From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755581AbaCOTZq (ORCPT ); Sat, 15 Mar 2014 15:25:46 -0400 Received: from mx1.redhat.com ([209.132.183.28]:1108 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750900AbaCOTZp (ORCPT ); Sat, 15 Mar 2014 15:25:45 -0400 Message-ID: <5324A92A.3040309@redhat.com> Date: Sat, 15 Mar 2014 15:25:30 -0400 From: Rik van Riel User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.2.0 MIME-Version: 1.0 To: "Aneesh Kumar K.V" , benh@kernel.crashing.org, paulus@samba.org CC: linuxppc-dev@lists.ozlabs.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] powerpc/mm: Make sure a local_irq_disable prevent a parallel THP split References: <1394880478-770-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com> In-Reply-To: <1394880478-770-1-git-send-email-aneesh.kumar@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 On 03/15/2014 06:47 AM, Aneesh Kumar K.V wrote: > From: "Aneesh Kumar K.V" > > We have generic code like the one in get_futex_key that assume that > a local_irq_disable prevents a parallel THP split. Support that by > adding a dummy smp call function after setting _PAGE_SPLITTING. Code > paths like get_user_pages_fast still need to check for _PAGE_SPLITTING > after disabling IRQ which indicate that a parallel THP splitting is > ongoing. Now if they don't find _PAGE_SPLITTING set, then we can be > sure that parallel split will now block in pmdp_splitting flush > until we enables IRQ > > Signed-off-by: Aneesh Kumar K.V Acked-by: Rik van Riel -- All rights reversed