Subject: README: significant pmap improvements committed
To: None <port-alpha@NetBSD.ORG>
From: Jason Thorpe <>
List: port-alpha
Date: 03/11/1998 17:38:26
Hi folks...

I have just committed some significant improvements to the NetBSD/alpha
pmap module.  The major change is that I have completely rewritten how
page tables are managed.  The new method is considerably more efficient
in terms of kernel virtual address space use and in terms of physical
memory use.  A typical kernel will now have an additional ~1.3MB of free
memory to play with.  Combined with the MACHINE_NEW_NONCONTIG stuff
Chris Demetriou and I did about a month ago, this totals to around 2.5MB
of additional free memory on typical systems.

The page table management changes also allow for a much larger user
address space (4TB), and a much larger value for maxproc.  This means
that after your next kernel update, you can feel free to bump maxusers
up to larger values in your kernel config files (I'm currently running
with "maxusers 64" on my AlphaStation 500).

Among other things, the larger user address space will allow someone
to implement shared library support for COMPAT_OSF1.

I'd like to express my thanks to Chris Demetriou and Ross Harvey who
provided a great deal of helpful insight and debugging assistance.

I have found this new code to be quite stable, but if you encounter any
problems, please let me know by sending a bug report with send-pr(1).

Jason R. Thorpe                             
NASA Ames Research Center                            Home: +1 408 866 1912
NAS: M/S 258-5                                       Work: +1 650 604 0935
Moffett Field, CA 94035                             Pager: +1 415 428 6939