[Intel-gfx] [PATCH 00/26] [RFCish] GEN7 dynamic page tables

[Chris Wilson]

On Mon, Mar 17, 2014 at 10:48:32PM -0700, Ben Widawsky wrote:
> Okay, so what does this do?
> The patch series /dynamicizes/ page table allocation and teardown for
> GEN7. It also starts to introduce GEN8, but the tricky stuff is still
> not done. Up until now, all our page tables are pre-allocated when the
> address space is created. That's actually okay for current GENs since we
> don't use many address spaces, and the page tables occupy only 2MB each.
> However, on GEN8 we can use a deeper page table, and to preallocate such
> an address space would be very costly. This work was done for GEN7 first
> because this is the most well tested with full PPGTT, and stable
> platforms are readily available.
> 
> In this patch series, I've demonstrated how we will manage tracking used
> page tables (bitmaps), and broken things out into much more discrete
> functions. I'm hoping I'll get feedback on the way I've implemented
> things (primarily if it seems fundamentally flawed in any way). The real
> goal was to prove out the dynamic allocation so we can begin to enable
> GEN8 in the same way. I'll emphasize now that I put in a lot of effort
> limit risk with each patch, and this does result in some excess churn.

I like it.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre