malloc changes

[jd]

FYI,

FreeBSD just imported a new malloc to replace the aged 
phkmalloc.

There was much back and forth with the author and David Xu
so he might have an opinion as to whether the changes in the
FreeBSD malloc are worth looking into.

The new malloc is not derived from the phkmalloc so likely
these changes would not apply.  Many of the features are
similar, except the new jemalloc was engineered with true
concurrent threaded applications in mind.