From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756585AbYJWXsg (ORCPT ); Thu, 23 Oct 2008 19:48:36 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754934AbYJWXsV (ORCPT ); Thu, 23 Oct 2008 19:48:21 -0400 Received: from gw.goop.org ([64.81.55.164]:51036 "EHLO mail.goop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754561AbYJWXsU (ORCPT ); Thu, 23 Oct 2008 19:48:20 -0400 Message-ID: <49010D41.1080305@goop.org> Date: Thu, 23 Oct 2008 16:48:17 -0700 From: Jeremy Fitzhardinge User-Agent: Thunderbird 2.0.0.17 (X11/20081009) MIME-Version: 1.0 To: Nick Piggin CC: Linux Kernel Mailing List , Linux Memory Management List Subject: vm_unmap_aliases and Xen X-Enigmail-Version: 0.95.6 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org I've been having a few problems with Xen, I suspect as a result of the lazy unmapping in vmalloc.c. One immediate one is that vm_unmap_aliases() will oops if you call it before vmalloc_init() is called, which can happen in the Xen case. RFC patch below. But the bigger problem I'm seeing is that despite calling vm_unmap_aliases() at the pertinent places, I'm still seeing errors resulting from stray aliases. Is it possible that vm_unmap_aliases() could be missing some, or not completely synchronous? Subject: vmap: cope with vm_unmap_aliases before vmalloc_init() Xen can end up calling vm_unmap_aliases() before vmalloc_init() has been called. In this case its safe to make it a simple no-op. Signed-off-by: Jeremy Fitzhardinge diff -r 42c8b29f7ccf mm/vmalloc.c --- a/mm/vmalloc.c Wed Oct 22 12:43:39 2008 -0700 +++ b/mm/vmalloc.c Wed Oct 22 21:39:00 2008 -0700 @@ -591,6 +591,8 @@ #define VMAP_BLOCK_SIZE (VMAP_BBMAP_BITS * PAGE_SIZE) +static bool vmap_initialized = false; + struct vmap_block_queue { spinlock_t lock; struct list_head free; @@ -827,6 +829,9 @@ int cpu; int flush = 0; + if (!vmap_initialized) + return; + for_each_possible_cpu(cpu) { struct vmap_block_queue *vbq = &per_cpu(vmap_block_queue, cpu); struct vmap_block *vb; @@ -940,6 +945,8 @@ INIT_LIST_HEAD(&vbq->dirty); vbq->nr_dirty = 0; } + + vmap_initialized = true; } void unmap_kernel_range(unsigned long addr, unsigned long size)