From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Michael S. Tsirkin" Subject: Re: Possible to backport this vhost-net fix to 3.10? Date: Sat, 4 Oct 2014 21:35:08 +0300 Message-ID: <20141004183508.GA15194@redhat.com> References: <542F3370.1090405@ehuk.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: kvm@vger.kernel.org, Romain Francoise , Michael Mueller To: Eddie Chapman Return-path: Received: from mx1.redhat.com ([209.132.183.28]:53010 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750928AbaJDScB (ORCPT ); Sat, 4 Oct 2014 14:32:01 -0400 Content-Disposition: inline In-Reply-To: <542F3370.1090405@ehuk.net> Sender: kvm-owner@vger.kernel.org List-ID: On Sat, Oct 04, 2014 at 12:38:24AM +0100, Eddie Chapman wrote: > Hi, > > I've been regularly seeing on the 3.10 stable kernels the same problem as > reported by Romain Francoise here: > https://lkml.org/lkml/2013/1/23/492 > > An example from my setup is at the bottom of this mail. It's a problem as > qemu fails to run when it hits this, only solution is to do all qemu > launches with vhost=off after it happens. It starts happening after the > machine has been running for a while and after a few VMs have been started. > I guess that is the fragmentation issue as the machine is never under any > serious memory pressure when it happens. > > I see this set of changes for 3.16 has a couple of fixes which appear to > address the problem: > https://lkml.org/lkml/2014/6/11/302 > > I was just wondering if there are any plans to backport these to 3.10, or > even if it is actually possible (I'm not a kernel dev so wouldn't know)? > > If not, are there any other workarounds other than vhost=off? > > thanks, > Eddie Yes, these patches aren't hard to backport. Go ahead and post the backport, I'll review and ack. > [1948751.794040] qemu-system-x86: page allocation failure: order:4, > mode:0x1040d0 > [1948751.810341] CPU: 4 PID: 41198 Comm: qemu-system-x86 Not tainted > 3.10.53-rc1 #3 > [1948751.826846] Hardware name: Intel Corporation S1200BTL/S1200BTL, BIOS > S1200BT.86B.02.00.0041.120520121743 12/05/2012 > [1948751.847285] 0000000000000004 ffff8802eaf3b9d8 ffffffff8162ff4d > ffff8802eaf3ba68 > [1948751.864257] ffffffff810ab771 0000000000000001 ffff8802eaf3bb48 > ffff8802eaf3ba68 > [1948751.881209] ffffffff810abe68 ffffffff81ca2f40 ffffffff00000000 > 0000000200000040 > [1948751.898276] Call Trace: > [1948751.909628] [] dump_stack+0x19/0x1c > [1948751.924284] [] warn_alloc_failed+0x111/0x126 > [1948751.939774] [] ? > __alloc_pages_direct_compact+0x181/0x198 > [1948751.956650] [] __alloc_pages_nodemask+0x72f/0x77c > [1948751.972853] [] __get_free_pages+0x12/0x41 > [1948751.988297] [] vhost_net_open+0x23/0x171 [vhost_net] > [1948752.004938] [] misc_open+0x119/0x17d > [1948752.020111] [] chrdev_open+0x134/0x155 > [1948752.035604] [] ? lg_local_unlock+0x1e/0x31 > [1948752.051436] [] ? cdev_put+0x24/0x24 > [1948752.066540] [] do_dentry_open+0x15c/0x20f > [1948752.082214] [] finish_open+0x34/0x3f > [1948752.097234] [] do_last+0x996/0xbcb > [1948752.111983] [] ? link_path_walk+0x5e/0x791 > [1948752.127447] [] ? path_init+0x11d/0x403 > [1948752.142517] [] path_openat+0xc6/0x43b > [1948752.157207] [] ? __lock_acquire+0x9ae/0xa4a > [1948752.172369] [] ? rtnl_unlock+0x9/0xb > [1948752.186893] [] do_filp_open+0x38/0x84 > [1948752.201503] [] ? _raw_spin_unlock+0x26/0x2a > [1948752.216719] [] ? __alloc_fd+0xf6/0x10a > [1948752.231521] [] do_sys_open+0x114/0x1a6 > [1948752.246396] [] SyS_open+0x19/0x1b > [1948752.260709] [] system_call_fastpath+0x16/0x1b