/proc/meminfo

# cat /etc/redhat-release
CentOS Linux release 7.5.1804 (Core)
# uname -a
Linux master 3.10.0-862.14.4.el7.x86_64 #1 SMP Wed Sep 26 15:12:11 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux
# cat /proc/meminfo
MemTotal:         499316 kB
MemFree:            6552 kB
MemAvailable:     203752 kB
Buffers:               0 kB
Cached:           189456 kB
SwapCached:        41296 kB
Active:           190144 kB
Inactive:         214860 kB
Active(anon):      97236 kB
Inactive(anon):   119776 kB
Active(file):      92908 kB
Inactive(file):    95084 kB
Unevictable:           0 kB
Mlocked:               0 kB
SwapTotal:       1048572 kB
SwapFree:         841724 kB
Dirty:                 0 kB
Writeback:             0 kB
AnonPages:        195556 kB
Mapped:            30960 kB
Shmem:              1464 kB
Slab:              53272 kB
SReclaimable:      22320 kB
SUnreclaim:        30952 kB
KernelStack:        3024 kB
PageTables:         6128 kB
NFS_Unstable:          0 kB
Bounce:                0 kB
WritebackTmp:          0 kB
CommitLimit:     1298228 kB
Committed_AS:    1183944 kB
VmallocTotal:   34359738367 kB
VmallocUsed:        9576 kB
VmallocChunk:   34359723772 kB
HardwareCorrupted:     0 kB
AnonHugePages:         0 kB
CmaTotal:              0 kB
CmaFree:               0 kB
HugePages_Total:       0
HugePages_Free:        0
HugePages_Rsvd:        0
HugePages_Surp:        0
Hugepagesize:       2048 kB
DirectMap4k:      114680 kB
DirectMap2M:      409600 kB

• MemAvailable
  • 従来は MemFree 項目と Buffers 項目、 Cached 項目の数字を足したものが利用可能なメモリとして概算する必要があったが、 MemAvailable の項目ができて一目瞭然になった