> VMS had (has?) pageable page tables. I suppose it made sense
> when VMS had to run on machines with 256K (K, not M) of RAM
> but I don't think it makes much sense today.
It might make some difference when you have suspended some
_large_ simulation because the machine is used interactively
during the day, or when you have _loads_ of processes running,
or...
Another concern is that users can grab _all_ of system memory
by having several processes do a 2GB mmap of /dev/zero...
This 'doesn't take any memory' so they can take up as much
(non-pageable) pagetable memory as they want.
In fact, this is the main reason people asked me if I could look
into this... This is one of the biggest denial-of-service holes
still left. (ssstt)
Rik.
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Send Linux memory-management wishes to me: I'm currently looking
for something to hack...