Memory management GSoC progress

[Richard Braun]

Hello,

As part of the Google Summer of Code (GSoC) 2015, Justus Winter started
working on replacing the IPC space data structure. He merged radix tree
code into GNU Mach, completely removed the old hash table/splay tree
based code, and made IPC spaces use radix trees instead, which implied
walking over many tricky inline versions of small IPC functions,
historically intended to increase performance on the IPC path when
compilers were bad at inlining.

The result is a strong decrease in fragmentation inside the kernel
memory pool. This was the main goal of reworking IPC spaces. But as
a nice side effect, there is also an increase of overall performance
of about 5-10%. We expect this is caused by removing reverse IPC hash
tables that were previously incorrectly tuned.

I made Debian packages available on my repository for testing :

deb http://ftp.sceen.net/debian-hurd-i386 experimental/
deb-src http://ftp.sceen.net/debian-hurd-i386 experimental/

This code is currently being polished and should be merged soon into
the main gnumach repository.

-- 
Richard Braun

[1] 
https://www.google-melange.com/gsoc/project/details/google/gsoc2015/teythoon/5880308444430336