From mboxrd@z Thu Jan 1 00:00:00 1970 Subject: Re: [kvm-devel] [PATCH] export notifier #1 From: Benjamin Herrenschmidt Reply-To: benh@kernel.crashing.org In-Reply-To: References: <20080113162418.GE8736@v2.random> <20080116124256.44033d48@bree.surriel.com> <478E4356.7030303@qumranet.com> <20080117162302.GI7170@v2.random> <478F9C9C.7070500@qumranet.com> <20080117193252.GC24131@v2.random> <20080121125204.GJ6970@v2.random> <4795F9D2.1050503@qumranet.com> <20080122144332.GE7331@v2.random> <20080122200858.GB15848@v2.random> Content-Type: text/plain Date: Wed, 23 Jan 2008 10:36:29 +1100 Message-Id: <1201044989.6807.46.camel@pasglop> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Christoph Lameter Cc: Andrea Arcangeli , Avi Kivity , Izik Eidus , Andrew Morton , Nick Piggin , kvm-devel@lists.sourceforge.net, steiner@sgi.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, daniel.blueman@quadrics.com, holt@sgi.com, Hugh Dickins List-ID: On Tue, 2008-01-22 at 12:34 -0800, Christoph Lameter wrote: > > - Notifiers are called *after* we tore down ptes. At that point pages > may already have been freed and reused. This means that there can > still be uses of the page by the user of mmu_ops after the OS has > dropped its mapping. IMHO the foreign entity needs to drop its > mappings first. That also ensures that the entities operated > upon continue to exist. That's definitely an issue. Maybe having the foreign entity get a reference to the page and drop it when it unmaps would help ? > - anon_vma/inode and pte locks are held during callbacks. So how does that fix the problem of sleeping then ? Ben. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org