Estou tentando descobrir o que exatamente usa a memória swap no meu sistema. Relatórios gratuitos sobre 5GB de memória swap usada, mas todos os processos usam apenas 24MB de swap. Eu suspeito que swap possa ser usado por um sistema de arquivos tmpfs, mas eu não sei como verificar isso.
Você seria tão gentil em dizer o que mais eu deveria verificar para examinar o conteúdo da memória swap, por favor?
# free -m
total used free shared buffers cached
Mem: 48206 47688 518 8177 10 11789
-/+ buffers/cache: 35888 12317
Swap: 15999 5378 10621
VmSwap de / proc / * / status
# grep "VmSwap:" /proc/*/status | awk '{swapped+=$2} END {print swapped/1024" MB"}'
23.8438 MB
# grep "VmSwap:" /proc/*/status | grep -v " 0 kB"
/proc/1/status:VmSwap: 52 kB
/proc/27714/status:VmSwap: 956 kB
/proc/27718/status:VmSwap: 948 kB
/proc/27722/status:VmSwap: 820 kB
/proc/27723/status:VmSwap: 804 kB
/proc/27724/status:VmSwap: 812 kB
/proc/27725/status:VmSwap: 804 kB
/proc/29636/status:VmSwap: 760 kB
/proc/29640/status:VmSwap: 960 kB
/proc/29642/status:VmSwap: 1948 kB
/proc/29643/status:VmSwap: 936 kB
/proc/29647/status:VmSwap: 1624 kB
/proc/29649/status:VmSwap: 872 kB
/proc/3750/status:VmSwap: 116 kB
/proc/3770/status:VmSwap: 228 kB
/proc/3790/status:VmSwap: 260 kB
/proc/3810/status:VmSwap: 444 kB
/proc/3823/status:VmSwap: 164 kB
/proc/4022/status:VmSwap: 2296 kB
/proc/4037/status:VmSwap: 640 kB
/proc/4049/status:VmSwap: 572 kB
/proc/4058/status:VmSwap: 592 kB
/proc/4068/status:VmSwap: 260 kB
/proc/4081/status:VmSwap: 192 kB
/proc/4095/status:VmSwap: 56 kB
/proc/4110/status:VmSwap: 76 kB
/proc/4112/status:VmSwap: 80 kB
/proc/4114/status:VmSwap: 76 kB
/proc/4116/status:VmSwap: 80 kB
/proc/4118/status:VmSwap: 80 kB
/proc/4120/status:VmSwap: 76 kB
/proc/4127/status:VmSwap: 2068 kB
/proc/4128/status:VmSwap: 2068 kB
/proc/7655/status:VmSwap: 312 kB
/proc/7661/status:VmSwap: 380 kB
/proc/905/status:VmSwap: 840 kB
tmpfs
# mount | grep tmpfs
tmpfs on /dev/shm type tmpfs (rw,rootcontext="system_u:object_r:tmpfs_t:s0")
/ proc / meminfo
# cat /proc/meminfo
MemTotal: 49363344 kB
MemFree: 700676 kB
Buffers: 11000 kB
Cached: 11822364 kB
SwapCached: 522436 kB
Active: 37945008 kB
Inactive: 4986964 kB
Active(anon): 35707220 kB
Inactive(anon): 3720092 kB
Active(file): 2237788 kB
Inactive(file): 1266872 kB
Unevictable: 0 kB
Mlocked: 0 kB
SwapTotal: 16383992 kB
SwapFree: 10875936 kB
Dirty: 224072 kB
Writeback: 0 kB
AnonPages: 30580752 kB
Mapped: 12218972 kB
Shmem: 8328572 kB
Slab: 270104 kB
SReclaimable: 181768 kB
SUnreclaim: 88336 kB
KernelStack: 4256 kB
PageTables: 91528 kB
NFS_Unstable: 0 kB
Bounce: 0 kB
WritebackTmp: 0 kB
CommitLimit: 41065664 kB
Committed_AS: 49589524 kB
VmallocTotal: 34359738367 kB
VmallocUsed: 5203000 kB
VmallocChunk: 34327589304 kB
HardwareCorrupted: 0 kB
AnonHugePages: 5289984 kB
HugePages_Total: 0
HugePages_Free: 0
HugePages_Rsvd: 0
HugePages_Surp: 0
Hugepagesize: 2048 kB
DirectMap4k: 31952556 kB
DirectMap2M: 17270784 kB
DirectMap1G: 1048576 kB
Problema resolvido, encontrei uma informação de que 1372500 páginas de memória compartilhada foram trocadas:
# ipcs -mu
------ Shared Memory Status --------
segments allocated 32
pages allocated 2752532
pages resident 1380020
pages swapped 1372500
Swap performance: 0 attempts 0 successes
# getconf PAGESIZE
4096
# echo $((1372500*4096/1024/1024))
5361
Descobri que 1372500 páginas de memória compartilhada são trocadas. O tamanho da página é de 4096 bytes.
# ipcs -mu
------ Shared Memory Status --------
segments allocated 32
pages allocated 2752532
pages resident 1380020
pages swapped 1372500
Swap performance: 0 attempts 0 successes
# getconf PAGESIZE
4096
# echo "$((1372500*4096/1024/1024)) MB"
5361 MB
Uso de troca por processo
#!/bin/bash
set -o posix
set -u
SUM=0
OVERALL=0
for DIR in 'find /proc/ -maxdepth 1 -type d -regex "^/proc/[0-9]+"' ; do
PID='echo $DIR | cut -d / -f 3'
PROGNAME='ps -p $PID -o comm --no-headers'
for SWAP in 'grep Swap $DIR/smaps 2>/dev/null| awk '{ print $2 }''
do
let SUM=$SUM+$SWAP
done
echo "PID=$PID - Swap used: $SUM - ($PROGNAME )"
let OVERALL=$OVERALL+$SUM
SUM=0
done
echo "Overall swap used: $OVERALL"
O Linux move a memória acessada com pouca frequência para trocar; nem sempre importa se você tem memória livre ou não no momento, veja esta resposta em uma pergunta semelhante no askubuntu: link
Eu uso esse bash para ver quais processos em swap - for file in /proc/*/status ; do awk '/VmSwap|Name/{printf $2 " " $3}END{ print ""}' $file; done | sort -k 2 -n -r | less