From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753680Ab2C0M0q (ORCPT ); Tue, 27 Mar 2012 08:26:46 -0400 Received: from hrndva-omtalb.mail.rr.com ([71.74.56.122]:15734 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753369Ab2C0M0L (ORCPT ); Tue, 27 Mar 2012 08:26:11 -0400 X-Authority-Analysis: v=2.0 cv=P4S4d18u c=1 sm=0 a=ZycB6UtQUfgMyuk2+PxD7w==:17 a=XQbtiDEiEegA:10 a=NFM--E4xPHYA:10 a=5SG0PmZfjMsA:10 a=Q9fys5e9bTEA:10 a=iivZJ_HrVVKMCwYqsd4A:9 a=PUjeQqilurYA:10 a=ZycB6UtQUfgMyuk2+PxD7w==:117 X-Cloudmark-Score: 0 X-Originating-IP: 74.67.80.29 Message-ID: <1332851167.23924.125.camel@gandalf.stny.rr.com> Subject: Re: [PATCH RFC] rcu: Make __rcu_read_lock() inlinable From: Steven Rostedt To: paulmck@linux.vnet.ibm.com Cc: Peter Zijlstra , linux-kernel@vger.kernel.org, mingo@elte.hu, laijs@cn.fujitsu.com, dipankar@in.ibm.com, akpm@linux-foundation.org, mathieu.desnoyers@efficios.com, josh@joshtriplett.org, niv@us.ibm.com, tglx@linutronix.de, Valdis.Kletnieks@vt.edu, dhowells@redhat.com, eric.dumazet@gmail.com, darren@dvhart.com, fweisbec@gmail.com, patches@linaro.org, torvalds@linux-foundation.org Date: Tue, 27 Mar 2012 08:26:07 -0400 In-Reply-To: <20120327051515.GO2450@linux.vnet.ibm.com> References: <20120325205249.GA29528@linux.vnet.ibm.com> <1332748484.16159.61.camel@twins> <20120326183232.GK2450@linux.vnet.ibm.com> <1332787630.16159.182.camel@twins> <20120327051515.GO2450@linux.vnet.ibm.com> Content-Type: text/plain; charset="ISO-8859-15" X-Mailer: Evolution 3.2.2-1 Content-Transfer-Encoding: 7bit Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2012-03-26 at 22:15 -0700, Paul E. McKenney wrote: > Hmmm... I am not yet sure whether it is easier to make RCU use legal > in switch_to() or to detect it. I am inclined to take whatever course > is easiest, which is likely to make it legal. :-/ We could just declare that we do not allow tracepoints in arch specific "switch_to" code. Then you shouldn't need to worry about RCU in switch_to(). sched_rcu can still work there correct? That is, a synchronize_sched() should not be affected. As that is needed for the function tracing, and that may be called within a switch_to. -- Steve