R.A. Epigonos et al.

[linux] swapper: page allocation failureを解決するにはvm.min_free_kbytesを設定

dmesgにswapper: page allocation failure.というエラーらしきものが表示されるようになった。どうやら、ネットワークでビットレートの高い高速通信をしている場合におきるような傾向がある。

dmesgに見えるエラーは以下のような感じ。

[ 7873.855883] swapper: page allocation failure. order:0, mode:0x20
[ 7873.855895] Pid: 0, comm: swapper Not tainted 2.6.32-5-686 #1
[ 7873.855899] Call Trace:
[ 7873.855935]  [<c108c9a2>] ? __alloc_pages_nodemask+0x484/0x4d9
[ 7873.855945]  [<c10ae77e>] ? alloc_slab_page+0x18/0x1b
[ 7873.855951]  [<c10ae8c0>] ? __slab_alloc+0x13f/0x431
[ 7873.855958]  [<c10aed44>] ? kmem_cache_alloc+0x6d/0xe5
[ 7873.855968]  [<c11d3f19>] ? __alloc_skb+0x29/0x115
[ 7873.855974]  [<c11d3f19>] ? __alloc_skb+0x29/0x115
[ 7873.855980]  [<c11d3f19>] ? __alloc_skb+0x29/0x115
[ 7873.855987]  [<c11d4cc4>] ? __netdev_alloc_skb+0x14/0x30
[ 7873.856023]  [<d0a59a08>] ? e100_rx_alloc_skb+0x1e/0x11d [e100]
[ 7873.856035]  [<d0a5bbb1>] ? e100_poll+0x1d6/0x29d [e100]
[ 7873.856056]  [<c11da231>] ? net_rx_action+0x96/0x194
[ 7873.856070]  [<c1035a96>] ? __do_softirq+0xaa/0x156
[ 7873.856077]  [<c1035b73>] ? do_softirq+0x31/0x3c
[ 7873.856083]  [<c1035c4d>] ? irq_exit+0x26/0x58
[ 7873.856101]  [<c1004699>] ? do_IRQ+0x78/0x89
[ 7873.856108]  [<c10037f0>] ? common_interrupt+0x30/0x38
[ 7873.856133]  [<c101aacc>] ? native_safe_halt+0x2/0x3
[ 7873.856143]  [<c1008813>] ? default_idle+0x3c/0x5a
[ 7873.856149]  [<c1002377>] ? cpu_idle+0x89/0xa2
[ 7873.856169]  [<c13bf7fc>] ? start_kernel+0x318/0x31d
[ 7873.856174] Mem-Info:
[ 7873.856178] DMA per-cpu:
[ 7873.856182] CPU    0: hi:    0, btch:   1 usd:   0
[ 7873.856185] Normal per-cpu:
[ 7873.856189] CPU    0: hi:   90, btch:  15 usd:  89
[ 7873.856200] active_anon:762 inactive_anon:827 isolated_anon:0
[ 7873.856202]  active_file:28611 inactive_file:28682 isolated_file:0
[ 7873.856205]  unevictable:0 dirty:1 writeback:0 unstable:0
[ 7873.856207]  free:427 slab_reclaimable:774 slab_unreclaimable:2329
[ 7873.856209]  mapped:8735 shmem:0 pagetables:234 bounce:0
[ 7873.856226] DMA free:992kB min:124kB low:152kB high:184kB active_anon:64kB inactive_anon:116kB active_file:7056kB inactive_file:7328kB unevictable:0kB isolated(anon):0kB isolated(file):0kB present:15872kB mlocked:0kB dirty:0kB writeback:0kB mapped:1796kB shmem:0kB slab_reclaimable:76kB slab_unreclaimable:292kB kernel_stack:8kB pagetables:16kB unstable:0kB bounce:0kB writeback_tmp:0kB pages_scanned:0 all_unreclaimable? no
[ 7873.856237] lowmem_reserve[]: 0 238 238 238
[ 7873.856251] Normal free:716kB min:1908kB low:2384kB high:2860kB active_anon:2984kB inactive_anon:3192kB active_file:107388kB inactive_file:107400kB unevictable:0kB isolated(anon):0kB isolated(file):0kB present:243776kB mlocked:0kB dirty:8kB writeback:0kB mapped:33144kB shmem:0kB slab_reclaimable:3020kB slab_unreclaimable:9024kB kernel_stack:640kB pagetables:920kB unstable:0kB bounce:0kB writeback_tmp:0kB pages_scanned:86 all_unreclaimable? no
[ 7873.856262] lowmem_reserve[]: 0 0 0 0
[ 7873.856268] DMA: 0*4kB 2*8kB 1*16kB 0*32kB 5*64kB 1*128kB 2*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB = 992kB
[ 7873.856284] Normal: 179*4kB 0*8kB 0*16kB 0*32kB 0*64kB 0*128kB 0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB = 716kB
[ 7873.856300] 57660 total pagecache pages
[ 7873.856304] 363 pages in swap cache
[ 7873.856308] Swap cache stats: add 13396, delete 13033, find 2464/3626
[ 7873.856312] Free swap  = 346240kB
[ 7873.856315] Total swap = 369452kB
[ 7873.859847] 65520 pages RAM
[ 7873.859847] 0 pages HighMem
[ 7873.859847] 1858 pages reserved
[ 7873.859847] 20298 pages shared
[ 7873.859847] 50296 pages non-shared
[ 7873.859847] SLUB: Unable to allocate memory on node -1 (gfp=0x20)
[ 7873.859847]   cache: kmalloc-192, object size: 192, buffer size: 192, default order: 0, min order: 0
[ 7873.859847]   node 0: slabs: 105, objs: 2205, free: 0

ページキャッシュが開放されるタイミングを左右するパラメータが小さすぎる(物理メモリの空きがvm.min_free_kbytesの設定値を下回るとページキャッシュが開放される)ことが問題。まずはこのパラメータに設定された値を確認。先のエラーが生じた物理メモリ256MBのマシンで確認。デフォルトの計算式に従うなら、4 * sqrt(256E+3) = 2 023.8577 で大体同じくらい。

# sysctl vm.min_free_kbytes
vm.min_free_kbytes = 2038
# cat /proc/sys/vm/min_free_kbytes
2038

エラーが生じていない物理メモリ1024MBのマシンで確認。デフォルトの計算式に従うなら、4 * sqrt(1024E+3) = 4047.71541 だけど、ちょっと違う。

# sysctl vm.min_free_kbytes
vm.min_free_kbytes = 3789
# cat /proc/sys/vm/min_free_kbytes
3789

一時的に変えるには、echoで書き込む。ここでは4096 KBを設定。

# echo 4096 > /proc/sys/vm/min_free_kbytes
# sysctl vm.min_free_kbytes
vm.min_free_kbytes = 4096
# cat /proc/sys/vm/min_free_kbytes
4096

恒久的、永続的に変えるには、/etc/sysctl.conf または /etc/sysctl.d/*.conf を編集。ここでは 4096 KBを設定。編集後に sysctl -p を忘れずに。

# echo vm.min_free_kbytes=4096 >> /etc/sysctl.d/local.conf
# sysctl -p
net.ipv4.ip_forward = 1
vm.min_free_kbytes = 4096

リファレンス

  1. swapper: page allocation failure - Google 検索
  2. page allocation failure - 気まぐれSE日記
  3. SUZAKUでカーネルパニック起きた. - minovel_mskの日記
  4. Twitter / hirokikawaguchi: kernel 2.6.32-131.0.15.el6
  5. "swapper: page allocation failure" vm.min_free_kbytes - Google 検索
  6. Linux page allocation failures — reading the fine print | Lifting the Earth using Linux
  7. cannot allocate memory error
  8. http://www.acc.umu.se/~maswan/linux-netperf.txt
  9. Re: swapper: page allocation failure. order:1, mode:0x20
  10. Re: swapper: page allocation failure. order:3, mode:0x20
  11. 5.4. Using the sysctl Command
  12. /proc/sys/vm/min_free_kbytes - Google 検索
  13. hollyなblog:サーバ負荷基準 その3
  14. kernel:Memory Manage(2) min_free_kbytes - Simple is Beautiful
  15. openSUSE 12.2: 第15章 メモリ管理サブシステムのチューニング
  16. Linux/kernelチューニング - Nobuhito Mori
  17. Linux関連メモ - (linux) カーネルチューニング_メモリ
  18. sysctl "-p" sysctl.conf - Google 検索
  19. [ThinkIT] 第5回:カーネルをチューニングする (1/4)
  20. Man page of SYSCTL

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ChangeLog

  1. Posted: 2010-06-17T21:19:45+09:00
  2. Modified: 2010-06-17T21:19:45+09:00
  3. Generated: 2023-08-27T23:09:15+09:00