Re: [Linaro-mm-sig] [PATCH 1/5] dma-buf: add optional invalidate_mappings callback v2

On Tue, Mar 20, 2018 at 06:47:57PM +0100, Christian König wrote:

Am 20.03.2018 um 15:08 schrieb Daniel Vetter:

...

[SNIP] For the in-driver reservation path (CS) having a slow-path that grabs a temporary reference, drops the vram lock and then locks the reservation normally (using the acquire context used already for the entire CS) is a bit tricky, but totally feasible. Ttm doesn't do that though.

That is exactly what we do in amdgpu as well, it's just not very efficient nor reliable to retry getting the right pages for a submission over and over again.

Out of curiosity, where's that code? I did read the ttm eviction code way back, and that one definitely didn't do that. Would be interesting to update my understanding. -Daniel