Re: [PATCH 2/2] drm/i915: use drm_mm_remove_node instead of put_block

[Ben Widawsky <ben@bwidawsk.net>]

On Mon, Jul 01, 2013 at 10:39:03PM +0200, Daniel Vetter wrote:
> On Mon, Jul 01, 2013 at 10:21:57PM +0200, David Herrmann wrote:
> > Hi
> > 
> > On Mon, Jul 1, 2013 at 10:05 PM, Daniel Vetter <daniel.vetter@ffwll.ch> wrote:
> > > When converting to the preallocated drm_mm_node interfaces in
> > >
> > > commit dc9dd7a20fde95aa81a8307cde79c2dff9f83f3d
> > > Author: Chris Wilson <chris@chris-wilson.co.uk>
> > > Date:   Fri Dec 7 20:37:07 2012 +0000
> > >
> > >     drm/i915: Preallocate the drm_mm_node prior to manipulating the GTT drm_mm
> > >
> > > only the allocation side was converted, but not the freeing. Fix this
> > > up.
> > >
> > > Note that the only difference between put_block and remove_node is
> > > that the former fills up the preallocation cache. Which we don't need
> > > anyway and hence is just wasted space.
> > >
> > > Cc: Chris Wilson <chris@chris-wilson.co.uk>
> > > Cc: Ben Widawsky <ben@bwidawsk.net>
> > > Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
> > > ---
> > >  drivers/gpu/drm/i915/i915_gem.c | 6 +++---
> > >  1 file changed, 3 insertions(+), 3 deletions(-)
> > >
> > > diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
> > > index 4200c32..30fd694 100644
> > > --- a/drivers/gpu/drm/i915/i915_gem.c
> > > +++ b/drivers/gpu/drm/i915/i915_gem.c
> > > @@ -2620,7 +2620,7 @@ i915_gem_object_unbind(struct drm_i915_gem_object *obj)
> > >         /* Avoid an unnecessary call to unbind on rebind. */
> > >         obj->map_and_fenceable = true;
> > >
> > > -       drm_mm_put_block(obj->gtt_space);
> > > +       drm_mm_remove_node(obj->gtt_space);
> > 
> > kfree(obj->gtt_space);
> > 
> > >         obj->gtt_space = NULL;
> > >         obj->gtt_offset = 0;
> > >
> > > @@ -3137,14 +3137,14 @@ search_free:
> > >         }
> > >         if (WARN_ON(!i915_gem_valid_gtt_space(dev, node, obj->cache_level))) {
> > >                 i915_gem_object_unpin_pages(obj);
> > > -               drm_mm_put_block(node);
> > > +               drm_mm_remove_node(node);
> > 
> > kfree(node);
> > 
> > >                 return -EINVAL;
> > >         }
> > >
> > >         ret = i915_gem_gtt_prepare_object(obj);
> > >         if (ret) {
> > >                 i915_gem_object_unpin_pages(obj);
> > > -               drm_mm_put_block(node);
> > > +               drm_mm_remove_node(node);
> > 
> > kfree(node);
> 
> Yeah, I fail ...
> 
> > drm_mm_remove_node() does unlink the node but not remove it. Btw., I
> > have these fixes in my series, too. I will push it later and write the
> > git-link to #dri-devel.
> 
> We have patches in-flight to convert over to embedded drm_mm_nodes anyway,
> so I guess that part will solve itself automatically.
> -Daniel

I'm planning to get this out ASAP. I'm a bit confused now though what I
actually need to send.

-- 
Ben Widawsky, Intel Open Source Technology Center