Some mmap observations compared to Linux 2.6/OpenBSD

[Q]

Yes, it would appear this is a legacy thing that existed in the original
1994 import of the BSD 4.4 Lite source. Both FreeBSD and NetBSD still
use this technique, but OpenBSD changed to using Red-Black trees back in
Feb 2002. 

The actual commit quote reads:

"use a red-black tree to find entries in the vm_map. augment the red-black
tree to find free space between entries.  speeds up memory allocation,
etc..."


I am wondering if there is a compelling reason why the technique used by
OpenBSD could not be adapted to FreeBSD's VM system.

Seeya...Q

On Wed, 2003-10-22 at 19:57, Kris Kennaway wrote:

> On Wed, Oct 22, 2003 at 07:51:28PM +1000, Q wrote:
> > Thanks, I have already looked over the repositories to determine how
> > they differed. I wasn't really asking about the history of these changes
> > in the other projects, but rather the history of why FreeBSD HASN'T also
> > gone down this road. There doesn't appear to be anything in CVS or the
> > mail archives that I can find that would indicate any intention to
> > change the current implementation.
> 
> I'm assuming that FreeBSD has some version of the historical BSD
> implementation, and the change was made in OpenBSD (or perhaps NetBSD
> before the split), and it has not been considered before in FreeBSD.
> I have no familiarity with the code in question, however.
> 
> Kris