[Intel-gfx] [PATCH] drm/i915/gtt: Skip initializing PT with scratch if full

[Mika Kuoppala]

Chris Wilson <chris at chris-wilson.co.uk> writes:

> If we will completely overwrite the PT with PTEs for the object, we can
> forgo filling it with scratch entries.
>
> References: 14826673247e ("drm/i915: Only initialize partially filled pagetables")
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> Cc: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>
> Cc: Mika Kuoppala <mika.kuoppala at linux.intel.com>
> Cc: Matthew Auld <matthew.william.auld at gmail.com>
> Reviewed-by: Matthew Auld <matthew.william.auld at gmail.com>

Reviewed-by: Mika Kuoppala <mika.kuoppala at linux.intel.com>

> ---
>  drivers/gpu/drm/i915/i915_gem_gtt.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
> index daecbf91efc6..6f437b28fe2a 100644
> --- a/drivers/gpu/drm/i915/i915_gem_gtt.c
> +++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
> @@ -1846,7 +1846,8 @@ static int gen6_alloc_va_range(struct i915_address_space *vm,
>  			if (IS_ERR(pt))
>  				goto unwind_out;
>  
> -			gen6_initialize_pt(vm, pt);
> +			if (count < GEN6_PTES)
> +				gen6_initialize_pt(vm, pt);
>  
>  			old = cmpxchg(&ppgtt->base.pd.page_table[pde],
>  				      vm->scratch_pt, pt);
> -- 
> 2.20.1