Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762367AbXJOVut (ORCPT ); Mon, 15 Oct 2007 17:50:49 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1758397AbXJOVtP (ORCPT ); Mon, 15 Oct 2007 17:49:15 -0400 Received: from zrnetservice.com ([209.133.52.163]:33159 "EHLO wifi.zrnetservice.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1756819AbXJOVtI (ORCPT ); Mon, 15 Oct 2007 17:49:08 -0400 Message-Id: <20071015210115.506967748@goop.org> References: <20071015204840.074767068@goop.org> User-Agent: quilt/0.46-1 Date: Mon, 15 Oct 2007 13:48:52 -0700 From: Jeremy Fitzhardinge To: Linus Torvalds Cc: LKML , Andi Kleen , Andrew Morton , virtualization@lists.osdl.org, xen-devel@lists.xensource.com, Chris Wright , Keir Fraser , Stable Kernel , David Chinner , Nick Piggin , XFS masters , Morten =?utf-8?q?B=C3=B8geskov?= , Mark Williamson Subject: [PATCH 12/12] xfs: eagerly remove vmap mappings to avoid upsetting Xen Content-Disposition: inline; filename=xen-xfs-unmap.patch Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1831 Lines: 53 XFS leaves stray mappings around when it vmaps memory to make it virtually contigious. This upsets Xen if one of those pages is being recycled into a pagetable, since it finds an extra writable mapping of the page. This patch solves the problem in a brute force way, by making XFS always eagerly unmap its mappings. David Chinner says this shouldn't have any performance impact on filesystems with default block sizes; it will only affect filesystems with large block sizes. Signed-off-by: Jeremy Fitzhardinge Cc: David Chinner Cc: Nick Piggin Cc: XFS masters Cc: Stable kernel Cc: Morten =?utf-8?q?B=C3=B8geskov?= Cc: Mark Williamson --- fs/xfs/linux-2.6/xfs_buf.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) =================================================================== --- a/fs/xfs/linux-2.6/xfs_buf.c +++ b/fs/xfs/linux-2.6/xfs_buf.c @@ -186,6 +186,19 @@ free_address( void *addr) { a_list_t *aentry; + +#ifdef CONFIG_XEN + /* + * Xen needs to be able to make sure it can get an exclusive + * RO mapping of pages it wants to turn into a pagetable. If + * a newly allocated page is also still being vmap()ed by xfs, + * it will cause pagetable construction to fail. This is a + * quick workaround to always eagerly unmap pages so that Xen + * is happy. + */ + vunmap(addr); + return; +#endif aentry = kmalloc(sizeof(a_list_t), GFP_NOWAIT); if (likely(aentry)) { -- - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/