how much RAM is available for our kernel?

To find out about memory use, we can look at a proc file, MemInfo. If we look at the beginning of the file, the head of it, we see it reports MemTotal. So this particular box has, like, 16 gig. Incidentally, this is the memory available when you boot Linux, you could tell it how much memory to use, and that can be less than the amount of physical RAM in the system.

 

[fullname@localhost boot]$ head /proc/meminfo
MemTotal:       24626616 kB
MemFree:        23548284 kB
MemAvailable:   23749780 kB
Buffers:            1280 kB
Cached:           363384 kB
SwapCached:            0 kB
Active:           508508 kB
Inactive:         291144 kB
Active(anon):     435632 kB
Inactive(anon):     9880 kB
[fullname@localhost boot]$

 

[fullname@localhost boot]$ free
total        used        free      shared  buff/cache   available
Mem:       24626616      645880    23547972       10448      432764    23749488
Swap:       1265660           0     1265660
[fullname@localhost boot]$