Linux 内存使用率

文章参考：

1、正确计算linux系统内存使用率

2、Linux系统内存消失与slab使用之谜

例如当前主机内存信息如下：

 1 [zhang@test ~]$ cat /proc/meminfo 
 2 MemTotal:       49294716 kB
 3 MemFree:         1179308 kB
 4 MemAvailable:   26672136 kB
 5 Buffers:          606420 kB
 6 Cached:         14511968 kB
 7 SwapCached:            0 kB
 8 Active:         21935144 kB
 9 Inactive:       11190500 kB
10 Active(anon):   18008032 kB
11 Inactive(anon):      324 kB
12 Active(file):    3927112 kB
13 Inactive(file): 11190176 kB
14 Unevictable:           0 kB
15 Mlocked:               0 kB
16 SwapTotal:             0 kB
17 SwapFree:              0 kB
18 Dirty:              6544 kB
19 Writeback:             0 kB
20 AnonPages:      18007324 kB
21 Mapped:           119976 kB
22 Shmem:              1096 kB
23 Slab:           14501480 kB
24 SReclaimable:   10840908 kB
25 SUnreclaim:      3660572 kB
26 KernelStack:       17184 kB
27 PageTables:        48212 kB
28 NFS_Unstable:          0 kB
29 Bounce:                0 kB
30 WritebackTmp:          0 kB
31 CommitLimit:    24647356 kB
32 Committed_AS:   21739288 kB
33 VmallocTotal:   34359738367 kB
34 VmallocUsed:      117064 kB
35 VmallocChunk:   34359585408 kB
36 HardwareCorrupted:     0 kB
37 AnonHugePages:   5376000 kB
38 HugePages_Total:       0
39 HugePages_Free:        0
40 HugePages_Rsvd:        0
41 HugePages_Surp:        0
42 Hugepagesize:       2048 kB
43 DirectMap4k:      305140 kB
44 DirectMap2M:    50026496 kB

内存使用率计算公式：

1 UsedMem=MemTotal-(MemFree+Buffers+Cached+SReclaimable)
2 内存使用率=UsedMem/MemTotal*100%
3 
4 当前主机内存使用率：
5 49294716-(1179308+606420+14511968+10840908)=22156112
6 22156112/49294716*100%=44.946%