Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753418AbYH3OKU (ORCPT ); Sat, 30 Aug 2008 10:10:20 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751018AbYH3OKH (ORCPT ); Sat, 30 Aug 2008 10:10:07 -0400 Received: from e34.co.us.ibm.com ([32.97.110.152]:45453 "EHLO e34.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750808AbYH3OKF (ORCPT ); Sat, 30 Aug 2008 10:10:05 -0400 Date: Sat, 30 Aug 2008 07:10:01 -0700 From: "Paul E. McKenney" To: Peter Zijlstra Cc: linux-kernel@vger.kernel.org, cl@linux-foundation.org, mingo@elte.hu, akpm@linux-foundation.org, manfred@colorfullife.com, dipankar@in.ibm.com, josht@linux.vnet.ibm.com, schamp@sgi.com, niv@us.ibm.com, dvhltc@us.ibm.com, ego@in.ibm.com, laijs@cn.fujitsu.com, rostedt@goodmis.org, Mathieu Desnoyers Subject: Re: [PATCH, RFC, tip/core/rcu] v3 scalable classic RCU implementation Message-ID: <20080830141001.GD7107@linux.vnet.ibm.com> Reply-To: paulmck@linux.vnet.ibm.com References: <20080821234318.GA1754@linux.vnet.ibm.com> <20080825000738.GA24339@linux.vnet.ibm.com> <20080830004935.GA28548@linux.vnet.ibm.com> <1220088780.8426.1.camel@twins> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1220088780.8426.1.camel@twins> User-Agent: Mutt/1.5.15+20070412 (2007-04-11) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1212 Lines: 28 On Sat, Aug 30, 2008 at 11:33:00AM +0200, Peter Zijlstra wrote: > On Fri, 2008-08-29 at 17:49 -0700, Paul E. McKenney wrote: > > > Some shortcomings: > > > > o Entering and leaving dynticks idle mode is a quiescent state, > > but the current patch doesn't take advantage of this (noted > > by Manfred). It appears that it should be possible to make > > nmi_enter() and nmi_exit() provide an in_nmi(), which would make > > it possible for rcu_irq_enter() and rcu_irq_exit() to figure > > out whether it is safe to tell RCU about the quiescent state -- > > and also greatly simplify the code. > > Already done and available in the -tip tree, curtesy of Mathieu. Very cool!!! I see one of his patches at http://lkml.org/lkml/2008/4/17/342, but how do I find out which branch of -tip this is on? (I am learning git, but it is a slow process...) This would also simplify preemptable RCU's dyntick interface, removing the need for proofs. Thanx, Paul -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/