep 2011 19:31:36 -0400 Received: from hrndva-omtalb.mail.rr.com ([71.74.56.125]:64719 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750811Ab1ISXbf (ORCPT ); Mon, 19 Sep 2011 19:31:35 -0400 X-Authority-Analysis: v=1.1 cv=lfM0d0QHaVz67dfwwr9cyIw6NbaGR/pZhMD6XWNi0kk= c=1 sm=0 a=9yXILFS5HQAA:10 a=5SG0PmZfjMsA:10 a=Q9fys5e9bTEA:10 a=17wjrS5wAhQaEczCPkpxpQ==:17 a=nL07j8xGLd1ldcTufP8A:9 a=PUjeQqilurYA:10 a=17wjrS5wAhQaEczCPkpxpQ==:117 X-Cloudmark-Score: 0 X-Originating-IP: 74.67.83.30 Subject: Re: [RFC][PATCH 1/5] x86: Remove const_udelay() caring about which cpu var it uses From: Steven Rostedt To: Christoph Lameter Cc: linux-kernel@vger.kernel.org, Ingo Molnar , Andrew Morton , Thomas Gleixner , Peter Zijlstra , Christoph Lameter In-Reply-To: References: <20110919212040.745370781@goodmis.org> <20110919212640.343186687@goodmis.org> Content-Type: text/plain; charset="ISO-8859-15" Date: Mon, 19 Sep 2011 19:31:32 -0400 Message-ID: <1316475092.29966.0.camel@gandalf.stny.rr.com> Mime-Version: 1.0 X-Mailer: Evolution 2.32.3 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2011-09-19 at 16:51 -0500, Christoph Lameter wrote: > On Mon, 19 Sep 2011, Steven Rostedt wrote: > > > The __const_udelay() code originally used raw_smp_processor_id() > > in its calculations for a delaying. Probably because if it were > > to migrate, it would take much longer to do so than the requested > > delay. > > > > Switch from this_cpu_read() to __this_cpu_read() to document that > > the read is racy and we do not care. > > Is preemption disabled by all callers to __const_udelay? Nope, because I triggered a splat with it :-) From lots of places. -- Steve