问题
服务器在多次出现“内存不足”消息后崩溃了，我正在尝试找出罪魁祸首。如果它在用户空间中 - 哪个进程。如果它在内核中 - 哪个内核模块。
细节
我正在尝试找出如何使用碰撞实用程序来调查是什么触发了服务器的 OOM。
作为安装一对新服务器的一部分，我开始初始化 14TBDRBD设备。大约在那个时候，在玩 DRBD 同步器速率配置并打开和关闭一些绑定的网络接口时，其中一台服务器崩溃了。在 30 秒内，它产生了 39 条Out of memory: Kill process ####消息。然后它崩溃了：
Kernel panic - not syncing: Out of memory and no killable processes...
系统崩溃引发内核转储。现在我有一个很好的vmcore.flat文件，应该可以直接用它来调查问题，但我很难找出所有内存都去了哪里。
我知道的唯一资源是Dedoimedo 的网站， 其中有很好的说明，以及内核崩溃手册。这些也恰好是答案中建议的唯一资源，所以我认为这crash是唯一的调查方法。
如果有其他方法可以对事件进行事后分析，我愿意接受。只是那是crash我知道的唯一实用程序。我现在只有文件vmcore.flat，我需要知道的是哪个组件占用了所有内存。我怀疑是内核模块问题，更具体地说是绑定模块之一（因为它在我关闭接口时被触发）、DRBD 模块（版本 8.3.15 在 CentOS 6.3 上的树外构建）或 10G 以太网模块之一（在mlnx_en树外构建，即我关闭的接口，或树内构建，bnx2x即保持活动的接口）。我需要知道的只是是否有办法验证我的怀疑。
到目前为止，我仅设法使用以下信息提取了碰撞公用事业：
检查使用了多少内存
$ crash /usr/lib/debug/lib/modules/2.6.32-279.5.2.el6.x86_64/vmlinux vmcore.flat
....
crash> kmem -i
PAGES TOTAL PERCENTAGE
TOTAL MEM 16482587 62.9 GB ----
FREE 54610 213.3 MB 0% of TOTAL MEM
USED 16427977 62.7 GB 99% of TOTAL MEM
SHARED 4683 18.3 MB 0% of TOTAL MEM
BUFFERS 118 472 KB 0% of TOTAL MEM
CACHED 82 328 KB 0% of TOTAL MEM
SLAB 46635 182.2 MB 0% of TOTAL MEM
TOTAL SWAP 0 0 ----
SWAP USED 0 0 100% of TOTAL SWAP
SWAP FREE 0 0 0% of TOTAL SWAP
显然，内存不足了。64G 都没了……但去哪儿了？
尝试查看是否有任何进程正在泄漏内存
唯一看似相关的命令是ps（这是ps的子命令crash）。它没有显示任何异常，但也没有显示任何有关内核线程的信息。
crash> ps
PID PPID CPU TASK ST %MEM VSZ RSS COMM
0 0 0 ffffffff81a8d020 RU 0.0 0 0 [swapper]
> 0 0 1 ffff88102c456040 RU 0.0 0 0 [swapper]
> 0 0 2 ffff88082c772aa0 RU 0.0 0 0 [swapper]
> 0 0 3 ffff88102c456aa0 RU 0.0 0 0 [swapper]
0 0 4 ffff88082c7b8ae0 RU 0.0 0 0 [swapper]
> 0 0 5 ffff88102c457500 RU 0.0 0 0 [swapper]
> 0 0 6 ffff88082c7d6aa0 RU 0.0 0 0 [swapper]
> 0 0 7 ffff88102c506080 RU 0.0 0 0 [swapper]
> 0 0 8 ffff88082c016ae0 RU 0.0 0 0 [swapper]
> 0 0 9 ffff88102c506ae0 RU 0.0 0 0 [swapper]
> 0 0 10 ffff88082c05caa0 RU 0.0 0 0 [swapper]
> 0 0 11 ffff88102c507540 RU 0.0 0 0 [swapper]
> 0 0 12 ffff88082c09cae0 RU 0.0 0 0 [swapper]
.....
4926 1 5 ffff880828a38ae0 ?? 0.0 0 0 mingetty
4928 1 1 ffff88102a4e8040 ?? 0.0 0 0 mingetty
4930 1 19 ffff880827af4080 ?? 0.0 0 0 mingetty
4932 1 2 ffff88100f122040 ?? 0.0 0 0 mingetty
4934 1 18 ffff8810296ea080 ?? 0.0 0 0 mingetty
4936 1047 4 ffff880ff342d540 IN 0.0 11184 948 udevd
4937 1047 5 ffff88082a240080 IN 0.0 11184 948 udevd
5060 3772 2 ffff88082881d540 ?? 0.0 0 0 sshd
5078 1 1 ffff88100f060ae0 ?? 0.0 0 0 sshd
5079 1 1 ffff88082b882ae0 ?? 0.0 0 0 bash
如果我取出内核线程（无论如何，它们的 %MEM 都显示为零），我们可以看到最后几乎没有任何运行：
crash> ps -u
PID PPID CPU TASK ST %MEM VSZ RSS COMM
1 0 1 ffff88082c41b500 ?? 0.0 19348 348 init
1047 1 2 ffff881029524040 IN 0.0 11188 948 udevd
3171 1 3 ffff880826ccaaa0 IN 0.0 27636 240 auditd
3172 1 17 ffff881029d1b500 IN 0.0 27636 240 auditd
> 3772 1 0 ffff88102b257500 RU 0.0 64072 668 sshd
4800 1 0 ffff88100f061540 ?? 0.0 0 0 dsm_om_shrsvcd
4842 1 16 ffff88100f012ae0 ?? 0.0 0 0 cmcld
4854 1 17 ffff88082a241540 ?? 0.0 0 0 cmlogd
4855 1 3 ffff88082796cae0 ?? 0.0 0 0 cmfileassistd
4856 1 18 ffff88082809d500 ?? 0.0 0 0 cmnetd
4860 1 0 ffff88082705aae0 ?? 0.0 0 0 cmresourced
4924 1 9 ffff88102a4e8aa0 ?? 0.0 0 0 mingetty
4926 1 5 ffff880828a38ae0 ?? 0.0 0 0 mingetty
4928 1 1 ffff88102a4e8040 ?? 0.0 0 0 mingetty
4930 1 19 ffff880827af4080 ?? 0.0 0 0 mingetty
4932 1 2 ffff88100f122040 ?? 0.0 0 0 mingetty
4934 1 18 ffff8810296ea080 ?? 0.0 0 0 mingetty
4936 1047 4 ffff880ff342d540 IN 0.0 11184 948 udevd
4937 1047 5 ffff88082a240080 IN 0.0 11184 948 udevd
5060 3772 2 ffff88082881d540 ?? 0.0 0 0 sshd
5078 1 1 ffff88100f060ae0 ?? 0.0 0 0 sshd
5079 1 1 ffff88082b882ae0 ?? 0.0 0 0 bash
5257 1 1 ffff8808279e6aa0 ?? 0.0 0 0 jnx_mlnxsnmp_da
更新：
包括一些 Soham 建议的更多输出。不幸的是，我无法从中得出任何进一步的结论。我能做的最好的事情就是怀疑内核中存在内存泄漏，因为用户空间进程几乎全部死了。
crash> ps -G | tail -n +2 | cut -b2- | gawk '{mem += $8} END {print "total " mem/1048576 "GB"}'
total 0.00391006GB
请注意，此时几乎所有用户空间进程都处于停止状态，因此报告的使用率较低是可以预料的。
内存不足消息：
正如我上面提到的，有 39 条“内存不足：”消息，它们如下：
crash> log -m | grep Out
<3>[ 223.556616] Out of memory: Kill process 3189 (portreserve) score 1 or sacrifice child
<3>[ 223.787234] Out of memory: Kill process 3196 (rsyslogd) score 1 or sacrifice child
<3>[ 224.237119] Out of memory: Kill process 3728 (dbus-daemon) score 1 or sacrifice child
<3>[ 228.771770] Out of memory: Kill process 3758 (snmpd) score 1 or sacrifice child
<3>[ 229.033466] Out of memory: Kill process 3782 (xinetd) score 1 or sacrifice child
<3>[ 229.257710] Out of memory: Kill process 3782 (xinetd) score 1 or sacrifice child
<3>[ 229.484321] Out of memory: Kill process 3782 (xinetd) score 1 or sacrifice child
<3>[ 229.711169] Out of memory: Kill process 3782 (xinetd) score 1 or sacrifice child
<3>[ 229.934955] Out of memory: Kill process 3801 (cmproxyd) score 1 or sacrifice child
<3>[ 230.159542] Out of memory: Kill process 3812 (ntpd) score 1 or sacrifice child
<3>[ 230.382083] Out of memory: Kill process 3953 (master) score 1 or sacrifice child
<3>[ 230.606613] Out of memory: Kill process 3953 (master) score 1 or sacrifice child
<3>[ 230.829515] Out of memory: Kill process 3953 (master) score 1 or sacrifice child
<3>[ 230.832105] Out of memory: Kill process 3961 (crond) score 1 or sacrifice child
<3>[ 236.749746] Out of memory: Kill process 3974 (atd) score 1 or sacrifice child
<3>[ 236.969421] Out of memory: Kill process 4272 (dsm_sa_datamgrd) score 1 or sacrifice child
<3>[ 237.192102] Out of memory: Kill process 4492 (dsm_sa_datamgrd) score 1 or sacrifice child
<3>[ 237.746301] Out of memory: Kill process 4552 (dsm_sa_eventmgr) score 1 or sacrifice child
<3>[ 237.968308] Out of memory: Kill process 4613 (dsm_sa_snmpd) score 1 or sacrifice child
<3>[ 238.190550] Out of memory: Kill process 4614 (dsm_sa_snmpd) score 1 or sacrifice child
<3>[ 238.644020] Out of memory: Kill process 4643 (dsm_om_connsvcd) score 1 or sacrifice child
<3>[ 238.865658] Out of memory: Kill process 4643 (dsm_om_connsvcd) score 1 or sacrifice child
<3>[ 251.285450] Out of memory: Kill process 4643 (dsm_om_connsvcd) score 1 or sacrifice child
<3>[ 251.506601] Out of memory: Kill process 4800 (dsm_om_shrsvcd) score 1 or sacrifice child
<3>[ 251.727570] Out of memory: Kill process 4842 (cmcld) score 1 or sacrifice child
<3>[ 251.947085] Out of memory: Kill process 4842 (cmcld) score 1 or sacrifice child
<3>[ 252.167096] Out of memory: Kill process 4854 (cmlogd) score 1 or sacrifice child
<3>[ 252.384090] Out of memory: Kill process 4855 (cmfileassistd) score 1 or sacrifice child
<3>[ 252.603324] Out of memory: Kill process 4924 (mingetty) score 1 or sacrifice child
<3>[ 252.820757] Out of memory: Kill process 4926 (mingetty) score 1 or sacrifice child
<3>[ 253.037558] Out of memory: Kill process 4928 (mingetty) score 1 or sacrifice child
<3>[ 253.254908] Out of memory: Kill process 4930 (mingetty) score 1 or sacrifice child
<3>[ 253.257391] Out of memory: Kill process 4932 (mingetty) score 1 or sacrifice child
<3>[ 253.259357] Out of memory: Kill process 4934 (mingetty) score 1 or sacrifice child
<3>[ 253.261353] Out of memory: Kill process 5060 (sshd) score 1 or sacrifice child
<3>[ 253.263365] Out of memory: Kill process 5060 (sshd) score 1 or sacrifice child
<3>[ 253.264392] Out of memory: Kill process 5079 (bash) score 1 or sacrifice child
<3>[ 253.266352] Out of memory: Kill process 5257 (jnx_mlnxsnmp_da) score 1 or sacrifice child
<0>[ 253.529344] Kernel panic - not syncing: Out of memory and no killable processes...
系统输出：
crash> sys
KERNEL: /usr/lib/debug/lib/modules/2.6.32-279.5.2.el6.x86_64/vmlinux
DUMPFILE: pcdata03.vmcore.flat [PARTIAL DUMP]
CPUS: 32
DATE: Wed Feb 6 02:11:52 2013
UPTIME: 00:04:12
LOAD AVERAGE: 3.03, 0.95, 0.34
TASKS: 578
NODENAME: ....
RELEASE: 2.6.32-279.5.2.el6.x86_64
VERSION: #1 SMP Fri Aug 24 01:07:11 UTC 2012
MACHINE: x86_64 (2700 Mhz)
MEMORY: 64 GB
PANIC: "[ 253.529344] Kernel panic - not syncing: Out of memory and no killable processes..."
公里-z
crash> kmem -z
NODE: 0 ZONE: 0 ADDR: ffff88000000a0c0 NAME: "DMA"
SIZE: 4095 PRESENT: 3839 MIN/LOW/HIGH: 5/6/7
VM_STAT:
NR_FREE_PAGES: 3936
NR_INACTIVE_ANON: 0
NR_ACTIVE_ANON: 0
NR_INACTIVE_FILE: 0
NR_ACTIVE_FILE: 0
NR_UNEVICTABLE: 0
NR_MLOCK: 0
NR_ANON_PAGES: 0
NR_FILE_MAPPED: 0
NR_FILE_PAGES: 0
NR_FILE_DIRTY: 0
NR_WRITEBACK: 0
NR_SLAB_RECLAIMABLE: 0
NR_SLAB_UNRECLAIMABLE: 0
NR_PAGETABLE: 0
NR_KERNEL_STACK: 0
NR_UNSTABLE_NFS: 0
NR_BOUNCE: 0
NR_VMSCAN_WRITE: 0
NR_VMSCAN_IMMEDIATE: 0
NR_WRITEBACK_TEMP: 0
NR_ISOLATED_ANON: 0
NR_ISOLATED_FILE: 0
NR_SHMEM: 0
NUMA_HIT: 0
NUMA_MISS: 0
NUMA_FOREIGN: 0
NUMA_INTERLEAVE_HIT: 0
NUMA_LOCAL: 0
NUMA_OTHER: 0
NR_ANON_TRANSPARENT_HUGEPAGES: 0
NODE: 0 ZONE: 1 ADDR: ffff880000012780 NAME: "DMA32"
SIZE: 1044480 PRESENT: 756520 MIN/LOW/HIGH: 1030/1287/1545
VM_STAT:
NR_FREE_PAGES: 30117
NR_INACTIVE_ANON: 0
NR_ACTIVE_ANON: 0
NR_INACTIVE_FILE: 1
NR_ACTIVE_FILE: 0
NR_UNEVICTABLE: 0
NR_MLOCK: 0
NR_ANON_PAGES: 0
NR_FILE_MAPPED: 0
NR_FILE_PAGES: 1
NR_FILE_DIRTY: 0
NR_WRITEBACK: 0
NR_SLAB_RECLAIMABLE: 4
NR_SLAB_UNRECLAIMABLE: 4150
NR_PAGETABLE: 0
NR_KERNEL_STACK: 0
NR_UNSTABLE_NFS: 0
NR_BOUNCE: 0
NR_VMSCAN_WRITE: 0
NR_VMSCAN_IMMEDIATE: 0
NR_WRITEBACK_TEMP: 0
NR_ISOLATED_ANON: 0
NR_ISOLATED_FILE: 0
NR_SHMEM: 0
NUMA_HIT: 575606
NUMA_MISS: 3
NUMA_FOREIGN: 0
NUMA_INTERLEAVE_HIT: 0
NUMA_LOCAL: 575598
NUMA_OTHER: 11
NR_ANON_TRANSPARENT_HUGEPAGES: 0
NODE: 0 ZONE: 2 ADDR: ffff88000001ae40 NAME: "Normal"
SIZE: 7602176 PRESENT: 7498240 MIN/LOW/HIGH: 10217/12771/15325
VM_STAT:
NR_FREE_PAGES: 10443
NR_INACTIVE_ANON: 134
NR_ACTIVE_ANON: 197
NR_INACTIVE_FILE: -47
NR_ACTIVE_FILE: 42
NR_UNEVICTABLE: 0
NR_MLOCK: 0
NR_ANON_PAGES: 219
NR_FILE_MAPPED: 115
NR_FILE_PAGES: 45
NR_FILE_DIRTY: 0
NR_WRITEBACK: 0
NR_SLAB_RECLAIMABLE: 908
NR_SLAB_UNRECLAIMABLE: 18771
NR_PAGETABLE: 91
NR_KERNEL_STACK: 556
NR_UNSTABLE_NFS: 0
NR_BOUNCE: 0
NR_VMSCAN_WRITE: 0
NR_VMSCAN_IMMEDIATE: 0
NR_WRITEBACK_TEMP: 0
NR_ISOLATED_ANON: 0
NR_ISOLATED_FILE: 0
NR_SHMEM: 34
NUMA_HIT: 8243991
NUMA_MISS: 648
NUMA_FOREIGN: 4593726
NUMA_INTERLEAVE_HIT: 20066
NUMA_LOCAL: 8243829
NUMA_OTHER: 810
NR_ANON_TRANSPARENT_HUGEPAGES: 0
NODE: 0 ZONE: 3 ADDR: ffff880000023500 NAME: "Movable"
[unpopulated]
NODE: 1 ZONE: 0 ADDR: ffff880840000040 NAME: "DMA"
[unpopulated]
NODE: 1 ZONE: 1 ADDR: ffff880840008700 NAME: "DMA32"
[unpopulated]
NODE: 1 ZONE: 2 ADDR: ffff880840010dc0 NAME: "Normal"
SIZE: 8388608 PRESENT: 8273920 MIN/LOW/HIGH: 11274/14092/16911
VM_STAT:
NR_FREE_PAGES: 10114
NR_INACTIVE_ANON: 417
NR_ACTIVE_ANON: 83
NR_INACTIVE_FILE: 47
NR_ACTIVE_FILE: 32
NR_UNEVICTABLE: 0
NR_MLOCK: 0
NR_ANON_PAGES: 436
NR_FILE_MAPPED: 22
NR_FILE_PAGES: 154
NR_FILE_DIRTY: 0
NR_WRITEBACK: 0
NR_SLAB_RECLAIMABLE: 863
NR_SLAB_UNRECLAIMABLE: 21939
NR_PAGETABLE: 134
NR_KERNEL_STACK: 27
NR_UNSTABLE_NFS: 0
NR_BOUNCE: 0
NR_VMSCAN_WRITE: 3
NR_VMSCAN_IMMEDIATE: 5
NR_WRITEBACK_TEMP: 0
NR_ISOLATED_ANON: 0
NR_ISOLATED_FILE: 23
NR_SHMEM: 20
NUMA_HIT: 4332488
NUMA_MISS: 4593726
NUMA_FOREIGN: 665
NUMA_INTERLEAVE_HIT: 20007
NUMA_LOCAL: 4309300
NUMA_OTHER: 4616914
NR_ANON_TRANSPARENT_HUGEPAGES: 0
NODE: 1 ZONE: 3 ADDR: ffff880840019480 NAME: "Movable"
[unpopulated]
公里姆-f
crash> kmem -f
NODE
0
ZONE NAME SIZE FREE MEM_MAP START_PADDR START_MAPNR
0 DMA 4095 3936 ffffea0000000038 1000 0
AREA SIZE FREE_AREA_STRUCT BLOCKS PAGES
0 4k ffff880000012128 2 2
0 4k ffff880000012138 0 0
0 4k ffff880000012148 0 0
0 4k ffff880000012158 0 0
0 4k ffff880000012168 0 0
1 8k ffff880000012180 1 2
1 8k ffff880000012190 0 0
1 8k ffff8800000121a0 0 0
1 8k ffff8800000121b0 0 0
1 8k ffff8800000121c0 0 0
2 16k ffff8800000121d8 1 4
2 16k ffff8800000121e8 0 0
2 16k ffff8800000121f8 0 0
2 16k ffff880000012208 0 0
2 16k ffff880000012218 0 0
3 32k ffff880000012230 1 8
3 32k ffff880000012240 0 0
3 32k ffff880000012250 0 0
3 32k ffff880000012260 0 0
3 32k ffff880000012270 0 0
4 64k ffff880000012288 1 16
4 64k ffff880000012298 0 0
4 64k ffff8800000122a8 0 0
4 64k ffff8800000122b8 0 0
4 64k ffff8800000122c8 0 0
5 128k ffff8800000122e0 0 0
5 128k ffff8800000122f0 0 0
5 128k ffff880000012300 0 0
5 128k ffff880000012310 0 0
5 128k ffff880000012320 0 0
6 256k ffff880000012338 1 64
6 256k ffff880000012348 0 0
6 256k ffff880000012358 0 0
6 256k ffff880000012368 0 0
6 256k ffff880000012378 0 0
7 512k ffff880000012390 0 0
7 512k ffff8800000123a0 0 0
7 512k ffff8800000123b0 0 0
7 512k ffff8800000123c0 0 0
7 512k ffff8800000123d0 0 0
8 1024k ffff8800000123e8 1 256
8 1024k ffff8800000123f8 0 0
8 1024k ffff880000012408 0 0
8 1024k ffff880000012418 0 0
8 1024k ffff880000012428 0 0
9 2048k ffff880000012440 0 0
9 2048k ffff880000012450 0 0
9 2048k ffff880000012460 0 0
9 2048k ffff880000012470 1 512
9 2048k ffff880000012480 0 0
10 4096k ffff880000012498 0 0
10 4096k ffff8800000124a8 0 0
10 4096k ffff8800000124b8 3 3072
10 4096k ffff8800000124c8 0 0
10 4096k ffff8800000124d8 0 0
ZONE NAME SIZE FREE MEM_MAP START_PADDR START_MAPNR
1 DMA32 1044480 30117 ffffea0000038000 1000000 4095
AREA SIZE FREE_AREA_STRUCT BLOCKS PAGES
0 4k ffff88000001a7e8 24 24
0 4k ffff88000001a7f8 4 4
0 4k ffff88000001a808 13 13
0 4k ffff88000001a818 0 0
0 4k ffff88000001a828 0 0
1 8k ffff88000001a840 2 4
1 8k ffff88000001a850 2 4
1 8k ffff88000001a860 4 8
1 8k ffff88000001a870 0 0
1 8k ffff88000001a880 0 0
2 16k ffff88000001a898 0 0
2 16k ffff88000001a8a8 3 12
2 16k ffff88000001a8b8 4 16
2 16k ffff88000001a8c8 0 0
2 16k ffff88000001a8d8 0 0
3 32k ffff88000001a8f0 0 0
3 32k ffff88000001a900 3 24
3 32k ffff88000001a910 3 24
3 32k ffff88000001a920 0 0
3 32k ffff88000001a930 0 0
4 64k ffff88000001a948 1 16
4 64k ffff88000001a958 3 48
4 64k ffff88000001a968 6 96
4 64k ffff88000001a978 0 0
4 64k ffff88000001a988 0 0
5 128k ffff88000001a9a0 0 0
5 128k ffff88000001a9b0 3 96
5 128k ffff88000001a9c0 7 224
5 128k ffff88000001a9d0 0 0
5 128k ffff88000001a9e0 0 0
6 256k ffff88000001a9f8 0 0
6 256k ffff88000001aa08 1 64
6 256k ffff88000001aa18 6 384
6 256k ffff88000001aa28 0 0
6 256k ffff88000001aa38 0 0
7 512k ffff88000001aa50 1 128
7 512k ffff88000001aa60 0 0
7 512k ffff88000001aa70 8 1024
7 512k ffff88000001aa80 0 0
7 512k ffff88000001aa90 0 0
8 1024k ffff88000001aaa8 1 256
8 1024k ffff88000001aab8 1 256
8 1024k ffff88000001aac8 5 1280
8 1024k ffff88000001aad8 0 0
8 1024k ffff88000001aae8 0 0
9 2048k ffff88000001ab00 0 0
9 2048k ffff88000001ab10 1 512
9 2048k ffff88000001ab20 3 1536
9 2048k ffff88000001ab30 1 512
9 2048k ffff88000001ab40 0 0
10 4096k ffff88000001ab58 0 0
10 4096k ffff88000001ab68 0 0
10 4096k ffff88000001ab78 22 22528
10 4096k ffff88000001ab88 1 1024
10 4096k ffff88000001ab98 0 0
ZONE NAME SIZE FREE MEM_MAP START_PADDR START_MAPNR
2 Normal 7602176 10443 ffffea0003800000 100000000 1048575
AREA SIZE FREE_AREA_STRUCT BLOCKS PAGES
0 4k ffff880000022ea8 365 365
0 4k ffff880000022eb8 274 274
0 4k ffff880000022ec8 274 274
0 4k ffff880000022ed8 0 0
0 4k ffff880000022ee8 0 0
1 8k ffff880000022f00 99 198
1 8k ffff880000022f10 94 188
1 8k ffff880000022f20 360 720
1 8k ffff880000022f30 0 0
1 8k ffff880000022f40 0 0
2 16k ffff880000022f58 30 120
2 16k ffff880000022f68 41 164
2 16k ffff880000022f78 204 816
2 16k ffff880000022f88 0 0
2 16k ffff880000022f98 0 0
3 32k ffff880000022fb0 9 72
3 32k ffff880000022fc0 19 152
3 32k ffff880000022fd0 138 1104
3 32k ffff880000022fe0 0 0
3 32k ffff880000022ff0 0 0
4 64k ffff880000023008 7 112
4 64k ffff880000023018 4 64
4 64k ffff880000023028 77 1232
4 64k ffff880000023038 0 0
4 64k ffff880000023048 0 0
5 128k ffff880000023060 3 96
5 128k ffff880000023070 3 96
5 128k ffff880000023080 43 1376
5 128k ffff880000023090 0 0
5 128k ffff8800000230a0 0 0
6 256k ffff8800000230b8 0 0
6 256k ffff8800000230c8 0 0
6 256k ffff8800000230d8 13 832
6 256k ffff8800000230e8 0 0
6 256k ffff8800000230f8 0 0
7 512k ffff880000023110 0 0
7 512k ffff880000023120 0 0
7 512k ffff880000023130 5 640
7 512k ffff880000023140 0 0
7 512k ffff880000023150 0 0
8 1024k ffff880000023168 0 0
8 1024k ffff880000023178 0 0
8 1024k ffff880000023188 0 0
8 1024k ffff880000023198 0 0
8 1024k ffff8800000231a8 0 0
9 2048k ffff8800000231c0 0 0
9 2048k ffff8800000231d0 0 0
9 2048k ffff8800000231e0 1 512
9 2048k ffff8800000231f0 0 0
9 2048k ffff880000023200 0 0
10 4096k ffff880000023218 0 0
10 4096k ffff880000023228 0 0
10 4096k ffff880000023238 0 0
10 4096k ffff880000023248 1 1024
10 4096k ffff880000023258 0 0
ZONE NAME SIZE FREE MEM_MAP START_PADDR START_MAPNR
3 Movable 0 0 0 0 0
--------------------------------------------------------------------------
NODE
1
ZONE NAME SIZE FREE MEM_MAP START_PADDR START_MAPNR
0 DMA 0 0 0 0 0
ZONE NAME SIZE FREE MEM_MAP START_PADDR START_MAPNR
1 DMA32 0 0 0 0 0
ZONE NAME SIZE FREE MEM_MAP START_PADDR START_MAPNR
2 Normal 8388608 10114 ffffea001ce00000 840000000 0
AREA SIZE FREE_AREA_STRUCT BLOCKS PAGES
0 4k ffff880840018e28 405 405
0 4k ffff880840018e38 162 162
0 4k ffff880840018e48 317 317
0 4k ffff880840018e58 0 0
0 4k ffff880840018e68 0 0
1 8k ffff880840018e80 106 212
1 8k ffff880840018e90 70 140
1 8k ffff880840018ea0 269 538
1 8k ffff880840018eb0 0 0
1 8k ffff880840018ec0 0 0
2 16k ffff880840018ed8 24 96
2 16k ffff880840018ee8 18 72
2 16k ffff880840018ef8 207 828
2 16k ffff880840018f08 0 0
2 16k ffff880840018f18 0 0
3 32k ffff880840018f30 20 160
3 32k ffff880840018f40 4 32
3 32k ffff880840018f50 148 1184
3 32k ffff880840018f60 0 0
3 32k ffff880840018f70 0 0
4 64k ffff880840018f88 17 272
4 64k ffff880840018f98 2 32
4 64k ffff880840018fa8 95 1520
4 64k ffff880840018fb8 0 0
4 64k ffff880840018fc8 0 0
5 128k ffff880840018fe0 4 128
5 128k ffff880840018ff0 1 32
5 128k ffff880840019000 37 1184
5 128k ffff880840019010 0 0
5 128k ffff880840019020 0 0
6 256k ffff880840019038 0 0
6 256k ffff880840019048 0 0
6 256k ffff880840019058 8 512
6 256k ffff880840019068 0 0
6 256k ffff880840019078 0 0
7 512k ffff880840019090 0 0
7 512k ffff8808400190a0 0 0
7 512k ffff8808400190b0 1 128
7 512k ffff8808400190c0 0 0
7 512k ffff8808400190d0 0 0
8 1024k ffff8808400190e8 0 0
8 1024k ffff8808400190f8 0 0
8 1024k ffff880840019108 1 256
8 1024k ffff880840019118 0 0
8 1024k ffff880840019128 0 0
9 2048k ffff880840019140 0 0
9 2048k ffff880840019150 0 0
9 2048k ffff880840019160 1 512
9 2048k ffff880840019170 1 512
9 2048k ffff880840019180 0 0
10 4096k ffff880840019198 0 0
10 4096k ffff8808400191a8 0 0
10 4096k ffff8808400191b8 0 0
10 4096k ffff8808400191c8 1 1024
10 4096k ffff8808400191d8 0 0
ZONE NAME SIZE FREE MEM_MAP START_PADDR START_MAPNR
3 Movable 0 0 0 0 0
nr_free_pages: 54610 (found 54742)
进行一些练习foreach bt
crash> foreach bt | awk '$1 == "#0" { $2 = ""; print }' | sort | uniq -c
31 #0 crash_nmi_callback at ffffffff81029df6
1 #0 machine_kexec at ffffffff8103281b
546 #0 schedule at ffffffff814fda62
确实，它们要么崩溃了，要么正在等待内存（或者我没有正确读取）。
答案1
检查物理内存（驻留集大小）最大的 20 个消耗者。
crash> ps -G | sed 's/>//g' | sort -k 8,8 -n | awk '$8 ~ /[0-9]/{ $8 = $8/1024" MB"; print }' | tail -20
检查大页面的数量。
crash> p -d nr_huge_pages
更新：
A) 从以下内核版本捕获崩溃转储。
$ crash --osrelease vmcore.flat
2.6.32-279.5.2.el6.x86_64
B) 让我们从 kernel-debug-debuginfo 包中提取 vmlinux 文件。
$ rpm2cpio kernel-debug-debuginfo-2.6.32-279.5.2.el6.x86_64.rpm | \
cpio -idv ./usr/lib/debug/lib/modules/*/vmlinux
C）使用崩溃实用程序打开 vmcore 文件。
$ bunzip2 vmcore.flat.bz2
$ crash vmcore.flat ./usr/lib/debug/lib/modules/2.6.32-279.5.2.el6.x86_64/vmlinux
D)系统信息。
crash> sys
KERNEL: ./usr/lib/debug/lib/modules/2.6.32-279.5.2.el6.x86_64/vmlinux
DUMPFILE: vmcore.flat [PARTIAL DUMP]
CPUS: 32
DATE: Tue Feb 5 12:11:52 2013
UPTIME: 00:04:12
LOAD AVERAGE: 3.03, 0.95, 0.34
TASKS: 578
NODENAME: ...
RELEASE: 2.6.32-279.5.2.el6.x86_64
VERSION: #1 SMP Fri Aug 24 01:07:11 UTC 2012
MACHINE: x86_64 (2700 Mhz)
MEMORY: 64 GB
PANIC: "[ 253.529344] Kernel panic - not syncing: Out of memory and no killable processes..."
a) 由于内存不足而发生恐慌，但系统上已禁用“panic_on_oom”参数。
crash> p -d sysctl_panic_on_oom
sysctl_panic_on_oom = $6 = 0
此参数启用或禁用内存不足时崩溃功能。如果将此参数设置为 0，内核将杀死一些恶意进程，称为 oom_killer。通常，oom_killer 可以杀死恶意进程，系统将幸存下来。如果将此参数设置为 1，当发生内存不足时，内核将崩溃。
b) 那么，我们如何捕获oom事件时的vmcore呢？
好吧，让我们检查一下 mm/oom_kill.c 源代码。它说如果系统上没有剩余可杀死的东西，那么就直接挂起或崩溃。
++++++
499 /* Found nothing?!?! Either we hang forever, or we panic. */
500 if (!p) {
501 read_unlock(&tasklist_lock);
502 cpuset_unlock();
503 panic("Out of memory and no killable processes...\n"); <<<------
504 }
505
++++++
因此我们进入了恐慌状态，并且由于此系统上启用了 kdump 服务，因此 vmcore 被捕获。
E）检查内核环形缓冲区，
crash> log
[..]
[ 253.351427] Node 0 DMA free:15744kB min:20kB low:24kB high:28kB active_anon:0kB inactive_anon:0kB active_file:0kB inactive_file:0kB unevictable:0kB isolated(anon):0kB isolated(file):0kB present:15356kB mlocked:0kB dirty:0kB writeback:0kB mapped:0kB shmem:0kB slab_reclaimable:0kB slab_unreclaimable:0kB kernel_stack:0kB pagetables:0kB unstable:0kB bounce:0kB writeback_tmp:0kB pages_scanned:0 all_unreclaimable? yes
[ 253.352234] lowmem_reserve[]: 0 2955 32245 32245
[ 253.352812] Node 0 DMA32 free:120436kB min:4120kB low:5148kB high:6180kB active_anon:0kB inactive_anon:0kB active_file:0kB inactive_file:32kB unevictable:0kB isolated(anon):0kB isolated(file):0kB present:3026080kB mlocked:0kB dirty:0kB writeback:0kB mapped:0kB shmem:0kB slab_reclaimable:20kB slab_unreclaimable:16600kB kernel_stack:0kB pagetables:0kB unstable:0kB bounce:0kB writeback_tmp:0kB pages_scanned:1 all_unreclaimable? no
[ 253.353637] lowmem_reserve[]: 0 0 29290 29290
[ 253.354216] Node 0 Normal free:40580kB min:40868kB low:51084kB high:61300kB active_anon:956kB inactive_anon:536kB active_file:260kB inactive_file:0kB unevictable:0kB isolated(anon):0kB isolated(file):0kB present:29992960kB mlocked:0kB dirty:0kB writeback:0kB mapped:460kB shmem:136kB slab_reclaimable:3640kB slab_unreclaimable:75128kB kernel_stack:4448kB pagetables:428kB unstable:0kB bounce:0kB writeback_tmp:0kB pages_scanned:0 all_unreclaimable? no
[ 253.355047] lowmem_reserve[]: 0 0 0 0
[ 253.355624] Node 1 Normal free:39896kB min:45096kB low:56368kB high:67644kB active_anon:412kB inactive_anon:1668kB active_file:288kB inactive_file:0kB unevictable:0kB isolated(anon):0kB isolated(file):220kB present:33095680kB mlocked:0kB dirty:0kB writeback:0kB mapped:92kB shmem:80kB slab_reclaimable:3496kB slab_unreclaimable:87864kB kernel_stack:216kB pagetables:564kB unstable:0kB bounce:0kB writeback_tmp:0kB pages_scanned:0 all_unreclaimable? no
[ 253.356457] lowmem_reserve[]: 0 0 0 0
[ 253.357034] Node 0 DMA: 2*4kB 1*8kB 1*16kB 1*32kB 1*64kB 0*128kB 1*256kB 0*512kB 1*1024kB 1*2048kB 3*4096kB = 15744kB
[ 253.358351] Node 0 DMA32: 41*4kB 8*8kB 7*16kB 6*32kB 10*64kB 10*128kB 7*256kB 9*512kB 7*1024kB 5*2048kB 23*4096kB = 120468kB
[ 253.359674] Node 0 Normal: 718*4kB 558*8kB 278*16kB 169*32kB 88*64kB 47*128kB 13*256kB 5*512kB 0*1024kB 1*2048kB 1*4096kB = 40872kB
[ 253.360995] Node 1 Normal: 876*4kB 447*8kB 249*16kB 174*32kB 116*64kB 40*128kB 8*256kB 1*512kB 1*1024kB 2*2048kB 1*4096kB = 40952kB
[ 253.362319] 154 total pagecache pages
[ 253.362502] 0 pages in swap cache
[ 253.362684] Swap cache stats: add 0, delete 0, find 0/0
[ 253.362869] Free swap = 0kB
[ 253.363050] Total swap = 0kB
[ 253.526814] 16777215 pages RAM
[ 253.526999] 294628 pages reserved
[ 253.527190] 114911 pages shared
[ 253.527372] 16392561 pages non-shared
[..]
F）让我们检查系统崩溃时的内存状态。
crash> kmem -i
PAGES TOTAL PERCENTAGE
TOTAL MEM 16482587 62.9 GB ---- -------------------------------+
FREE 54610 213.3 MB 0% of TOTAL MEM |
USED 16427977 62.7 GB 99% of TOTAL MEM |
SHARED 4683 18.3 MB 0% of TOTAL MEM |
BUFFERS 118 472 KB 0% of TOTAL MEM |
CACHED 82 328 KB 0% of TOTAL MEM |
SLAB 46635 182.2 MB 0% of TOTAL MEM |
|
TOTAL SWAP 0 0 ---- ----------------------+ |
SWAP USED 0 0 100% of TOTAL SWAP | |
SWAP FREE 0 0 0% of TOTAL SWAP | |
| |
| |
crash> p -d totalram_pages | |
totalram_pages = $5 = 16482587 | |
| |
crash> !echo "scale=5;(16482587*4096)/2^30"|bc -q | |
62.87607 <<<-----[ Total physical memory is 62.9 GB ] <<<--|--------+
|
crash> p -d total_swap_pages |
total_swap_pages = $6 = 0 <<<------[ No Swap on the system ] <<<-----------+
- 我们的物理内存总计约为 63GiB。
- 系统上未创建交换分区或文件，因此我们在此服务器上没有交换。
- 用于缓存的内存非常少，只有 328KB，用于缓冲区的内存为 472KB。
- slab 中使用的内存也很少，只有 182.2 MB。
G）分配给进程的总内存为 0.00391006GiB。
crash> ps -G | tail -n +2 | cut -b2- | gawk '{mem += $8} END {print "total " mem/1048576 "GB"}'
total 0.00391006GB
H) 应用程序进程未使用系统内存。
crash> ps -G | sed 's/>//g' | sort -k 8,8 -n | awk '$8 ~ /[0-9]/{ $8 = $8/1024" MB"; print }' | tail -20
965 2 21 ffff8808292f1500 IN 0.0 0 0 MB [ext4-dio-unwrit]
966 2 22 ffff8808292d4080 IN 0.0 0 0 MB [ext4-dio-unwrit]
967 2 23 ffff8808292ce040 IN 0.0 0 0 MB [ext4-dio-unwrit]
968 2 24 ffff8808299b5540 IN 0.0 0 0 MB [ext4-dio-unwrit]
969 2 25 ffff880829aa6040 IN 0.0 0 0 MB [ext4-dio-unwrit]
970 2 26 ffff880827367500 IN 0.0 0 0 MB [ext4-dio-unwrit]
971 2 27 ffff880827366aa0 IN 0.0 0 0 MB [ext4-dio-unwrit]
972 2 28 ffff880827366040 IN 0.0 0 0 MB [ext4-dio-unwrit]
97 2 23 ffff88082c1ac080 IN 0.0 0 0 MB [ksoftirqd/23]
973 2 29 ffff880827371540 IN 0.0 0 0 MB [ext4-dio-unwrit]
974 2 30 ffff880827370ae0 IN 0.0 0 0 MB [ext4-dio-unwrit]
975 2 31 ffff880827370080 IN 0.0 0 0 MB [ext4-dio-unwrit]
98 2 23 ffff88082c1bb500 IN 0.0 0 0 MB [watchdog/23]
99 2 24 ffff88082c1baaa0 IN 0.0 0 0 MB [migration/24]
3171 1 3 ffff880826ccaaa0 IN 0.0 27636 0.234375 MB auditd
1 0 1 ffff88082c41b500 UN 0.0 19348 0.339844 MB init
3772 1 0 ffff88102b257500 RU 0.0 64072 0.652344 MB sshd
1047 1 2 ffff881029524040 IN 0.0 11188 0.925781 MB udevd
4936 1047 4 ffff880ff342d540 IN 0.0 11184 0.925781 MB udevd
4937 1047 5 ffff88082a240080 IN 0.0 11184 0.925781 MB udevd
I）让我们验证系统上的内存调整参数。
crash> p -d sysctl_overcommit_memory
sysctl_overcommit_memory = $7 = 0
此值包含一个启用内存过量使用的标志。当此标志为 0 时，内核会在用户空间请求更多内存时尝试估计剩余的可用内存量。
crash> p -d sysctl_overcommit_ratio
sysctl_overcommit_ratio = $8 = 50
当 overcommit_memory 设置为 2 时，提交的地址空间不允许超过交换加上该百分比的物理 RAM。
crash> p -d zone_reclaim_mode
zone_reclaim_mode = $4 = 0
Zone_reclaim_mode 允许某人在区域内存不足时设置更积极或更消极的方法来回收内存。如果将其设置为零，则不会发生区域回收。
crash> p -d min_free_kbytes
min_free_kbytes = $3 = 90112 <<<--------[ 88 MB ]
整个系统中保持空闲的最小千字节数。此值用于计算每个低内存区域的水位线值，然后为其分配与其大小成比例的保留空闲页面数。设置此参数时，过低和过高的值都可能造成损害。
换句话说，设置得min_free_kbytes太低会阻止系统回收内存。这可能会导致系统挂起并导致多个进程 OOM 终止。但是，将此参数设置为过高的值（系统总内存的 5-10%）会导致系统立即内存不足。Linux 旨在使用所有可用 RAM 来缓存文件系统数据。设置较高的 min_free_kbytes 值会导致系统花费太多时间来回收内存。
上述参数的值看起来没问题，那么我的记忆在哪里呢？
假设：
- 主要罪魁祸首不在用户空间。根据我的经验，无法解释的内存是由 Mellanox 和 DRBD 模块引起的，但我不确定您的情况。
- 由于为了减小 vmcore 文件的大小，大多数页面都会从 vmcore 文件中丢弃（ core_collector makedumpfile -d 31 -c ）。因此，我无法检查大页面大小。
答案2
您能运行这个命令吗？
ps -G | tail -n +2 | cut -b2- | gawk '{mem += $8} END {Print "total " mem/1048576 "GB"}'
此外，kmem -z 和 kmem -f 可能会有帮助。
但是，请注意整个交换空间已被消耗。
日志命令中肯定有一些 OOM 消息。你能将 OOM 消息粘贴到 pastebin 中吗？我也可以看到模式和竞争条件。
另外，系统输出将大有帮助。你知道，内存泄漏和内核升级几乎是同义词 ;)
编辑：自己尝试一下。 foreach bt
它将显示每个 PID 的跟踪。查找任何常见模式，可能是它们都在等待该schedule_at函数。这意味着某些东西正在等待内存分配。
现在，请注意显示 foreach bt 中每个 PID 的部分中 TASK 的值。
运行这个。
tasK_struct.tgid <TASK>
如果它们来自相同的 PID，那么您看到的进程就是线程化的。
我忘了如何检查过度提交的值，我会看看是否能找到答案。
答案3
我没有太多分析崩溃转储的经验，因此无法为您提供一些具体的建议，但这里有一些我经常收集和使用的链接。也许你会发现一些有用的东西：
答案4
您可能知道这一点，只是没有表明您做了什么，但是，有很多选择。
# ps aux
或者
# ps -edf
因为 root 将会吐出更详细的信息。
此页面上有大量有用的建议，可帮助您追踪内存问题：
http://www.linuxnix.com/2011/05/find-ram-utilization-user-linux.html
我会检查
# free
定期查看实际使用了多少内存。（或者更好的是，将其绘制成图表；graphite 或 munin 非常适合此用途）以便您可以直观地了解何时/如何使用内存。
64GB 的 RAM 相当多；主机用来做什么工作？