Maximum size of system V shared memory segment that can be created. This parameter is an upper limit that is checked before the system sees if it actually has the physical resources to create the requested memory segment.
0 - MAXINT on 32-bit systems, MAXINT64 on 64-bit systems
No. Loaded into shmmax field of shminfo structure.
When the default value is too low. Generally changed at the recommendation of software vendors, but unless the size of a shared memory segment needs to be constrained, setting this parameter to the maximum possible value has no side effects.