Re: [Intel-gfx] [PATCH v9 5/7] vfio: Define vfio based dma-buf operations

[Gerd Hoffmann]

On Fri, 2017-06-23 at 15:49 +0800, Zhi Wang wrote:
> Hi:
> ÂÂÂÂÂThanks for the discussions! If the userspace application hasÂ
> already maintained a LRU list, it looks like we don't need
> generationÂ
> anymore,

generation isn't required, things are working just fine without that. 
It is just a small optimization, userspace can skip the LRU lookup
altogether if the generation didn't change.

But of couse that only pays off if the kernel doesn't has to put much
effort into maintaining the generation id.  Something simple like
increasing it each time the guest writes a register which affects
plane_info.

If you think it doesn't make sense from the driver point of view we can
drop the generation.

cheers,
  Gerd