From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Wed, 12 Nov 2008 14:27:42 -0600 (CST) From: Christoph Lameter Subject: Re: [PATCH 2/4] Add replace_page(), change the mapping of pte from one page into another In-Reply-To: <20081112173258.GX10818@random.random> Message-ID: References: <1226409701-14831-3-git-send-email-ieidus@redhat.com> <20081111114555.eb808843.akpm@linux-foundation.org> <20081111210655.GG10818@random.random> <20081111221753.GK10818@random.random> <20081111231722.GR10818@random.random> <20081112022701.GT10818@random.random> <20081112173258.GX10818@random.random> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org Return-Path: To: Andrea Arcangeli Cc: Andrew Morton , Izik Eidus , linux-kernel@vger.kernel.org, linux-mm@kvack.org, kvm@vger.kernel.org, chrisw@redhat.com, avi@redhat.com, izike@qumranet.com List-ID: On Wed, 12 Nov 2008, Andrea Arcangeli wrote: > On Tue, Nov 11, 2008 at 09:10:45PM -0600, Christoph Lameter wrote: > > get_user_pages() cannot get to it since the pagetables have already been > > modified. If get_user_pages runs then the fault handling will occur > > which will block the thread until migration is complete. > > migrate.c does nothing for ptes pointing to swap entries and > do_swap_page won't wait for them either. Assume follow_page in If a anonymous page is a swap page then it has a mapping. migrate_page_move_mapping() will lock the radix tree and ensure that no additional reference (like done by do_swap_page) is established during migration. > However it's not exactly the same bug as the one in fork, I was > talking about before, it's also not o_direct specific. Still So far I have seen wild ideas not bugs. -- 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