[PATCH v4 1/3] drm/i915/gem: Implement object migration

[Matthew Auld]

On Tue, 29 Jun 2021 at 12:37, Thomas Hellström
<thomas.hellstrom at linux.intel.com> wrote:
>
> Introduce an interface to migrate objects between regions.
> This is primarily intended to migrate objects to LMEM for display and
> to SYSTEM for dma-buf, but might be reused in one form or another for
> performance-based migration.
>
> v2:
> - Verify that the memory region given as an id really exists.
>   (Reported by Matthew Auld)
> - Call i915_gem_object_{init,release}_memory_region() when switching region
>   to handle also switching region lists. (Reported by Matthew Auld)
> v3:
> - Fix i915_gem_object_can_migrate() to return true if object is already in
>   the correct region, even if the object ops doesn't have a migrate()
>   callback.
> - Update typo in commit message.
> - Fix kerneldoc of i915_gem_object_wait_migration().
> v4:
> - Improve documentation (Suggested by Mattew Auld and Michael Ruhl)
> - Always assume TTM migration hits a TTM move and unsets the pages through
>   move_notify. (Reported by Matthew Auld)
> - Add a dma_fence_might_wait() annotation to
>   i915_gem_object_wait_migration() (Suggested by Daniel Vetter)
>
> Reported-by: kernel test robot <lkp at intel.com>
> Signed-off-by: Thomas Hellström <thomas.hellstrom at linux.intel.com>
> Reviewed-by: Michael J. Ruhl <michael.j.ruhl at intel.com>
Reviewed-by: Matthew Auld <matthew.auld at intel.com>