[patch] malloc per-thread cache ready for review

[DJ Delorie]

Markus Trippelsdorf <markus@trippelsdorf.de> writes:
> http://locklessinc.com/downloads/lockless_allocator_src.tgz (the best in
> my testing) or jemalloc.

Before we go down the "which allocator is best" road... glibc's
allocator is intended to be a general purpose "reasonably good enough"
system allocator.  It's easy to find a specific allocator that beats it
in a specific test, but being a specifically best allocator is not our
goal here - providing an allocator that can be the default on a
Linux-based system is.

Hence, my goal with the per-thread cache is to make it "generally
better" for overall system performance.

I am not trying to make it better than every other allocator in every
case, that's a futile exercise.