From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754125Ab1ITDRu (ORCPT ); Mon, 19 Sep 2011 23:17:50 -0400 Received: from hrndva-omtalb.mail.rr.com ([71.74.56.125]:42507 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753759Ab1ITDRt (ORCPT ); Mon, 19 Sep 2011 23:17:49 -0400 X-Authority-Analysis: v=1.1 cv=lfM0d0QHaVz67dfwwr9cyIw6NbaGR/pZhMD6XWNi0kk= c=1 sm=0 a=3kNrfhY1ZosA:10 a=5SG0PmZfjMsA:10 a=Q9fys5e9bTEA:10 a=17wjrS5wAhQaEczCPkpxpQ==:17 a=Kp9ooNmR4kA3jbtXADwA:9 a=PUjeQqilurYA:10 a=17wjrS5wAhQaEczCPkpxpQ==:117 X-Cloudmark-Score: 0 X-Originating-IP: 74.67.83.30 Subject: Re: [RFC][PATCH 0/5] Introduce checks for preemptable code for this_cpu_read/write() From: Steven Rostedt To: Andi Kleen Cc: linux-kernel@vger.kernel.org, Ingo Molnar , Andrew Morton , Thomas Gleixner , Peter Zijlstra , Christoph Lameter In-Reply-To: <1316488378.29966.35.camel@gandalf.stny.rr.com> References: <20110919212040.745370781@goodmis.org> <1316488378.29966.35.camel@gandalf.stny.rr.com> Content-Type: text/plain; charset="ISO-8859-15" Date: Mon, 19 Sep 2011 23:17:46 -0400 Message-ID: <1316488666.29966.38.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 23:12 -0400, Steven Rostedt wrote: > Actually, that's part of the issue. RT has made spin_locks not migrate. > But this has also increased the overhead of those same spinlocks. I'm > hoping to do away with the big hammer approach (although Thomas is less > interested in this). I would like to have areas that require per-cpu > variables to be annotated, and not have every spinlock disable > preemption. > The point is, if I do make this change. It is even more essential that I detect the preempt enable use of this_cpu() and friends. As the spin_locks() will no longer be giving that guarantee. -- Steve