令人困惑的内存泄漏。什么在此系统上使用约10GB的内存？

运行约18小时后，该系统使用了约10GB的内存，导致在执行我们的常规任务时触发OOM杀手：

# free -h
             total       used       free     shared    buffers     cached
Mem:           14G       9.4G       5.3G       400K        27M        59M
-/+ buffers/cache:       9.3G       5.4G
Swap:           0B         0B         0B

# cat /proc/meminfo
MemTotal:       15400928 kB
MemFree:         5567028 kB
Buffers:           28464 kB
Cached:            60816 kB
SwapCached:            0 kB
Active:           321464 kB
Inactive:          59156 kB
Active(anon):     291464 kB
Inactive(anon):      316 kB
Active(file):      30000 kB
Inactive(file):    58840 kB
Unevictable:           0 kB
Mlocked:               0 kB
SwapTotal:             0 kB
SwapFree:              0 kB
Dirty:                40 kB
Writeback:             0 kB
AnonPages:        291380 kB
Mapped:            14356 kB
Shmem:               400 kB
Slab:             364596 kB
SReclaimable:      18856 kB
SUnreclaim:       345740 kB
KernelStack:        1832 kB
PageTables:         3720 kB
NFS_Unstable:          0 kB
Bounce:                0 kB
WritebackTmp:          0 kB
CommitLimit:     7700464 kB
Committed_AS:     313224 kB
VmallocTotal:   34359738367 kB
VmallocUsed:       35976 kB
VmallocChunk:   34359678732 kB
HardwareCorrupted:     0 kB
AnonHugePages:    231424 kB
HugePages_Total:       0
HugePages_Free:        0
HugePages_Rsvd:        0
HugePages_Surp:        0
Hugepagesize:       2048 kB
DirectMap4k:     9598976 kB
DirectMap2M:     6260736 kB

但是，进程似乎并没有使用大量的此内存：

# top -o %MEM -n 1
top - 15:07:00 up 18:28,  1 user,  load average: 0.00, 0.01, 0.05
Tasks: 155 total,   1 running, 154 sleeping,   0 stopped,   0 zombie
%Cpu(s): 23.7 us,  4.8 sy,  0.0 ni, 71.4 id,  0.0 wa,  0.0 hi,  0.1 si,  0.0 st
KiB Mem:  15400928 total,  9838560 used,  5562368 free,    29764 buffers
KiB Swap:        0 total,        0 used,        0 free.    62760 cached Mem

  PID USER      PR  NI    VIRT    RES    SHR S  %CPU %MEM     TIME+ COMMAND
 1333 root      20   0 5763204 274132   5352 S   0.0  1.8   7:00.19 java
 1466 newrelic  20   0  251484   4884   2056 S   0.0  0.0   0:56.41 nrsysmond
16804 root      20   0  105636   4212   3224 S   0.0  0.0   0:00.00 sshd
16876 root      20   0   21420   3908   1764 S   0.0  0.0   0:00.03 bash
16858 ubuntu    20   0   21456   3828   1684 S   0.0  0.0   0:00.05 bash
  770 root      20   0   10216   2868    576 S   0.0  0.0   0:00.02 dhclient
    1 root      20   0   33700   2216    624 S   0.0  0.0   0:35.50 init
16875 root      20   0   63664   2084   1612 S   0.0  0.0   0:00.00 sudo
16857 ubuntu    20   0  105636   1860    880 S   0.0  0.0   0:00.01 sshd
16920 root      20   0   23688   1528   1064 R   0.0  0.0   0:00.00 top
16803 postfix   20   0   27400   1492   1216 S   0.0  0.0   0:00.00 pickup
  976 root      20   0   43444   1100    748 S   0.0  0.0   0:00.00     systemd-logind
  572 root      20   0   51480   1048    308 S   0.0  0.0   0:00.53     systemd-udevd
 1840 ntp       20   0   31448   1044    448 S   0.0  0.0   0:02.94 ntpd
  990 syslog    20   0  255836    924     76 S   0.0  0.0   0:00.13 rsyslogd
 1167 root      20   0   61372    828    148 S   0.0  0.0   0:00.00 sshd
  945 message+  20   0   39212    788    416 S   0.0  0.0   0:00.12 dbus-daemon
 1323 root      20   0   20692    676      0 S   0.0  0.0   0:40.92 wrapper
 1230 root      20   0   19320    588    244 S   0.0  0.0   0:04.57 irqbalance
 1538 root      20   0   25336    500    188 S   0.0  0.0   0:00.18 master
  567 root      20   0   19604    480     96 S   0.0  0.0   0:00.34     upstart-udev-br
 1175 root      20   0   23648    404    156 S   0.0  0.0   0:00.08 cron
 1005 root      20   0   15272    348     88 S   0.0  0.0   0:00.08     upstart-file-br

临时和共享内存文件系统基本上是空的：

# df -h
Filesystem      Size  Used Avail Use% Mounted on
udev            7.4G   12K  7.4G   1% /dev
tmpfs           1.5G  384K  1.5G   1% /run
/dev/xvda1      9.8G  6.7G  2.7G  72% /
none            4.0K     0  4.0K   0% /sys/fs/cgroup
none            5.0M     0  5.0M   0% /run/lock
none            7.4G     0  7.4G   0% /run/shm
none            100M     0  100M   0% /run/user
/dev/xvda15     104M  4.7M   99M   5% /boot/efi
/dev/xvdb        64G  1.1G   60G   2% /mnt

smem 说它正在被内核使用：

# smem -tw
Area                           Used      Cache   Noncache
firmware/hardware                 0          0          0
kernel image                      0          0          0
kernel dynamic memory       9525544      92468    9433076
userspace memory             311064      15648     295416
free memory                 5564320    5564320          0
----------------------------------------------------------
                           15400928    5672436    9728492

但是slabtop没有帮助：

# slabtop -o -s c
 Active / Total Objects (% used)    : 2915263 / 2937006 (99.3%)
 Active / Total Slabs (% used)      : 60745 / 60745 (100.0%)
 Active / Total Caches (% used)     : 68 / 103 (66.0%)
 Active / Total Size (% used)       : 356086.71K / 360884.30K (98.7%)
 Minimum / Average / Maximum Object : 0.01K / 0.12K / 14.00K

  OBJS ACTIVE  USE OBJ SIZE  SLABS OBJ/SLAB CACHE SIZE NAME
2226784 2226784 100%    0.07K  39764       56    159056K Acpi-ParseExt
273408 272598  99%    0.25K   8544       32     68352K kmalloc-256
  8568   8560  99%    4.00K   1071        8     34272K kmalloc-4096
 52320  52320 100%    0.50K   1635       32     26160K kmalloc-512
  1988   1975  99%    8.00K    497        4     15904K kmalloc-8192
 58044  53370  91%    0.19K   2764       21     11056K kmalloc-192
150016 141356  94%    0.06K   2344       64      9376K kmalloc-64
  5016   3504  69%    0.96K    152       33      4864K ext4_inode_cache
  7280   6834  93%    0.57K    260       28      4160K inode_cache
 20265  20067  99%    0.19K    965       21      3860K dentry
  1760   1721  97%    2.00K    110       16      3520K kmalloc-2048
 19800  19800 100%    0.11K    550       36      2200K sysfs_dir_cache
  2112   1966  93%    1.00K     66       32      2112K kmalloc-1024
   305    260  85%    6.00K     61        5      1952K task_struct
 14616  14242  97%    0.09K    348       42      1392K kmalloc-96
  2125   2092  98%    0.63K     85       25      1360K proc_inode_cache
  2324   2324 100%    0.55K     83       28      1328K radix_tree_node
  9828   9828 100%    0.10K    252       39      1008K buffer_head
  1400   1400 100%    0.62K     56       25       896K sock_inode_cache
    54     39  72%   12.00K     27        2       864K nvidia_stack_cache
   975    975 100%    0.81K     25       39       800K task_xstate
   690    515  74%    1.06K     23       30       736K signal_cache

到目前为止，我能够解决此问题的唯一方法是重新启动。10GB的内存可以藏在哪里？

我正在运行一个具有32GB内存的盒子，其突出区别是DirectMap4k值；

DirectMap4k:      493076 kB
DirectMap2M:     7862272 kB
DirectMap1G:    27262976 kB

与你的

DirectMap4k:    11182080 kB
DirectMap2M:     4677632 kB

可能是一个起点。.Googling建议此值可能受主机向VPS分配的影响...您是否在虚拟服务器中运行此计算机？

可能是主机服务器没有足够的RAM，并且弄乱了的输出/proc/meminfo。

另外，我将粘贴的输出smem -tw，因为这可能确定内存泄漏在内核或应用程序中。

# smem -tw
Area                           Used      Cache   Noncache 
firmware/hardware                 0          0          0 
kernel image                      0          0          0 
kernel dynamic memory      11297432   10738716     558716 
userspace memory            6144832    1182184    4962648 
free memory                15470032   15470032          0 
----------------------------------------------------------
                           32912296   27390932    5521364 

smem帮助我将问题跟踪到了内核，并且我相信NVIDIA驱动程序是罪魁祸首。升级到367.35后，情况看起来不错。

参考文献：

• https://devtalk.nvidia.com/default/topic/952317/huge-memory-leak-/
• /ubuntu/731677/out-of-memory-issue