From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755072Ab1LEJmh (ORCPT ); Mon, 5 Dec 2011 04:42:37 -0500 Received: from casper.infradead.org ([85.118.1.10]:56338 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754420Ab1LEJmg convert rfc822-to-8bit (ORCPT ); Mon, 5 Dec 2011 04:42:36 -0500 Message-ID: <1323078096.32012.14.camel@twins> Subject: Re: [PATCH RFC tip/core/rcu 7/7] rcu: Quiet RCU-lockdep warnings involving interrupt disabling From: Peter Zijlstra To: "Paul E. McKenney" Cc: linux-kernel@vger.kernel.org, mingo@elte.hu, laijs@cn.fujitsu.com, dipankar@in.ibm.com, akpm@linux-foundation.org, mathieu.desnoyers@polymtl.ca, josh@joshtriplett.org, niv@us.ibm.com, tglx@linutronix.de, rostedt@goodmis.org, Valdis.Kletnieks@vt.edu, dhowells@redhat.com, eric.dumazet@gmail.com, darren@dvhart.com, patches@linaro.org, Yong Zhang Date: Mon, 05 Dec 2011 10:41:36 +0100 In-Reply-To: <1322937282-19846-7-git-send-email-paulmck@linux.vnet.ibm.com> References: <20111203183417.GA18914@linux.vnet.ibm.com> <1322937282-19846-7-git-send-email-paulmck@linux.vnet.ibm.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8BIT X-Mailer: Evolution 3.2.1- Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, 2011-12-03 at 10:34 -0800, Paul E. McKenney wrote: > From: Yong Zhang > > RCU-lockdep will issue warnings given the following use pattern: > > rcu_read_lock(); > local_irq_disable(); > rcu_read_unlock(); > local_irq_enable(); > > However, this use pattern is legal except for the scheduler's runqueue > and priority-inheritance locks (and any other locks that the scheduler > might use during priority-inheritance operations). So what does this patch do? Make it not complain when you do the above? How often does this pattern actually happen? Can't be that often otherwise we'd have had more complaints, no?