free命令查看内存使用,主要看free和cached是否够用。
root [~] free -m
total used free shared buffers cached
Mem: 3830 3727 103 0 3 2898
-/+ buffers/cache: 825 3005
Swap: 3967 111 3856
total used free shared buffers cached
Mem: 3830 3727 103 0 3 2898
-/+ buffers/cache: 825 3005
Swap: 3967 111 3856
查看详细内存使用,Slab有时候会占用很高。
root [~] cat /proc/meminfo
MemTotal: 7662648 kB
MemFree: 6030756 kB
MemAvailable: 7338432 kB
Buffers: 88144 kB
Cached: 96176 kB
SwapCached: 0 kB
Active: 387132 kB
Inactive: 16588 kB
Active(anon): 220832 kB
Inactive(anon): 5784 kB
Active(file): 166300 kB
Inactive(file): 10804 kB
Unevictable: 0 kB
Mlocked: 0 kB
SwapTotal: 0 kB
SwapFree: 0 kB
Dirty: 80 kB
Writeback: 0 kB
AnonPages: 219400 kB
Mapped: 25916 kB
Shmem: 7216 kB
Slab: 1187744 kB
SReclaimable: 1171768 kB
SUnreclaim: 15976 kB
KernelStack: 2016 kB
PageTables: 5468 kB
NFS_Unstable: 0 kB
Bounce: 0 kB
WritebackTmp: 0 kB
CommitLimit: 3831324 kB
Committed_AS: 456928 kB
VmallocTotal: 34359738367 kB
VmallocUsed: 16200 kB
VmallocChunk: 34359716443 kB
AnonHugePages: 0 kB
HugePages_Total: 0
HugePages_Free: 0
HugePages_Rsvd: 0
HugePages_Surp: 0
Hugepagesize: 2048 kB
DirectMap4k: 22528 kB
DirectMap2M: 7841792 kB
MemTotal: 7662648 kB
MemFree: 6030756 kB
MemAvailable: 7338432 kB
Buffers: 88144 kB
Cached: 96176 kB
SwapCached: 0 kB
Active: 387132 kB
Inactive: 16588 kB
Active(anon): 220832 kB
Inactive(anon): 5784 kB
Active(file): 166300 kB
Inactive(file): 10804 kB
Unevictable: 0 kB
Mlocked: 0 kB
SwapTotal: 0 kB
SwapFree: 0 kB
Dirty: 80 kB
Writeback: 0 kB
AnonPages: 219400 kB
Mapped: 25916 kB
Shmem: 7216 kB
Slab: 1187744 kB
SReclaimable: 1171768 kB
SUnreclaim: 15976 kB
KernelStack: 2016 kB
PageTables: 5468 kB
NFS_Unstable: 0 kB
Bounce: 0 kB
WritebackTmp: 0 kB
CommitLimit: 3831324 kB
Committed_AS: 456928 kB
VmallocTotal: 34359738367 kB
VmallocUsed: 16200 kB
VmallocChunk: 34359716443 kB
AnonHugePages: 0 kB
HugePages_Total: 0
HugePages_Free: 0
HugePages_Rsvd: 0
HugePages_Surp: 0
Hugepagesize: 2048 kB
DirectMap4k: 22528 kB
DirectMap2M: 7841792 kB
slabtop命令,可以根据结果中的SIZE字段查看使用情况。
sync,清理缓存前记得同步内存到磁盘。
root [~] sync
drop_caches,可以进行内存缓存删除,默认是0,1表示清空页缓存,2表示清空inode和目录树缓存,3清空所有的缓存。
root [~] free -m
root [~] sync
root [~] echo 2 > /proc/sys/vm/drop_caches
root [~] free -m
root [~] sync
root [~] echo 2 > /proc/sys/vm/drop_caches
root [~] free -m
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