Linux 查看 memory info

通過 meminfo 文件查看

root@aliyun:~# ll -h /proc/meminfo
-r--r--r-- 1 root root 0 Jun 18 14:11 /proc/meminfo  注意這個內存文件大小爲 0
root@aliyun:~# cat /proc/meminfo
MemTotal:        2041256 kB    # 1093M            $$$ total      
MemFree:          221828 kB    #  216M            $$$ free   
MemAvailable:    1553252 kB    # 1516.8M          $$$ available
Buffers:          185624 kB    # 181M             $$$ buffers  kernel buffers
Cached:          1183072 kB    # 1155.3M          $$$ cache      page cache
SwapCached:            0 kB
Active:           748952 kB    # 731.4M
Inactive:         872508 kB    # 70.8M
Active(anon):     159244 kB    # 155.5M
Inactive(anon):    96264 kB    # 94M
Active(file):     589708 kB    # 575.9M
Inactive(file):   776244 kB    # 758M
Unevictable:           0 kB
Mlocked:               0 kB
SwapTotal:        969964 kB    # 947M
SwapFree:         969964 kB    # 947M
Dirty:                48 kB
Writeback:             0 kB
AnonPages:        252788 kB    # 246.9M
Mapped:            78052 kB    # 76M
Shmem:              2744 kB                        $$$ shared       
Slab:             165868 kB    # 162M
SReclaimable:     149608 kB    #146M               $$$ cache    slabs
SUnreclaim:        16260 kB    # 15.9M
KernelStack:        2652 kB
PageTables:         4384 kB
NFS_Unstable:          0 kB
Bounce:                0 kB
WritebackTmp:          0 kB
CommitLimit:     1990592 kB    # 1944M
Committed_AS:     841632 kB    # 822M
VmallocTotal:   34359738367 kB # 32T
VmallocUsed:           0 kB
VmallocChunk:          0 kB
HardwareCorrupted:     0 kB
AnonHugePages:         0 kB
ShmemHugePages:        0 kB
ShmemPmdMapped:        0 kB
CmaTotal:              0 kB
CmaFree:               0 kB
HugePages_Total:       0
HugePages_Free:        0
HugePages_Rsvd:        0
HugePages_Surp:        0
Hugepagesize:       2048 kB
DirectMap4k:       67456 kB   # 66M
DirectMap2M:     2029568 kB   #1982M
DirectMap1G:           0 kB

通過 free 命令查看

free 版本

root@aliyun:~# free -V
free from procps-ng 3.3.12

root@aliyun:~# free --wide
              total        used        free      shared     buffers       cache   available
Mem:        2041256      294760      220628        2736      188120     1337748     1556388
Swap:        969964           0      969964

meminfo 和 free 對應關係

free	physical	swap
total	MemTotal	SwapTotal
used	used = total - free - buffers - cache
free	MemFree	SwapFree
shared	Shmem
buffers	buffers
cache	Cached、SReclaimable
buffer/cache	buffer/cache = buffers + cache
avaliable	MemAvailable

References

1. https://man7.org/linux/man-pages/man1/free.1.htm
2. memory map of a process
3. Linux 喫掉很多內存
4. meminfo