[Intel-gfx] [PATCH 2/9] drm/i915: Use insert_page for pwrite_fast

[Chris Wilson]

On Mon, Dec 14, 2015 at 09:54:06AM +0000, Chris Wilson wrote:
> On Mon, Dec 14, 2015 at 11:16:04AM +0530, ankitprasad.r.sharma at intel.com wrote:
> > From: Ankitprasad Sharma <ankitprasad.r.sharma at intel.com>
> > 
> > In pwrite_fast, map an object page by page if obj_ggtt_pin fails. First,
> > we try a nonblocking pin for the whole object (since that is fastest if
> > reused), then failing that we try to grab one page in the mappable
> > aperture. It also allows us to handle objects larger than the mappable
> > aperture (e.g. if we need to pwrite with vGPU restricting the aperture
> > to a measely 8MiB or something like that).
> > 
> > v2: Pin pages before starting pwrite, Combined duplicate loops (Chris)
> > 
> > v3: Combined loops based on local patch by Chris (Chris)
> > 
> > v4: Added i915 wrapper function for drm_mm_insert_node_in_range (Chris)
> > 
> > Signed-off-by: Ankitprasad Sharma <ankitprasad.r.sharma at intel.com>
> > Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> > ---
> >  drivers/gpu/drm/i915/i915_gem.c | 86 ++++++++++++++++++++++++++++++-----------
> >  1 file changed, 64 insertions(+), 22 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
> > index bf7f203..46c1e75 100644
> > --- a/drivers/gpu/drm/i915/i915_gem.c
> > +++ b/drivers/gpu/drm/i915/i915_gem.c
> > @@ -61,6 +61,21 @@ static bool cpu_write_needs_clflush(struct drm_i915_gem_object *obj)
> >  	return obj->pin_display;
> >  }
> >  
> > +static int
> > +i915_gem_insert_node_in_range(struct drm_i915_private *i915,
> > +			      struct drm_mm_node *node, u64 size,
> > +			      unsigned alignment, u64 start, u64 end)
> > +{
> > +	int ret;
> > +
> > +	ret = drm_mm_insert_node_in_range_generic(&i915->gtt.base.mm, node,
> > +						  size, alignment, 0, start,
> > +						  end, DRM_MM_SEARCH_DEFAULT,
> > +						  DRM_MM_SEARCH_DEFAULT);
> > +
> > +	return ret;
> > +}
> 
> No. It encodes a very bad assumption (i915->gtt) that is not made clear
> in anyway.

static int
insert_mappable_node(struct drm_i915_private *i915,
		     struct drm_mm_node *node)
{
	return drm_mm_insert_node_in_range_generic(&i915->gtt.base.mm, node,
						   4096, 0, 0,
						   0, i915->gtt.mappable_end,
						   DRM_MM_SEARCH_DEFAULT,
						   DRM_MM_SEARCH_DEFAULT);
}

Should do the trick
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre