itech9

Use the “free” command:

$ free [-k]

     total               used               free         shared       buffers         cached
Mem: 127176         122416             4760                     0           21200           67972
-/+ buffers/cache:          33244          93932
Swap:                       0                   0                   0

The real “available if memory full” number is 93932 in the “-/+” line .

If free memory falls too much, Linux will use memory from cached area.

For more details, see:

$ cat /proc/meminfo

MemTotal:             127176 kB
MemFree:                4704 kB
Buffers:               21204 kB
Cached:                68032 kB
SwapCached:                0 kB
Active:                84412 kB
Inactive:              17952 kB
SwapTotal:                 0 kB
SwapFree:                  0 kB
Dirty:                    44 kB
Writeback:                 0 kB
AnonPages:             13148 kB
Mapped:                11988 kB
Slab:                  18068 kB
SReclaimable:          15372 kB
SUnreclaim:             2696 kB
PageTables:              324 kB
NFS_Unstable:              0 kB
Bounce:                    0 kB
CommitLimit:           63588 kB
Committed_AS:          19120 kB
VmallocTotal:         385024 kB
VmallocUsed:             640 kB
VmallocChunk:         384376 kB