diff mbox

[2/2] drm/i915: Skip final clflush if LLC is coherent

Message ID 20161114085453.16384-2-chris@chris-wilson.co.uk (mailing list archive)
State New, archived
Headers show

Commit Message

Chris Wilson Nov. 14, 2016, 8:54 a.m. UTC 
If the LLC is coherent with the object, we do not need to worry about
whether main memory and cache mismatch when we hand the object back to
the system.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
---
 drivers/gpu/drm/i915/i915_gem.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

Comments

Ville Syrjälä Nov. 14, 2016, 1:57 p.m. UTC | #1 
On Mon, Nov 14, 2016 at 08:54:53AM +0000, Chris Wilson wrote:
> If the LLC is coherent with the object, we do not need to worry about
> whether main memory and cache mismatch when we hand the object back to
> the system.
> 
> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

Makes sense to me.

Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>

> ---
>  drivers/gpu/drm/i915/i915_gem.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
> index 4931bfcff2a2..3b021e9e3379 100644
> --- a/drivers/gpu/drm/i915/i915_gem.c
> +++ b/drivers/gpu/drm/i915/i915_gem.c
> @@ -228,7 +228,8 @@ __i915_gem_object_release_shmem(struct drm_i915_gem_object *obj,
>  	if (obj->mm.madv == I915_MADV_DONTNEED)
>  		obj->mm.dirty = false;
>  
> -	if ((obj->base.read_domains & I915_GEM_DOMAIN_CPU) == 0)
> +	if ((obj->base.read_domains & I915_GEM_DOMAIN_CPU) == 0 &&
> +	    !cpu_cache_is_coherent(obj->base.dev, obj->cache_level))
>  		drm_clflush_sg(pages);
>  
>  	obj->base.read_domains = I915_GEM_DOMAIN_CPU;
> -- 
> 2.10.2
> 
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/intel-gfx
diff mbox

Patch

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 4931bfcff2a2..3b021e9e3379 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -228,7 +228,8 @@  __i915_gem_object_release_shmem(struct drm_i915_gem_object *obj,
 	if (obj->mm.madv == I915_MADV_DONTNEED)
 		obj->mm.dirty = false;
 
-	if ((obj->base.read_domains & I915_GEM_DOMAIN_CPU) == 0)
+	if ((obj->base.read_domains & I915_GEM_DOMAIN_CPU) == 0 &&
+	    !cpu_cache_is_coherent(obj->base.dev, obj->cache_level))
 		drm_clflush_sg(pages);
 
 	obj->base.read_domains = I915_GEM_DOMAIN_CPU;