OOM when adding ipv6 route: How to make available more per-cpu memory?

Ben Greear
2010-11-05T17:19:07Z

We are testing 500 mac-vlans with IPv6 addresses on a 32-bit kernel
(2.6.36 + ubuntu patches + our patches) We have one
routing table per interface. It seems that some of them cannot
add routes due to lack of memory.

root@lanforge-ubuntu:/home/lanforge# ip route show table 29
root@lanforge-ubuntu:/home/lanforge# ./local/sbin/ip -6 route add default via 2001:98::1 dev eth12#15 table 29
RTNETLINK answers: Cannot allocate memory

I see errors such as this in the logs:

[507107.846864] PERCPU: allocation failed, size=2048 align=4, failed to allocate new chunk
[507107.846867] Pid: 3246, comm: ip Tainted: P 2.6.36-1-ct #7
[507107.846869] Call Trace:
[507107.846874] [<c05d4996>] ? printk+0x2d/0x2f
[507107.846878] [<c021405e>] pcpu_alloc+0x32e/0x360
[507107.846880] [<c02140bf>] __alloc_percpu+0xf/0x20
[507107.846883] [<c0558d6d>] snmp_mib_init+0x3d/0x70
[507107.846885] [<c0585692>] ipv6_add_dev+0x132/0x350
[507107.846887] [<c0557f39>] ? inetdev_init+0xb9/0x180
[507107.846889] [<c05895ff>] addrconf_notify+0x3f/0x490
[507107.846891] [<c055884f>] ? inetdev_event+0x20f/0x280
[507107.846894] [<c05daef3>] notifier_call_chain+0x43/0x60
[507107.846897] [<c016df4f>] raw_notifier_call_chain+0x1f/0x30
[507107.846899] [<c05008ec>] call_netdevice_notifiers+0x2c/0x60
[507107.846901] [<c0502ecc>] register_netdevice+0x23c/0x380
[507107.846907] [<f80aecf7>] macvlan_common_newlink+0x187/0x2a0 [macvlan]
[507107.846910] [<f80ae540>] ? macvlan_setup+0x0/0x20 [macvlan]
[507107.846912] [<f80aee37>] macvlan_newlink+0x27/0x30 [macvlan]
[507107.846914] [<c0503060>] ? netif_rx+0x0/0x120
[507107.846915] [<c05033c0>] ? dev_forward_skb+0x0/0xf0
[507107.846917] [<f80aee10>] ? macvlan_newlink+0x0/0x30 [macvlan]
[507107.846920] [<c050ea94>] rtnl_newlink+0x464/0x590
[507107.846921] [<c050e7e6>] ? rtnl_newlink+0x1b6/0x590
[507107.846927] [<c050cd2d>] rtnetlink_rcv_msg+0x13d/0x230
[507107.846929] [<c05d721f>] ? _raw_spin_lock_irqsave+0x2f/0x50
[507107.846931] [<c050e630>] ? rtnl_newlink+0x0/0x590
[507107.846933] [<c050cbf0>] ? rtnetlink_rcv_msg+0x0/0x230
[507107.846935] [<c0522276>] netlink_rcv_skb+0x86/0xb0
[507107.846936] [<c050cbdc>] rtnetlink_rcv+0x1c/0x30
[507107.846938] [<c0521f69>] netlink_unicast+0x259/0x280
[507107.846940] [<c0522ba8>] netlink_sendmsg+0x1f8/0x300
[507107.846943] [<c04f0b79>] sock_sendmsg+0xd9/0x100
[507107.846945] [<c013e0dd>] ? finish_task_switch+0x3d/0xc0
[507107.846947] [<c04f0b79>] ? sock_sendmsg+0xd9/0x100
[507107.846950] [<c013361d>] ? kmap_atomic_prot+0xcd/0xf0
[507107.846957] [<f88bd559>] ? h_d_revalidate+0xe9/0x240 [aufs]
[507107.846958] [<c013361d>] ? kmap_atomic_prot+0xcd/0xf0
[507107.846962] [<c0364c7d>] ? _copy_from_user+0x3d/0x130
[507107.846965] [<c04f947a>] ? verify_iovec+0x5a/0xa0
[507107.846966] [<c04f112d>] sys_sendmsg+0x15d/0x290
[507107.846972] [<f88c05f1>] ? aufs_fault+0xf1/0x110 [aufs]
[507107.846974] [<c013361d>] ? kmap_atomic_prot+0xcd/0xf0
[507107.846977] [<c01f8726>] ? handle_mm_fault+0x146/0x400
[507107.846979] [<c05dac0d>] ? do_page_fault+0x1cd/0x470
[507107.846981] [<c023419d>] ? alloc_fd+0xbd/0xf0
[507107.846983] [<c0364c7d>] ? _copy_from_user+0x3d/0x130
[507107.846986] [<c04f183b>] sys_socketcall+0xeb/0x2a0
[507107.846989] [<c0151d99>] ? irq_exit+0x39/0x70
[507107.846991] [<c021bb2e>] ? sys_open+0x2e/0x40
[507107.846993] [<c05d77a4>] syscall_call+0x7/0xb

But, it appears to me that we have plenty of memory available.

top - 10:09:13 up 6 days, 15:56, 9 users, load average: 0.37, 0.39, 0.45
Tasks: 211 total, 2 running, 209 sleeping, 0 stopped, 0 zombie
Cpu(s): 0.7%us, 2.1%sy, 0.0%ni, 97.2%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
Mem: 3604332k total, 1510252k used, 2094080k free, 84928k buffers
Swap: 154620k total, 0k used, 154620k free, 1045912k cached

PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND

root@lanforge-ubuntu:/home/lanforge# cat /proc/meminfo
MemTotal: 3604332 kB
MemFree: 2094568 kB
Buffers: 84928 kB
Cached: 1045920 kB
SwapCached: 0 kB
Active: 466784 kB
Inactive: 805632 kB
Active(anon): 148988 kB
Inactive(anon): 6788 kB
Active(file): 317796 kB
Inactive(file): 798844 kB
Unevictable: 0 kB
Mlocked: 0 kB
HighTotal: 2752008 kB
HighFree: 1512380 kB
LowTotal: 852324 kB
LowFree: 582188 kB
SwapTotal: 154620 kB
SwapFree: 154620 kB
Dirty: 492 kB
Writeback: 0 kB
AnonPages: 141316 kB
Mapped: 39428 kB
Shmem: 14208 kB
Slab: 170788 kB
SReclaimable: 81904 kB
SUnreclaim: 88884 kB
KernelStack: 2520 kB
PageTables: 4516 kB
NFS_Unstable: 0 kB
Bounce: 0 kB
WritebackTmp: 0 kB
CommitLimit: 1956784 kB
Committed_AS: 582604 kB
VmallocTotal: 122880 kB
VmallocUsed: 48592 kB
VmallocChunk: 24280 kB
HardwareCorrupted: 0 kB
HugePages_Total: 0
HugePages_Free: 0
HugePages_Rsvd: 0
HugePages_Surp: 0
Hugepagesize: 4096 kB
DirectMap4k: 12280 kB
DirectMap4M: 897024 kB

Is there any way to tune the system so that it has more memory available
for per-cpu data structures?

Thanks,
Ben

--
Ben Greear <greearb@candelatech.com>
Candela Technologies Inc http://www.candelatech.com