Where is linux memory being stolen?

Question

linux

Ubuntu 14.04.1 LTS with all updates installed at the time of writing. Used to broadcast radio using icecast. Works under virtualka vmware esxi 5.5.
Previously worked on real hardware under an older ubuntu, which is probably not so important.
I noticed that the memory began to be completely eaten away (apparently for some reason the icecast version is not very compatible with the ubunta version), but here's what's strange - in ps aux, top, htop it is not clear that the icecast was gobbled up. Moreover, it is not released after restarting icecast, but I am sure that the problem is clearly in it.
Judging by the top, you can see that a total of 45788 kb of memory has been eaten, and free shows 158 mb. And I understand what buffers and cache are, they are clearly not them.

# free
             total       used       free     shared    buffers     cached
Mem:       1017036     239852     777184        504      24968      56804
-/+ buffers/cache:     158080     858956
Swap:      1044476          0    1044476
#

ps aux

icecast   1053  1.8  1.0 308580 10596 ?        S<l  23:16   0:27 /usr/local/bin/icecast -b -c /usr/local/etc/icecast.xml

top

top - 23:45:51 up 29 min,  1 user,  load average: 0.08, 0.08, 0.06
Tasks: 129 total,   1 running, 128 sleeping,   0 stopped,   0 zombie
%Cpu(s):  0.1 us,  0.2 sy,  0.0 ni, 99.6 id,  0.1 wa,  0.0 hi,  0.1 si,  0.0 st
KiB Mem:   1017036 total,   251100 used,   765936 free,    25232 buffers
KiB Swap:  1044476 total,        0 used,  1044476 free.    56856 cached Mem

  PID USER      PR  NI    VIRT    RES    SHR S  %CPU %MEM     TIME+ COMMAND                                                                                                                                              
 1053 icecast   10 -10  308580  10860   2240 S   6.5  1.1   0:32.87 icecast

The amount of free memory in /proc/meminfo is declining, but what exactly is occupying it is not noted.
I suspect that icecast still does this, because it is the only one on the server, but how and why? How to diagnose it?

Answer 1

by a detailed study of /proc/meminfo
I work with a file server with 32gb ram, free on it from the strength of 200-300, everything goes to cache/pagecache

Answer 2

Something I don’t understand what you are complaining about: a gig of memory, 240M of it is used, and the rest is free.
Where? 251100 used is written in top. 777184 is written in free.

Answer 3

Well, drop caches if you really want
sync; echo 3 > /proc/sys/vm/drop_caches
https://www.kernel.org/doc/Documentation/sysctl/vm.txt