From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eddie Chapman Subject: Possible to backport this vhost-net fix to 3.10? Date: Sat, 04 Oct 2014 00:38:24 +0100 Message-ID: <542F3370.1090405@ehuk.net> Reply-To: Eddie Chapman Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Cc: Romain Francoise , "Michael S. Tsirkin" , Michael Mueller To: kvm@vger.kernel.org Return-path: Received: from mail.steelbluetech.co.uk ([109.169.51.66]:38672 "EHLO mail.steelbluetech.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932316AbaJCXrE (ORCPT ); Fri, 3 Oct 2014 19:47:04 -0400 Sender: kvm-owner@vger.kernel.org List-ID: 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 [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