Subject: Re: SGMAP DMA improvements
To: Jason R Thorpe <>
From: Matthew Jacob <>
List: port-alpha
Date: 07/19/2001 10:21:41
On Thu, 19 Jul 2001, Jason R Thorpe wrote:

> Folks...
> I finally had the correct combination of "time" and "motivation" to
> hack on the SGMAP DMA code a little, and get it working more the way
> I'd like.
> Why do you care?
> Well, for those of you who have more memory than the direct-mapped DMA
> window can address (this is usually ">1G" or ">2G"), then you can now
> use all that memory.  It previously didn't work properly because I had
> not yet implemented mbuf support in the SGMAP routines.

Awesome - I think Kevin and I were wondering about this quite a while back!

> That is now fixed, and the routines are a bit more efficient -- I've
> tested it by using all SGMAPs for all DMA on my AlphaServer 1200.
> There is another optimization I plan on making, but it's not that
> important right now.
> I will be building a binary snapshot shortly that includes these
> improvements.

Very good!