From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753111Ab0CBONt (ORCPT ); Tue, 2 Mar 2010 09:13:49 -0500 Received: from mx2.mail.elte.hu ([157.181.151.9]:41968 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751390Ab0CBONs (ORCPT ); Tue, 2 Mar 2010 09:13:48 -0500 Date: Tue, 2 Mar 2010 15:12:57 +0100 From: Ingo Molnar To: "Paul E. McKenney" Cc: linux-kernel@vger.kernel.org, laijs@cn.fujitsu.com, dipankar@in.ibm.com, akpm@linux-foundation.org, mathieu.desnoyers@polymtl.ca, josh@joshtriplett.org, dvhltc@us.ibm.com, niv@us.ibm.com, tglx@linutronix.de, peterz@infradead.org, rostedt@goodmis.org, Valdis.Kletnieks@vt.edu, dhowells@redhat.com Subject: Re: [PATCH RFC tip/core/rcu 1/2] rcu: suppress RCU lockdep warnings during early boot Message-ID: <20100302141257.GA28917@elte.hu> References: <20100301190329.GA26892@linux.vnet.ibm.com> <1267470234-27150-1-git-send-email-paulmck@linux.vnet.ibm.com> <20100302122059.GA8247@elte.hu> <20100302132718.GB6821@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20100302132718.GB6821@linux.vnet.ibm.com> User-Agent: Mutt/1.5.20 (2009-08-17) X-ELTE-SpamScore: 0.0 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=0.0 required=5.9 tests=none autolearn=no SpamAssassin version=3.2.5 _SUMMARY_ Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Paul E. McKenney wrote: > On Tue, Mar 02, 2010 at 01:20:59PM +0100, Ingo Molnar wrote: > > > > * Paul E. McKenney wrote: > > > > > + if (!rcu_scheduler_active || !debug_locks) > > > + return 1; > > > + return lock_is_held(&rcu_lock_map); > > > > > + if (!rcu_scheduler_active || !debug_locks) > > > + return 1; > > > + return lock_is_held(&rcu_bh_lock_map); > > > > i guess there could be a common helper here? > > Will do! > > > Also, could we clear rcu_scheduler_active when we clear debug_locks? That way > > only a single test is needed, a generic 'is lock debugging active'. > > Doing that will break synchronize_rcu(), which returns immediately if > !rcu_scheduler_active. Ok - then have an debug_rcu flag which is cleared appropriately - so that the fastpath impact is reduced? Ingo