[Intel-gfx] [PATCH 3/3] drm/i915: Use the async worker to avoid reclaim tainting the ggtt->mutex

[Matthew Auld]

On Thu, 30 Jan 2020 at 18:17, Chris Wilson <chris at chris-wilson.co.uk> wrote:
>
> On Braswell and Broxton (also known as Valleyview and Apollolake), we
> need to serialise updates of the GGTT using the big stop_machine()
> hammer. This has the side effect of appearing to lockdep as a possible
> reclaim (since it uses the cpuhp mutex and that is tainted by per-cpu
> allocations). However, we want to use vm->mutex (including ggtt->mutex)
> from within the shrinker and so must avoid such possible taints. For this
> purpose, we introduced the asynchronous vma binding and we can apply it
> to the PIN_GLOBAL so long as take care to add the necessary waits for
> the worker afterwards.
>
> Closes: https://gitlab.freedesktop.org/drm/intel/issues/211
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Reviewed-by: Matthew Auld <matthew.auld at intel.com>