Unless I am wrong. the value of
/proc/sys/kernel/shmall indicates the the total amount of shared memory, in bytes, that can be allocated to the system.
I am on a
t2.micro ec2 debian instance, and I get this:
$ cat /proc/sys/kernel/shmall 18446744073692774399
I do not suppose this means that the total allocatable amount of shared memory is around 0.02 zettabytes ...