cvs commit: src/sys/vm vm_map.c vm_map.h

Mark W. Krentel krentel at
Sun Aug 15 22:34:56 PDT 2004

> Great!  I've been meaning to do this for a while, but the complexity
> was a bit beyond me.  This should greatly increase pipe performance,
> by the way, because pipe buffers are allocated from a single vm_map,
> which accumulates many more entries and much more fragmentation than
> (probably) most other maps in the kernel.

If you (or anyone else) have a real-world application that runs
measurably better with the new vm_map_findspace() algorithm, I'd
love to hear about it, especially if you have numbers.  Probably on
-hackers or something.

I can write a one-page C program that mmap()'s many pages with holes
between them that is a factor of 50-100 faster with the new algorithm
where "many" is around 10,000.  But it's a very artificial micro-


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