drm/i915: Use the async worker to avoid reclaim tainting the ggtt->mutex

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@chris-wilson.co.uk>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200130181710.2030251-3-chris@chris-wilson.co.uk

1 files changed, 6 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/gt/intel_ggtt.c b/drivers/gpu/drm/i915/gt/intel_ggtt.c
index 91ec175c38ec..3b23b431bd56 100644
--- a/drivers/gpu/drm/i915/gt/intel_ggtt.c
+++ b/drivers/gpu/drm/i915/gt/intel_ggtt.c
@@ -106,6 +106,11 @@ static bool needs_idle_maps(struct drm_i915_private *i915)
 
 void i915_ggtt_suspend(struct i915_ggtt *ggtt)
 {
+	struct i915_vma *vma;
+
+	list_for_each_entry(vma, &ggtt->vm.bound_list, vm_link)
+		i915_vma_wait_for_bind(vma);
+
 	ggtt->vm.clear_range(&ggtt->vm, 0, ggtt->vm.total);
 	ggtt->invalidate(ggtt);
 
@@ -841,6 +846,7 @@ static int gen8_gmch_probe(struct i915_ggtt *ggtt)
 	    IS_CHERRYVIEW(i915) /* fails with concurrent use/update */) {
 		ggtt->vm.insert_entries = bxt_vtd_ggtt_insert_entries__BKL;
 		ggtt->vm.insert_page    = bxt_vtd_ggtt_insert_page__BKL;
+		ggtt->vm.bind_async_flags = I915_VMA_GLOBAL_BIND;
 	}
 
 	ggtt->invalidate = gen8_ggtt_invalidate;