[PATCH] drm/mm: Fix search for smallest hole satisfying constraints

[Michel Dänzer]

On Mit, 2014-03-19 at 11:38 +0100, Daniel Vetter wrote:
> On Wed, Mar 19, 2014 at 05:42:27PM +0900, Michel Dänzer wrote:
> > On Die, 2014-03-18 at 11:01 +0100, Daniel Vetter wrote:
> > > On Tue, Mar 18, 2014 at 09:58:14AM +0900, Michel Dänzer wrote:
> > > > From: Michel Dänzer <michel.daenzer at amd.com>
> > > > 
> > > > entry->size is the size of the node, not the size of the hole after it.
> > > > So the code would actually find the hole which can satisfy the
> > > > constraints and which is preceded by the smallest node, not the smallest
> > > > hole satisfying the constraints.
> > > > 
> > > > Reported-by: "Huang, FrankR" <FrankR.Huang at amd.com>
> > > > Signed-off-by: Michel Dänzer <michel.daenzer at amd.com>
> > > 
> > > But drm-next just gained my kerneldoc patch for drm_mm, so can you please
> > > respin your patch and update the docs too?
> > 
> > What kind of update are you thinking of?
> 
> you've changed the function parameters, which breaks the kerneldoc. v2 is
> ok in that regard.

Ah, I see.


> > Meanwhile, I've submitted a less invasive v2 fix.
> 
> Reviewed-by: Daniel Vetter <daniel.vetter at ffwll.ch> on that one.

Merci! :)


> > BTW, do you think the fix would interact properly with coloring?
> 
> Coloring only adjusts start/end so won't affect the size of the hole. If
> you really see benefits from best_match

I've been wondering about the potential effects of this fix... I hope it
won't cause regressions.

> then I guess you could look into pessimising holes which need to be
> split, presuming radeon has a pile of alignment or otherwise
> constrained buffers.

E.g. textures with 2D tiling can require pretty large alignment, so that
might indeed be interesting.


-- 
Earthling Michel Dänzer            |                  http://www.amd.com
Libre software enthusiast          |                Mesa and X developer