[Intel-gfx] [PATCH 02/18] drm/i915: introduce drm_i915_gem_object page_size members

[Chris Wilson]

On Wed, Apr 05, 2017 at 08:49:17AM +0200, Daniel Vetter wrote:
> On Tue, Apr 04, 2017 at 11:11:12PM +0100, Matthew Auld wrote:
> > Signed-off-by: Matthew Auld <matthew.auld at intel.com>
> > ---
> >  drivers/gpu/drm/i915/i915_gem.c        | 5 +++++
> >  drivers/gpu/drm/i915/i915_gem_object.h | 3 +++
> >  2 files changed, 8 insertions(+)
> > 
> > diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
> > index 4ca88f2539c0..cbf97f4bbb72 100644
> > --- a/drivers/gpu/drm/i915/i915_gem.c
> > +++ b/drivers/gpu/drm/i915/i915_gem.c
> > @@ -2441,6 +2441,8 @@ static int ____i915_gem_object_get_pages(struct drm_i915_gem_object *obj)
> >  	struct sg_table *pages;
> >  
> >  	GEM_BUG_ON(i915_gem_object_has_pinned_pages(obj));
> > +	GEM_BUG_ON(!is_valid_gtt_page_size(obj->page_size));
> > +	GEM_BUG_ON(!is_valid_gtt_page_size(obj->gtt_page_size));
> >  
> >  	if (unlikely(obj->mm.madv != I915_MADV_WILLNEED)) {
> >  		DRM_DEBUG("Attempting to obtain a purgeable object\n");
> > @@ -4159,6 +4161,9 @@ void i915_gem_object_init(struct drm_i915_gem_object *obj,
> >  
> >  	obj->ops = ops;
> >  
> > +	obj->page_size = PAGE_SIZE;
> > +	obj->gtt_page_size = I915_GTT_PAGE_SIZE;
> > +
> >  	reservation_object_init(&obj->__builtin_resv);
> >  	obj->resv = &obj->__builtin_resv;
> >  
> > diff --git a/drivers/gpu/drm/i915/i915_gem_object.h b/drivers/gpu/drm/i915/i915_gem_object.h
> > index 174cf923c236..b1dacbfe5173 100644
> > --- a/drivers/gpu/drm/i915/i915_gem_object.h
> > +++ b/drivers/gpu/drm/i915/i915_gem_object.h
> > @@ -107,6 +107,9 @@ struct drm_i915_gem_object {
> >  	unsigned int cache_level:3;
> >  	unsigned int cache_dirty:1;
> >  
> > +	unsigned int page_size; /* CPU pov - 4K(default), 2M, 1G */
> > +	unsigned int gtt_page_size; /* GPU pov - 4K(default), 64K, 2M, 1G */
> 
> Just kinda archecture review, with a long-term view: Is the plan to
> eventually become more flexible here, i.e. allow mixed mode?

Simply put we can not support obj->page_size. Every object will be
composed of a mixture of page sizes, often outside of our control and
those page sizes may vary over the lifetime of the object.

Trying to design around an a priori static page_size is a bad idea, imo.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre