[Intel-gfx] [PATCH 3/5] drm/i915: Add support for stealing purgable stolen pages

[Chris Wilson]

On Wed, Sep 23, 2015 at 04:21:21PM +0530, ankitprasad.r.sharma at intel.com wrote:
> From: Chris Wilson <chris at chris-wilson.co.uk>
> 
> If we run out of stolen memory when trying to allocate an object, see if
> we can reap enough purgeable objects to free up enough contiguous free
> space for the allocation. This is in principle very much like evicting
> objects to free up enough contiguous space in the vma when binding
> a new object - and you will be forgiven for thinking that the code looks
> very similar.
> 
> At the moment, we do not allow userspace to allocate objects in stolen,
> so there is neither the memory pressure to trigger stolen eviction nor
> any purgeable objects inside the stolen arena. However, this will change
> in the near future, and so better management and defragmentation of
> stolen memory will become a real issue.
> 
> v2: Remember to remove the drm_mm_node.
> 
> v3: Rebased to the latest drm-intel-nightly (Ankit)
> 
> v4: corrected if-else braces format (Tvrtko/kerneldoc)
> 
> v5: Rebased to the latest drm-intel-nightly (Ankit)
> Added a seperate list to maintain purgable objects from stolen memory
> region (Chris/Daniel)
> 
> v6: Compiler optimization (merging 2 single loops into one for() loop),
> corrected code for object eviction, retire_requests before starting
> object eviction (Chris)
> 
> Testcase: igt/gem_stolen
> 
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> Signed-off-by: Ankitprasad Sharma <ankitprasad.r.sharma at intel.com>

I could not find anything to complain about.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre