drm/i915: vma/ppgtt lifetime rules
authorMichel Thierry <michel.thierry@intel.com>
Wed, 6 Aug 2014 13:04:44 +0000 (15:04 +0200)
committerDaniel Vetter <daniel.vetter@ffwll.ch>
Tue, 12 Aug 2014 13:22:26 +0000 (15:22 +0200)
commitb9d06dd9d1dd3672b391e6387d62aa8dc4e377bd
tree3d9185f91583b1f061d5744d17d9f6c25f485025
parent14bf993e83e1d6924f4bf4506120a15c4b255e58
drm/i915: vma/ppgtt lifetime rules

VMAs should take a reference of the address space they use.

Now, when the fd is closed, it will release the ref that the context was
holding, but it will still be referenced by any vmas that are still
active.

ppgtt_release() should then only be called when the last thing referencing
it releases the ref, and it can just call the base cleanup and free the
ppgtt.

Note that with this we will extend the lifetime of ppgtts which
contain shared objects. But all the non-shared objects will get
removed as soon as they drop of the active list and for the shared
ones the shrinker can eventually reap them. Since we currently can't
evict ppgtt pagetables either I don't think that temporary leak is
important.

Signed-off-by: Michel Thierry <michel.thierry@intel.com>
[danvet: Add note about potential ppgtt leak with this approach.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
drivers/gpu/drm/i915/i915_drv.h
drivers/gpu/drm/i915/i915_gem.c
drivers/gpu/drm/i915/i915_gem_context.c
drivers/gpu/drm/i915/i915_gem_gtt.c