Eu tenho um servidor que reivindica 1.7 de seus 2 GB de RAM, mas o uso de memória combinada dos processos em execução não chega nem perto desse valor:
$ free -m
total used free shared buffers cached
Mem: 1993 1898 94 0 0 199
-/+ buffers/cache: 1699 294
Swap: 2046 40 2006
$ grep VmRSS /proc/*/status | awk '{s+=$2} END {print s}'
29080
Até agora, as explicações que encontrei culpam o alto uso de RAM em caches e buffers ou o cache slab do kernel , mas nenhum desses parece ser o motivo neste caso (veja também /proc/meminfo abaixo).
O que mais poderia estar causando esse uso excessivo de RAM (o que geralmente faz com que o sistema inicie a troca, mesmo com vm.swappiness = 1)?
O que posso fazer para encontrar e talvez mitigar o motivo?
Informação potencialmente relevante:
O sistema é um servidor dedicado alugado com um CPU Intel Atom N2800 e 2 GB de RAM, como visto acima. Ele está executando o Debian Wheezy (7.6) com o kernel 3.13 do wheezy-backports.
Seu atual /proc/meminfo :
MemTotal: 2041464 kB
MemFree: 95224 kB
Buffers: 20 kB
Cached: 204240 kB
SwapCached: 13000 kB
Active: 100280 kB
Inactive: 132036 kB
Active(anon): 15496 kB
Inactive(anon): 12580 kB
Active(file): 84784 kB
Inactive(file): 119456 kB
Unevictable: 0 kB
Mlocked: 0 kB
SwapTotal: 2096124 kB
SwapFree: 2054960 kB
Dirty: 64 kB
Writeback: 0 kB
AnonPages: 17208 kB
Mapped: 6888 kB
Shmem: 20 kB
Slab: 31180 kB
SReclaimable: 14628 kB
SUnreclaim: 16552 kB
KernelStack: 1848 kB
PageTables: 4556 kB
NFS_Unstable: 0 kB
Bounce: 0 kB
WritebackTmp: 0 kB
CommitLimit: 3116856 kB
Committed_AS: 122748 kB
VmallocTotal: 34359738367 kB
VmallocUsed: 81792 kB
VmallocChunk: 34359611556 kB
HardwareCorrupted: 0 kB
AnonHugePages: 0 kB
HugePages_Total: 0
HugePages_Free: 0
HugePages_Rsvd: 0
HugePages_Surp: 0
Hugepagesize: 2048 kB
DirectMap4k: 136108 kB
DirectMap2M: 1943552 kB
ps -eo pid,user,args,pmem --sort pmem , como Braiam solicitou:
PID USER COMMAND %MEM
2 root [kthreadd] 0.0
3 root [ksoftirqd/0] 0.0
5 root [kworker/0:0H] 0.0
7 root [rcu_sched] 0.0
8 root [rcu_bh] 0.0
9 root [migration/0] 0.0
10 root [watchdog/0] 0.0
11 root [watchdog/1] 0.0
12 root [migration/1] 0.0
13 root [ksoftirqd/1] 0.0
15 root [kworker/1:0H] 0.0
16 root [watchdog/2] 0.0
17 root [migration/2] 0.0
18 root [ksoftirqd/2] 0.0
20 root [kworker/2:0H] 0.0
21 root [watchdog/3] 0.0
22 root [migration/3] 0.0
23 root [ksoftirqd/3] 0.0
25 root [kworker/3:0H] 0.0
26 root [khelper] 0.0
27 root [kdevtmpfs] 0.0
28 root [netns] 0.0
29 root [writeback] 0.0
30 root [kintegrityd] 0.0
31 root [bioset] 0.0
32 root [kblockd] 0.0
35 root [khungtaskd] 0.0
36 root [kswapd0] 0.0
37 root [ksmd] 0.0
38 root [khugepaged] 0.0
39 root [fsnotify_mark] 0.0
40 root [crypto] 0.0
45 root [kthrotld] 0.0
46 root [deferwq] 0.0
151 root [khubd] 0.0
156 root [ata_sff] 0.0
168 root [scsi_eh_0] 0.0
170 root [scsi_eh_1] 0.0
171 root [scsi_eh_2] 0.0
172 root [scsi_eh_3] 0.0
191 root [kworker/3:1H] 0.0
192 root [kworker/1:1H] 0.0
193 root [kworker/0:1H] 0.0
197 root [kworker/2:1H] 0.0
212 root [bioset] 0.0
218 root [btrfs-genwork-1] 0.0
219 root [btrfs-submit-1] 0.0
220 root [btrfs-delalloc-] 0.0
221 root [btrfs-fixup-1] 0.0
224 root [btrfs-rmw-1] 0.0
225 root [btrfs-endio-rai] 0.0
226 root [btrfs-endio-met] 0.0
228 root [btrfs-freespace] 0.0
230 root [btrfs-cache-1] 0.0
231 root [btrfs-readahead] 0.0
233 root [btrfs-qgroup-re] 0.0
234 root [btrfs-cleaner] 0.0
235 root [btrfs-transacti] 0.0
415 root [kworker/2:2] 0.0
533 root [kpsmoused] 0.0
619 root [kworker/3:0] 0.0
1383 root [btrfs-genwork-1] 0.0
1384 root [btrfs-submit-1] 0.0
1385 root [btrfs-delalloc-] 0.0
1386 root [btrfs-fixup-1] 0.0
1389 root [btrfs-rmw-1] 0.0
1390 root [btrfs-endio-rai] 0.0
1391 root [btrfs-endio-met] 0.0
1393 root [btrfs-freespace] 0.0
1395 root [btrfs-cache-1] 0.0
1396 root [btrfs-readahead] 0.0
1398 root [btrfs-qgroup-re] 0.0
1399 root [btrfs-cleaner] 0.0
1400 root [btrfs-transacti] 0.0
1687 root /usr/sbin/sshd 0.0
2087 root [kworker/1:0] 0.0
2218 root [kworker/u8:0] 0.0
2470 root tmux 0.0
2473 root -bash 0.0
4643 root tmux a 0.0
6072 root [kworker/u8:1] 0.0
7126 root [btrfs-worker-2] 0.0
14524 root [btrfs-delayed-m] 0.0
16555 root [kworker/0:2] 0.0
20514 root [btrfs-flush_del] 0.0
22924 root [btrfs-endio-2] 0.0
23031 root [btrfs-worker-3] 0.0
26010 root [btrfs-endio-3] 0.0
26227 root [btrfs-endio-met] 0.0
26383 root [btrfs-delayed-m] 0.0
26823 root [btrfs-endio-wri] 0.0
27063 root [btrfs-endio-met] 0.0
28637 root [kworker/0:0] 0.0
30011 root [kworker/2:0] 0.0
30832 root [btrfs-flush_del] 0.0
31387 root [kworker/1:2] 0.0
31475 root [kworker/3:2] 0.0
31803 root [btrfs-endio-wri] 0.0
32361 root [kworker/1:1] 0.0
499 root lxc-start -d -n io 0.0
1682 sshd /usr/bin/dbus-daemon --syst 0.0
2181 mail /usr/sbin/nullmailer-send - 0.0
13533 root -bash 0.0
19059 root lxc-start -n callisto -d 0.0
20446 root /usr/sbin/sshd 0.0
20693 root /usr/sbin/acpid 0.0
1708 root /sbin/getty 38400 console 0.0
1709 root /sbin/getty 38400 tty1 linu 0.0
1710 root /sbin/getty 38400 tty2 linu 0.0
1711 root /sbin/getty 38400 tty3 linu 0.0
1712 root /sbin/getty 38400 tty4 linu 0.0
1832 root -bash 0.0
2276 root /sbin/getty 38400 tty1 0.0
2277 root /sbin/getty 38400 tty2 0.0
2278 root /sbin/getty 38400 tty3 0.0
2279 root /sbin/getty 38400 tty4 0.0
2280 root /sbin/getty 38400 tty5 0.0
2281 root /sbin/getty 38400 tty6 0.0
13990 root -bash 0.0
20478 root /sbin/getty 38400 console 0.0
20479 root /sbin/getty 38400 tty1 linu 0.0
20480 root /sbin/getty 38400 tty2 linu 0.0
20481 root /sbin/getty 38400 tty3 linu 0.0
20482 root /sbin/getty 38400 tty4 linu 0.0
24167 root -bash 0.0
31031 root -bash 0.0
19067 root init [3] 0.0
2132 root -bash 0.0
4549 root -bash 0.0
1 root init [2] 0.0
2508 root tmux a 0.0
503 root init [3] 0.0
4652 root -bash 0.0
7923 root -bash 0.0
2130 root sshd: root@pts/5 0.0
1824 root ssh io 0.0
2140 root /usr/sbin/cron 0.0
504 root udevd --daemon 0.0
505 root udevd --daemon 0.0
1826 root sshd: root@pts/0 0.0
4544 root sshd: root@pts/0 0.0
381 root udevd --daemon 0.0
16820 root /usr/sbin/vnstatd -d 0.0
14381 root /usr/sbin/sshd 0.0
2224 101 /usr/bin/dbus-daemon --syst 0.0
8182 ntp /usr/sbin/ntpd -p /var/run/ 0.0
2497 nst bash 0.0
6459 root -bash 0.0
2382 root /usr/sbin/console-kit-daemo 0.0
2472 root tmux 0.0
3074 root ps -eo pid,user,args,pmem - 0.0
17115 root /usr/sbin/rsyslogd -c5 0.0
6149 root htop 0.0
3075 root view - 0.1
911 root munin-node 0.1
2231 snmp /usr/sbin/snmpd -Lsd -Lf /d 0.1
13988 root tmux 0.1
26168 root -bash 0.1
27332 root -bash 0.1
628 root -bash 0.1
Tags memory