Re: ttm: merge ttm_backend & ttm_tt, introduce ttm dma allocator

[Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>]

On Thu, Nov 03, 2011 at 07:39:04PM -0400, j.glisse@gmail.com wrote:
> Hi,
> 
> So updated patchset, only patch 5 seen change since last set.
> Last 3 patch are from your patchset, modified on top of mine.

Yup, and I've tested it on my radeon box. Going to test it
on the nvidia and some of the 32-bit troublesome cards.

Will need a patch to enable the TTM DMA under the nouveau
driver too, but I can spin that up.

> 
> Konrad so i added you dma pool allocator on top of that
> and added support for it to radeon. All in all it's slightly
> smaller than your patchset.

It is! Thank you.
> 
> Biggest change is use of a list_head in ttm_tt to keep the
> dma_page list inside the ttm_tt object allowing faster and
> lot simpler deallocation of page.

Yup.
> 
> I only briefly test this code, it seems ok so far. Did you
> tested booting kernel with swiotlb=force and with your patchset ?
> Because here it doesn't work. I still don't understand why
> swiotlb want to create a bounce page when the page supplied
> fit the constraint. Need to dig into kernel history to see if
> there is any good reasons for that.

I think you found out why.. the force, does force every page.

> 
> Otherwise i believe this whole patchset make things cleaner
> and simpler for ttm.

<nods> So do I.

Let me run it throught some of the machines this week to get
that extra comfortable feeling.

> 
> Cheers,
> Jerome Glisse