Kernel oops with night backups

[erjotek]

Hello, this is my first post.

Could someone explain to me why when I do night backup my proxmox server gets oops?
Noticeable are the losses to the virtual machine and host loadavg increases from ~0.2 to ~5

Kernel oops:

vhost: page allocation failure. order:3, mode:0x4020
Pid: 3093, comm: vhost Not tainted 2.6.35-1-pve #1
Call Trace:
<IRQ> [<ffffffff810dbfa6>] __alloc_pages_nodemask+0x5fa/0x678
[<ffffffff8140ae11>] ? nf_iterate+0x48/0x85
[<ffffffff81104d22>] alloc_pages_current+0xad/0xd6
[<ffffffff810daea6>] __get_free_pages+0xe/0x3d
[<ffffffff8110c6a1>] __kmalloc+0x4a/0x146
[<ffffffffa019617a>] ? NF_HOOK+0x42/0x53 [bridge]
[<ffffffff813e06b6>] pskb_expand_head+0x58/0x17c
[<ffffffffa019b1a7>] ? NF_HOOK_THRESH+0x4b/0x52 [bridge]
[<ffffffffa019b429>] ? nf_bridge_push_encap_header+0x34/0x41 [bridge]
[<ffffffffa019c382>] nf_bridge_copy_header+0xae/0x104 [bridge]
[<ffffffffa019642c>] br_dev_queue_push_xmit+0x5f/0x8b [bridge]
[<ffffffffa019b371>] ? br_nf_dev_queue_xmit+0x0/0x84 [bridge]
[<ffffffffa019b3f3>] br_nf_dev_queue_xmit+0x82/0x84 [bridge]
[<ffffffffa019b1a7>] NF_HOOK_THRESH+0x4b/0x52 [bridge]
[<ffffffffa019b14f>] ? nf_bridge_pull_encap_header+0x34/0x41 [bridge]
[<ffffffffa019b35a>] br_nf_post_routing+0x1ac/0x1c3 [bridge]
[<ffffffffa01962b6>] ? br_forward_finish+0x0/0x2a [bridge]
[<ffffffff8140ae11>] nf_iterate+0x48/0x85
[<ffffffffa01963cd>] ? br_dev_queue_push_xmit+0x0/0x8b [bridge]
[<ffffffff8140aeb6>] nf_hook_slow+0x68/0xc8
[<ffffffffa01963cd>] ? br_dev_queue_push_xmit+0x0/0x8b [bridge]
[<ffffffffa01963cd>] ? br_dev_queue_push_xmit+0x0/0x8b [bridge]
[<ffffffffa019617a>] NF_HOOK+0x42/0x53 [bridge]
[<ffffffffa01962b6>] ? br_forward_finish+0x0/0x2a [bridge]
[<ffffffffa01962b6>] ? br_forward_finish+0x0/0x2a [bridge]
[<ffffffffa01962de>] br_forward_finish+0x28/0x2a [bridge]
[<ffffffffa019b1a7>] NF_HOOK_THRESH+0x4b/0x52 [bridge]
[<ffffffffa019b429>] ? nf_bridge_push_encap_header+0x34/0x41 [bridge]
[<ffffffffa019b5d1>] br_nf_forward_finish+0xb8/0xc2 [bridge]
[<ffffffffa019b519>] ? br_nf_forward_finish+0x0/0xc2 [bridge]
[<ffffffffa019b1a7>] NF_HOOK_THRESH+0x4b/0x52 [bridge]
[<ffffffffa019b14f>] ? nf_bridge_pull_encap_header+0x34/0x41 [bridge]
[<ffffffffa019b84a>] br_nf_forward_ip+0x1e0/0x1fd [bridge]
[<ffffffff8140ae11>] nf_iterate+0x48/0x85
[<ffffffffa01962b6>] ? br_forward_finish+0x0/0x2a [bridge]
[<ffffffff8140aeb6>] nf_hook_slow+0x68/0xc8
[<ffffffffa01962b6>] ? br_forward_finish+0x0/0x2a [bridge]
[<ffffffffa01962b6>] ? br_forward_finish+0x0/0x2a [bridge]
[<ffffffffa019617a>] NF_HOOK+0x42/0x53 [bridge]
[<ffffffffa0196204>] __br_forward+0x79/0x7d [bridge]
[<ffffffffa0196242>] br_forward+0x3a/0x4d [bridge]
[<ffffffffa019722b>] br_handle_frame_finish+0x155/0x1ce [bridge]
[<ffffffffa01970d6>] ? br_handle_frame_finish+0x0/0x1ce [bridge]
[...]
[<ffffffff8106ab66>] ? kthread+0x0/0x8a
[<ffffffff8100ab20>] ? kernel_thread_helper+0x0/0x10
Mem-Info:
Node 0 DMA per-cpu:
CPU 0: hi: 0, btch: 1 usd: 0
CPU 1: hi: 0, btch: 1 usd: 0
CPU 2: hi: 0, btch: 1 usd: 0
CPU 3: hi: 0, btch: 1 usd: 0
CPU 4: hi: 0, btch: 1 usd: 0
CPU 5: hi: 0, btch: 1 usd: 0
CPU 6: hi: 0, btch: 1 usd: 0
CPU 7: hi: 0, btch: 1 usd: 0
Node 0 DMA32 per-cpu:
CPU 0: hi: 186, btch: 31 usd: 0
CPU 1: hi: 186, btch: 31 usd: 0
CPU 2: hi: 186, btch: 31 usd: 0
CPU 3: hi: 186, btch: 31 usd: 0
CPU 4: hi: 186, btch: 31 usd: 0
CPU 5: hi: 186, btch: 31 usd: 0
CPU 6: hi: 186, btch: 31 usd: 2
CPU 7: hi: 186, btch: 31 usd: 1
Node 0 Normal per-cpu:
CPU 0: hi: 186, btch: 31 usd: 0
CPU 1: hi: 186, btch: 31 usd: 0
CPU 2: hi: 186, btch: 31 usd: 0
CPU 3: hi: 186, btch: 31 usd: 0
CPU 4: hi: 186, btch: 31 usd: 0
CPU 5: hi: 186, btch: 31 usd: 0
CPU 6: hi: 186, btch: 31 usd: 0
CPU 7: hi: 186, btch: 31 usd: 0
active_anon:2060414 inactive_anon:220934 isolated_anon:0
active_file:538725 inactive_file:990383 isolated_file:34
unevictable:1270 dirty:457571 writeback:55 unstable:0
free:22702 slab_reclaimable:123566 slab_unreclaimable:14400
mapped:3174 shmem:198 pagetables:7213 bounce:0
Node 0 DMA free:15772kB min:12kB low:12kB high:16kB active_anon:0kB inactive_anon:0kB active_file:0kB inactive_file:0kB unevictable:0kB isolated(anon):0kB isolated(file):0kB present:15656kB mlocked:0kB dirty:0kB writeback:0kB mapped:0kB shmem:0kB slab_reclaimable:0kB slab_unreclaimable:16kB kernel_stack:0kB pagetables:0kB unstable:0kB bounce:0kB writeback_tmp:0kB pages_scanned:0 all_unreclaimable? no
lowmem_reserve[]: 0 2992 16096 16096
Node 0 DMA32 free:58288kB min:3016kB low:3768kB high:4524kB active_anon:343540kB inactive_anon:88800kB active_file:744824kB inactive_file:1442776kB unevictable:0kB isolated(anon):0kB isolated(file):0kB present:3063836kB mlocked:0kB dirty:683940kB writeback:48kB mapped:1032kB shmem:0kB slab_reclaimable:345520kB slab_unreclaimable:3252kB kernel_stack:384kB pagetables:76kB unstable:0kB bounce:0kB writeback_tmp:0kB pages_scanned:0 all_unreclaimable? no
lowmem_reserve[]: 0 0 13104 13104
Node 0 Normal free:16748kB min:13208kB low:16508kB high:19812kB active_anon:7898116kB inactive_anon:794936kB active_file:1410076kB inactive_file:2518756kB unevictable:5080kB isolated(anon):0kB isolated(file):136kB present:13418496kB mlocked:5080kB dirty:1146344kB writeback:172kB mapped:11664kB shmem:792kB slab_reclaimable:148744kB slab_unreclaimable:54332kB kernel_stack:2080kB pagetables:28776kB unstable:0kB bounce:0kB writeback_tmp:0kB pages_scanned:0 all_unreclaimable? no
lowmem_reserve[]: 0 0 0 0
Node 0 DMA: 1*4kB 1*8kB 1*16kB 0*32kB 2*64kB 0*128kB 1*256kB 0*512kB 1*1024kB 1*2048kB 3*4096kB = 15772kB
Node 0 DMA32: 14134*4kB 122*8kB 49*16kB 1*32kB 0*64kB 0*128kB 0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB = 58328kB
Node 0 Normal: 3631*4kB 140*8kB 11*16kB 4*32kB 0*64kB 2*128kB 1*256kB 1*512kB 0*1024kB 0*2048kB 0*4096kB = 16972kB
1562283 total pagecache pages
32550 pages in swap cache
Swap cache stats: add 1340546, delete 1307996, find 6446359/6586110
Free swap = 7180096kB
Total swap = 7340028kB
4194288 pages RAM
85013 pages reserved
1519353 pages shared
2587709 pages non-shared

Log from backup:

Jun 30 05:50:51 INFO: Starting Backup of VM 114 (qemu)
Jun 30 05:50:51 INFO: running
Jun 30 05:50:51 INFO: status = running
Jun 30 05:50:52 INFO: backup mode: snapshot
Jun 30 05:50:52 INFO: ionice priority: 7
Jun 30 05:50:52 INFO: suspend vm to make snapshot
Jun 30 05:50:52 INFO: Logical volume "vzsnap-virt1-0" created
Jun 30 05:50:52 INFO: Logical volume "vzsnap-virt1-1" created
Jun 30 05:50:52 INFO: resume vm
Jun 30 05:50:53 INFO: vm is online again after 1 seconds
Jun 30 05:50:53 INFO: creating archive '/var/lib/vz/dump/vzdump-qemu-114-2011_06_30-05_50_51.tar'
Jun 30 05:50:53 INFO: adding '/var/lib/vz/dump/vzdump-qemu-114-2011_06_30-05_50_51.tmp/qemu-server.conf' to archive ('qemu-server.conf')
Jun 30 05:50:53 INFO: adding '/dev/pveiscsi/vzsnap-virt1-0' to archive ('vm-disk-virtio0.raw')
Jun 30 06:13:34 INFO: adding '/dev/pveiscsi/vzsnap-virt1-1' to archive ('vm-disk-virtio1.raw')
Jun 30 06:36:30 INFO: Total bytes written: 45262381056 (15.77 MiB/s)
Jun 30 06:36:30 INFO: archive file size: 42.15GB
Jun 30 06:36:30 INFO: delete old backup '/var/lib/vz/dump/vzdump-qemu-114-2011_06_29-04_24_55.tar'
Jun 30 06:37:07 INFO: Logical volume "vzsnap-virt1-0" successfully removed
Jun 30 06:37:07 INFO: /dev/dm-30: stat failed: No such file or directory
Jun 30 06:37:07 INFO: Path /dev/dm-30 no longer valid for device(251,30)
Jun 30 06:37:07 INFO: /dev/block/251:30: stat failed: No such file or directory
Jun 30 06:37:07 INFO: Path /dev/block/251:30 no longer valid for device(251,30)
Jun 30 06:37:08 INFO: Logical volume "vzsnap-virt1-1" successfully removed
Jun 30 06:37:09 INFO: Finished Backup of VM 114 (00:46:18)

Config:
ostype: l26
memory: 512
sockets: 2
onboot: 1
name: Documents
boot: c
acpi: 1
kvm: 1
args: -balloon virtio -cpu host
cores: 1
freeze: 0
cpuunits: 1000
virtio0: v1lvm:vm-105-disk-1,cache=none
vlan0: virtio=D6:FA:50:15:59:21
ide1: local:iso/systemrescuecd-x86-1.6.3.iso,media=cdrom
bootdisk: virtio0
virtio1: v1lvm:vm-105-disk-2


# pveversion -v
pve-manager: 1.8-18 (pve-manager/1.8/6070)
running kernel: 2.6.35-1-pve
proxmox-ve-2.6.35: 1.8-11
pve-kernel-2.6.35-1-pve: 2.6.35-11
qemu-server: 1.1-30
pve-firmware: 1.0-11
libpve-storage-perl: 1.0-17
vncterm: 0.9-2
vzctl: 3.0.27-1pve1
vzdump: 1.2-13
vzprocps: 2.0.11-2
vzquota: 3.0.11-1
pve-qemu-kvm: 0.14.1-1
ksm-control-daemon: 1.0-6