From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754373Ab0C2WgN (ORCPT ); Mon, 29 Mar 2010 18:36:13 -0400 Received: from e8.ny.us.ibm.com ([32.97.182.138]:38336 "EHLO e8.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753411Ab0C2WgL (ORCPT ); Mon, 29 Mar 2010 18:36:11 -0400 Date: Mon, 29 Mar 2010 15:36:09 -0700 From: "Paul E. McKenney" To: David Howells Cc: Eric Dumazet , Trond.Myklebust@netapp.com, linux-nfs@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] NFS: Fix RCU warnings in nfs_inode_return_delegation_noreclaim() [ver #2] Message-ID: <20100329223609.GR2569@linux.vnet.ibm.com> Reply-To: paulmck@linux.vnet.ibm.com References: <20100329210520.GN2569@linux.vnet.ibm.com> <20100329192159.GM2569@linux.vnet.ibm.com> <20100319022527.GC2894@linux.vnet.ibm.com> <20100318133302.29754.1584.stgit@warthog.procyon.org.uk> <19192.1269889348@redhat.com> <23274.1269893706@redhat.com> <25276.1269901350@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <25276.1269901350@redhat.com> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Mar 29, 2010 at 11:22:30PM +0100, David Howells wrote: > Paul E. McKenney wrote: > > > And rcu_dereference_raw() is the same as the old rcu_dereference(). > > Exactly. That's the other half of the issue - that interpolates a redundant > memory barrier. Only on Alpha. Otherwise only a volatile access. Thanx, Paul