Re: Pre-allocation of shared memory ...

"Andrew Dunstan" <andrew(at)dunslane(dot)net> writes:
> I *know* the latest RH kernel docs *say* they have paranoid mode that
> supposedly guarantees against OOM - it was me that pointed that out
> originally :-). I just checked on the latest sources (today it's RH8, kernel
> 2.4.20-18.8) to be doubly sure, and can't see the patches.

I think you must be looking in the wrong place. Red Hat's kernels have
included the mode 2/3 overcommit logic since RHL 7.3, according to
what I can find. (Don't forget Alan Cox works for Red Hat ;-).)

But it is true that it's not in Linus' tree yet. This may be because
there are still some loose ends. The copy of the overcommit document
in my RHL 8.0 system lists some ToDo items down at the bottom:

To Do
-----
o Account ptrace pages (this is hard)
o Disable MAP_NORESERVE in mode 2/3
o Account for shared anonymous mappings properly
- right now we account them per instance

I have not installed RHL 9 yet --- is the ToDo list any shorter there?

regards, tom lane