RE: [Xen-devel] comment request: dom0 dma on large memory systems

["Ian Pratt" <m+Ian.Pratt@xxxxxxxxxxxx>]

> Yes, something like this is obviously required, and 
> introducing a concept of zones seems a sensible way to go. I 
> haven't looked at your patch in great detail but it looks 
> along the right lines. :-)

While working up the patch it's worth bearing in mind the closely
related NUMA issue: We'll want a separate heap for each node's memory,
and a way of requesting a prefered node in the alloc function, falling
back to a 'close' node if req'd.

It might even be worth adding in a zone for ISA DMA memory, so we could
get some old PCMCIA cards working, though probably not worth it.

Ian

 
>   -- Keir
> 
> On 3 Jun 2005, at 08:35, Scott Parish wrote:
> 
> > The attached patch is a (non-functional) prototype of my proposed 
> > solution to the xen. The idea is to add a third MEMZONE for 
> dma'able 
> > memory, change the alloc_domheap_pages() interface so the 
> caller can 
> > request only dma memory if needed. Finally, internal to 
> > common/page_alloc.c, split memory between MEMZONE_DOM and 
> > MEMZONE_DMADOM based on the address.
> >
> >
> > proposed solution to dom0:
> >
> > Dom0 might have memory allocated to it from both high and 
> low memory.
> > The easiest solution would probably be to scan for and 
> preallocate a 
> > chunk of memory that will work for dma, something like what 
> pci-gart.c 
> > does. (or work on letting pci-gart.c work under xen)
> 
> 
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@xxxxxxxxxxxxxxxxxxx
> http://lists.xensource.com/xen-devel
> 

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel