Re: [RFC] Initial alpha-0 for new page allocator API

Christoph Lameter
2006-09-22T16:35:13Z

On Fri, 22 Sep 2006, Andi Kleen wrote:

> On Friday 22 September 2006 06:02, Christoph Lameter wrote:
> > We have repeatedly discussed the problems of devices having varying
> > address range requirements for doing DMA.
>
> We already have such an API. dma_alloc_coherent(). Device drivers
> are not supposed to mess with GFP_DMA* directly anymore for quite
> some time.

Device drivers need to be able to indicate ranges of addresses that may be
different from ZONE_DMA. This is an attempt to come up with a future
scheme that does no longer rely on device drivers referring to zoies.

> > We would like for the device
> > drivers to have the ability to specify exactly which address range is
> > allowed.
>
> I actually have my doubts it is a good idea to add that now. The devices
> with weird requirements are steadily going away

Hmm.... Martin?