https://stackoverflow.com/questions/15140373
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RussianThere is problem in memory model of OpenVZ. When i call malloc(128 * 1024 * 1024) on PC total free memory does not consumed or consumed a little because it not really used by application. But if i call malloc under OpenVZ it is immediately consumes 128Mb of free memory. So when programming for OpenVZ you should no preallocate huge space of memory which not be used.
Consumed memory and process memory not match (140MB vs 8MB)
Question
System memory is consumed by ~140MB after running process, but process took only ~8MB. This process (openttd dedicaded server) is completely standalone (does not communicate with others processes).
Before
free -m
total used free shared buffers cached
Mem: 1000 777 222 0 0 0
-/+ buffers/cache: 777 222
Swap: 0 0 0
After
free -m
total used free shared buffers cached
Mem: 1000 913 86 0 0 0
-/+ buffers/cache: 913 86
Swap: 0 0 0
Process map
pmap 18428 -x
18428: /var/www/ttd-server/openttd_1.2.3 -s null -m null -x -c /var/www/ttd-server /configuration/preload/openttd.cfg -D
Address Kbytes RSS Dirty Mode Mapping
0000000000400000 0 2948 0 r-x-- openttd_1.2.3
0000000000aee000 0 64 48 rw--- openttd_1.2.3
0000000000afe000 0 588 584 rw--- [ anon ]
000000001c66d000 0 2516 2516 rw--- [ anon ]
00002ba83f5a7000 0 100 0 r-x-- ld-2.11.3.so
00002ba83f5c5000 0 256 256 rw--- [ anon ]
00002ba83f7c4000 0 4 4 r---- ld-2.11.3.so
00002ba83f7c5000 0 4 4 rw--- ld-2.11.3.so
00002ba83f7c6000 0 4 4 rw--- [ anon ]
00002ba83f7c7000 0 380 0 r-x-- libstdc++.so.6.0.13
00002ba83f8bd000 0 0 0 ----- libstdc++.so.6.0.13
00002ba83fabd000 0 28 28 r---- libstdc++.so.6.0.13
00002ba83fac4000 0 8 8 rw--- libstdc++.so.6.0.13
00002ba83fac6000 0 4 4 rw--- [ anon ]
00002ba83fadb000 0 52 0 r-x-- libpthread-2.11.3.so
00002ba83faf2000 0 0 0 ----- libpthread-2.11.3.so
00002ba83fcf1000 0 4 4 r---- libpthread-2.11.3.so
00002ba83fcf2000 0 4 4 rw--- libpthread-2.11.3.so
00002ba83fcf3000 0 8 8 rw--- [ anon ]
00002ba83fcf8000 0 112 0 r-x-- libm-2.11.3.so
00002ba83fd78000 0 0 0 ----- libm-2.11.3.so
00002ba83ff78000 0 4 4 r---- libm-2.11.3.so
00002ba83ff79000 0 4 4 rw--- libm-2.11.3.so
00002ba83ff7a000 0 460 0 r-x-- libc-2.11.3.so
00002ba8400d3000 0 0 0 ----- libc-2.11.3.so
00002ba8402d2000 0 16 16 r---- libc-2.11.3.so
00002ba8402d6000 0 4 4 rw--- libc-2.11.3.so
00002ba8402d7000 0 16 16 rw--- [ anon ]
00002ba8402dc000 0 16 0 r-x-- libgcc_s.so.1
00002ba8402f2000 0 0 0 ----- libgcc_s.so.1
00002ba8404f1000 0 4 4 rw--- libgcc_s.so.1
00002ba8404f2000 0 104 104 rw--- [ anon ]
00002ba848565000 0 284 284 rw--- [ anon ]
00007fff900e4000 0 44 44 rw--- [ stack ]
00007fff901fd000 0 8 0 r-x-- [ anon ]
ffffffffff600000 0 0 0 ----- [ anon ]
---------------- ------ ------ ------
total kB 162884 8048 3952
top before (sorted by RES)
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
15801 www-data 17 0 1320m 173m 4036 S 1.3 17.4 0:54.75 java
1518 ejabberd 15 0 99684 54m 3724 S 0.0 5.5 18:05.64 beam
7917 www-data 15 0 124m 47m 2204 S 0.0 4.8 0:02.43 plackup
8039 www-data 15 0 123m 46m 2204 S 0.0 4.7 0:02.38 plackup
32439 www-data 15 0 116m 42m 2812 S 0.0 4.2 0:42.54 plackup
29708 mysql 15 0 170m 38m 7556 S 0.0 3.9 187:51.36 mysqld
32247 www-data 15 0 141m 38m 3376 S 0.0 3.8 0:08.01 plackup
6025 www-data 15 0 176m 37m 4532 S 0.0 3.7 0:06.17 php-cgi
3248 www-data 15 0 172m 33m 4544 S 0.0 3.4 0:10.55 php-cgi
3591 www-data 15 0 123m 32m 3080 S 0.0 3.3 9:09.46 plackup
32303 www-data 15 0 250m 32m 6364 S 0.3 3.3 17:54.92 mongod
24324 send2me 16 0 53340 14m 3088 S 0.0 1.5 0:03.00 perl
26584 bind 25 0 93800 11m 2352 S 0.0 1.1 0:00.17 named
20045 root 15 0 110m 9288 6876 S 0.0 0.9 2:18.20 ispmgr
15574 www-data 18 0 144m 9168 5732 S 0.0 0.9 0:00.07 php-cgi
30220 www-data 15 0 37420 9148 2936 S 0.0 0.9 1:29.11 websockify.py
9935 root 16 0 83864 3688 2856 S 0.0 0.4 0:00.02 sshd
top after (sorted by RES):
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
15801 www-data 17 0 1320m 173m 4036 S 1.3 17.4 0:53.77 java
1518 ejabberd 15 0 99684 54m 3724 S 0.0 5.5 18:05.62 beam
7917 www-data 15 0 124m 47m 2204 S 0.0 4.8 0:02.42 plackup
8039 www-data 15 0 123m 46m 2204 S 0.0 4.7 0:02.37 plackup
32439 www-data 15 0 116m 42m 2812 S 0.0 4.2 0:42.54 plackup
29708 mysql 15 0 170m 38m 7556 S 0.0 3.9 187:51.34 mysqld
32247 www-data 15 0 141m 38m 3376 S 0.0 3.8 0:08.01 plackup
6025 www-data 15 0 176m 37m 4532 S 0.0 3.7 0:06.17 php-cgi
3248 www-data 15 0 172m 33m 4544 S 0.0 3.4 0:10.55 php-cgi
3591 www-data 15 0 123m 32m 3080 S 0.0 3.3 9:09.44 plackup
32303 www-data 15 0 250m 32m 6364 R 0.3 3.3 17:54.61 mongod
24324 send2me 16 0 53340 14m 3088 S 0.0 1.5 0:03.00 perl
26584 bind 25 0 93800 11m 2352 S 0.0 1.1 0:00.17 named
20045 root 15 0 110m 9288 6876 S 0.0 0.9 2:18.19 ispmgr
15574 www-data 18 0 144m 9168 5732 S 0.0 0.9 0:00.07 php-cgi
30220 www-data 15 0 37420 9148 2936 S 0.0 0.9 1:29.11 websockify.py
18428 www-data 16 0 151m 8048 4096 R 0.0 0.8 0:00.30 openttd_1.2.3
9935 root 16 0 83864 3688 2856 S 0.0 0.4 0:00.02 sshd
Looks like virtual memory of process located in physical memory, but why? For example java process have 1320MB of virtual memory but consumed only 173MB of real (mathced with RES), but openttd process have RES=8MB but consumes 136MB of real memory. What this is mean?
UPD.
My server is based on OpenVZ.
Openttd compiled in single threaded mode.
On the real PC there are no problem.
ulimit -a
core file size (blocks, -c) 0
data seg size (kbytes, -d) unlimited
scheduling priority (-e) 0
file size (blocks, -f) unlimited
pending signals (-i) 16382
max locked memory (kbytes, -l) 64
max memory size (kbytes, -m) unlimited
open files (-n) 1024
pipe size (512 bytes, -p) 8
POSIX message queues (bytes, -q) 819200
real-time priority (-r) 0
stack size (kbytes, -s) 128
cpu time (seconds, -t) unlimited
max user processes (-u) unlimited
virtual memory (kbytes, -v) unlimited
file locks (-x) unlimited
Solution
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