shared memory

Dale Farnsworth df at phx.mcd.mot.com
Thu Dec 14 10:59:00 AEST 1989


Chris Torek (chris at mimsy.umd.edu) writes:
> 
> As I understand it---which is not to say that it is so, for I have
> never seen the SysRel% 1, 2, or 3# code itself---the total amount of
> shared memory allowed per-system is reserved at boot time, is not
> pageable, and is effectively taken away from the rest of the system.
> For processes not using it, it is as if some of the machine's memory
> had been physically removed.
> 
> This would mitigate against raising SHMMAX arbitrarily....

I'm glad you started with a disclaimer.  I've seen several System V shared
memory implementations, and *none* of them reserve shared memory at boot
time.  If the system supports paging, the shared memory is paged as well.

-Dale

-- 
Dale Farnsworth



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