From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933598Ab0DHUdL (ORCPT ); Thu, 8 Apr 2010 16:33:11 -0400 Received: from mx1.redhat.com ([209.132.183.28]:23179 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933486Ab0DHUdB (ORCPT ); Thu, 8 Apr 2010 16:33:01 -0400 Message-ID: <4BBE3D2F.6030609@redhat.com> Date: Thu, 08 Apr 2010 16:31:43 -0400 From: Rik van Riel User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.7) Gecko/20100120 Fedora/3.0.1-1.fc12 Lightning/1.0b2pre Thunderbird/3.0.1 MIME-Version: 1.0 To: Peter Zijlstra CC: Andrea Arcangeli , Avi Kivity , Thomas Gleixner , Ingo Molnar , akpm@linux-foundation.org, Linus Torvalds , linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, Benjamin Herrenschmidt , David Miller , Hugh Dickins , Mel Gorman , Nick Piggin Subject: Re: [PATCH 01/13] powerpc: Add rcu_read_lock() to gup_fast() implementation References: <20100408191737.296180458@chello.nl> <20100408192722.643778654@chello.nl> In-Reply-To: <20100408192722.643778654@chello.nl> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 04/08/2010 03:17 PM, Peter Zijlstra wrote: > The powerpc page table freeing relies on the fact that IRQs hold off > an RCU grace period, this is currently true for all existing RCU > implementations but is not an assumption Paul wants to support. > > Therefore, also take the RCU read lock along with disabling IRQs to > ensure the RCU grace period does at least cover these lookups. > > Requested-by: Paul E. McKenney > Signed-off-by: Peter Zijlstra > Cc: Nick Piggin > Cc: Benjamin Herrenschmidt Reviewed-by: Rik van Riel