Memory leek в Ubuntu Server

cat /etc/lsb-release
DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=16.04
DISTRIB_CODENAME=xenial
DISTRIB_DESCRIPTION="Ubuntu 16.04.4 LTS"

uname -a
Linux router 4.4.35-v-ndpi+imq #1 SMP Sat Jan 14 10:35:51 MSK 2017 x86_64 x86_64 x86_64 GNU/Linux

op - 12:35:25 up 211 days, 23:20,  6 users,  load average: 0,09, 0,06, 0,03
Tasks: 167 total,   1 running, 166 sleeping,   0 stopped,   0 zombie
%Cpu(s):  0,5 us,  0,6 sy,  0,0 ni, 97,7 id,  0,0 wa,  0,0 hi,  1,2 si,  0,0 st
КиБ Mem :  4046360 total,   635196 free,  1788316 used,  1622848 buff/cache
КиБ Swap:  1994748 total,  1984824 free,     9924 used.  1869396 avail Mem

  PID USER      PR  NI    VIRT    RES    SHR S  %CPU %MEM     TIME+ COMMAND
25503 aslan     20   0   83956  56268   2980 S   0,0  1,4   4:21.06 tmux: server
25646 root      20   0   37880  19248   3448 S   0,0  0,5   0:01.81 bash
 7475 root      20   0  107884  17752   8784 S   0,0  0,4  25:08.10 vmtoolsd
 7527 root      20   0   65908  13828  11084 S   0,0  0,3   0:00.08 VGAuthService
23800 nobody    20   0  197856  12324   7672 S   0,0  0,3  10:10.48 openvpn
22018 zabbix    20   0  102924   7252   5764 S   0,0  0,2   4:01.44 zabbix_agentd
22015 zabbix    20   0  102752   7184   5968 S   0,0  0,2  52:39.56 zabbix_agentd
22017 zabbix    20   0  102752   7112   5896 S   0,0  0,2  52:29.97 zabbix_agentd
22016 zabbix    20   0  102752   7108   5896 S   0,0  0,2  51:27.11 zabbix_agentd
23767 nobody    20   0   44912   6860   4820 S   0,0  0,2  27:12.27 openvpn
23789 openvpn+  20   0   44404   6396   4932 S   0,0  0,2  32:31.62 openvpn

free
              total        used        free      shared  buff/cache   available
Память:     4046360     1788600      634864       41404     1622896     1869064
Подкачка:     1994748        9924     1984824

awk '/Rss:/{ sum += $2 } END { print sum }' /proc/*/smaps
295092

 Active / Total Objects (% used)    : 831202 / 919124 (90,4%)
 Active / Total Slabs (% used)      : 30255 / 30255 (100,0%)
 Active / Total Caches (% used)     : 75 / 135 (55,6%)
 Active / Total Size (% used)       : 236372,27K / 247444,49K (95,5%)
 Minimum / Average / Maximum Object : 0,01K / 0,27K / 8,00K

  OBJS ACTIVE  USE OBJ SIZE  SLABS OBJ/SLAB CACHE SIZE NAME
104130 104130 100%    1,05K   3471       30    111072K ext4_inode_cache
172368 172056  99%    0,19K   8208       21     32832K dentry
232947 204906  87%    0,10K   5973       39     23892K buffer_head
122157 105078  86%    0,19K   5817       21     23268K kmalloc-192
 22988  22175  96%    0,57K    821       28     13136K radix_tree_node
 12348  12348 100%    0,55K    441       28      7056K inode_cache
 32572  32572 100%    0,12K    958       34      3832K kernfs_node_cache
  3400   3005  88%    0,91K    200       17      3200K ndpi_flows
  4004   3733  93%    0,61K    154       26      2464K proc_inode_cache
   928    853  91%    2,00K     58       16      1856K kmalloc-2048
  7216   6264  86%    0,25K    451       16      1804K kmalloc-256
  1696   1306  77%    1,00K    106       16      1696K kmalloc-1024
  4925   4513  91%    0,31K    197       25      1576K nf_conntrack_1
 24832  16813  67%    0,06K    388       64      1552K kmalloc-64
  2304   2169  94%    0,64K     96       24      1536K shmem_inode_cache
 11936   8897  74%    0,12K    373       32      1492K kmalloc-128
 30090  23096  76%    0,05K    354       85      1416K ftrace_event_field
 34374  20598  59%    0,04K    337      102      1348K ext4_extent_status
   328    305  92%    4,00K     41        8      1312K kmalloc-4096
  5820   5820 100%    0,20K    291       20      1164K vm_area_struct
   310    256  82%    3,19K     31       10       992K task_struct

grep Slab /proc/meminfo
Slab:             251264 kB

awk '{print $1 " " $2 }' /proc/modules | head -5
xt_ndpi 294912
xt_TCPMSS 16384
dccp_diag 16384
dccp 73728
tcp_diag 16384