From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932065AbWC3GaZ (ORCPT ); Thu, 30 Mar 2006 01:30:25 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932069AbWC3GaZ (ORCPT ); Thu, 30 Mar 2006 01:30:25 -0500 Received: from smtp107.mail.mud.yahoo.com ([209.191.85.217]:48032 "HELO smtp107.mail.mud.yahoo.com") by vger.kernel.org with SMTP id S932065AbWC3GaX (ORCPT ); Thu, 30 Mar 2006 01:30:23 -0500 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.com.au; h=Received:Message-ID:Date:From:User-Agent:X-Accept-Language:MIME-Version:To:CC:Subject:References:In-Reply-To:Content-Type:Content-Transfer-Encoding; b=pbR1/8xIV8LnwT9+6Fcm6v7+eMWjNefBMqWPSsm7PLpTp2KUumawxMbHZR0V1piH9z78idt6qYB9Yj7vmWndhntsQFyvqWMm9eVdte8L6WVJ9jmpHoJIG/kLgzkCy3zVBOWpeQe4nS5XA53JmQGkwLK8npkr7L2iuTB+1BLCMqg= ; Message-ID: <442B4EEB.6020407@yahoo.com.au> Date: Thu, 30 Mar 2006 14:22:19 +1100 From: Nick Piggin User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.8) Gecko/20050927 Debian/1.7.8-1sarge3 X-Accept-Language: en MIME-Version: 1.0 To: Luke Yang CC: linux-kernel@vger.kernel.org, Andrew Morton , Nick Piggin Subject: Re: [PATCH] nommu page refcount bug fixing References: <489ecd0c0603291905m7ebffff2j83809cc3c93595f1@mail.gmail.com> In-Reply-To: <489ecd0c0603291905m7ebffff2j83809cc3c93595f1@mail.gmail.com> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Luke Yang wrote: >Hi all, > > The previous "nommu use compound pages" patch has a problem: when >the pages allocated is not compound page (eg: slab allocator), the >refcount value of every page still need to be set, otherwise the >get/put_page() would free a single page improperly, such as in >access_process_vm(). > > Yep, sorry this slipped into the kernel. It's my fault for not giving Andrew a fix for it. As you might know, page refcounting in nommu was already broken, so I'm working on a proper solution to fix it. In the meantime though, this is a step backwards and reintroduces NOMMU special-casing in page refcounting. As a temporary fix, what I think should happen is simply for all slab allocations to ask for __GFP_COMP pages. Could you check that fixes your problem? Thanks, Nick -- Send instant messages to your online friends http://au.messenger.yahoo.com