[Intel-gfx] [PATCH 6/7] drm/i915: Avoid evicting user fault mappable vma for pread/pwrite

[Joonas Lahtinen]

On Mon, 2017-10-09 at 09:44 +0100, Chris Wilson wrote:
> Both pread/pwrite GTT paths provide a fast fallback in case we cannot
> map the whole object at a time. Currently, we use the fallback for very
> large objects and for active objects that would require remapping, but
> we can also add active fault mappable objects to the list that we want
> to avoid evicting. The rationale is that such fault mappable objects are
> in active use and to evict requires tearing down the CPU PTE and forcing
> a page fault on the next access; more costly, and intefers with other
> processes, than our per-page GTT fallback.
> 
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>

Reviewed-by: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>

Regards, Joonas
-- 
Joonas Lahtinen
Open Source Technology Center
Intel Corporation