From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753852Ab0DAHXx (ORCPT ); Thu, 1 Apr 2010 03:23:53 -0400 Received: from cn.fujitsu.com ([222.73.24.84]:52843 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1753778Ab0DAHXq (ORCPT ); Thu, 1 Apr 2010 03:23:46 -0400 Message-ID: <4BB44A15.60306@cn.fujitsu.com> Date: Thu, 01 Apr 2010 15:24:05 +0800 From: Lai Jiangshan User-Agent: Thunderbird 2.0.0.6 (Windows/20070728) MIME-Version: 1.0 To: paulmck@linux.vnet.ibm.com CC: Ingo Molnar , LKML Subject: Re: [PATCH] rcu: don't call rcu_preempt_note_context_switch() in rcu_check_callbacks() References: <4BB014DF.9030905@cn.fujitsu.com> <20100329044236.GB2343@linux.vnet.ibm.com> <4BB1C7C5.5070700@cn.fujitsu.com> <20100330160339.GB2513@linux.vnet.ibm.com> <20100331153656.GA4623@linux.vnet.ibm.com> <4BB3EF25.1040804@cn.fujitsu.com> <20100401011747.GJ2461@linux.vnet.ibm.com> In-Reply-To: <20100401011747.GJ2461@linux.vnet.ibm.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Paul E. McKenney wrote: > Possibly by moving the clearing of RCU_READ_UNLOCK_NEED_QS to > rcu_preempt_check_callbacks() current rcu_preempt_check_callbacks() already has code to clear RCU_READ_UNLOCK_NEED_QS. > -- or to rcu_preempt_qs(). The latter is in > some sense cleaner, but higher overhead and probably unnecessary. Hmmm... > Alternatively, require that all callers to rcu_preempt_qs() disable > irqs. This affects only one callsite, which has a local_irq_disable() > immediately following anyway. ;-) > > Thanx, Paul