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Commit cc731f5a authored by Chris Wilson's avatar Chris Wilson
Browse files

drm/i915: Trim struct_mutex hold duration for i915_gem_free_objects 



We free objects in bulk after they wait for their RCU grace period.
Currently, we take struct_mutex and unbind all the objects. This can lead
to a long lock duration during which time those objects have their pages
unfreeable (i.e. the shrinker is prevented from reaping those pages). If
we only process a single object under the struct_mutex and then free the
pages, the number of objects locked away from the shrinker is minimal
and we allow regular clients better access to struct_mutex if they need
it.

Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: default avatarJoonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171013202621.7276-9-chris@chris-wilson.co.uk
parent 87701b4b

drivers/gpu/drm/i915/i915_gem.c

+8 −8
Original line number Diff line number Diff line
@@ -4490,13 +4490,14 @@ static void __i915_gem_free_objects(struct drm_i915_private *i915, 
{

	struct drm_i915_gem_object *obj, *on;



	mutex_lock(&i915->drm.struct_mutex);

	intel_runtime_pm_get(i915);

	llist_for_each_entry(obj, freed, freed) {

	llist_for_each_entry_safe(obj, on, freed, freed) {

		struct i915_vma *vma, *vn;



		trace_i915_gem_object_destroy(obj);



		mutex_lock(&i915->drm.struct_mutex);



		GEM_BUG_ON(i915_gem_object_is_active(obj));

		list_for_each_entry_safe(vma, vn,

					 &obj->vma_list, obj_link) {
@@ -4519,13 +4520,8 @@ static void __i915_gem_free_objects(struct drm_i915_private *i915, 
			spin_unlock(&i915->mm.obj_lock);

		}



	}

	intel_runtime_pm_put(i915);

		mutex_unlock(&i915->drm.struct_mutex);



	cond_resched();



	llist_for_each_entry_safe(obj, on, freed, freed) {

		GEM_BUG_ON(obj->bind_count);

		GEM_BUG_ON(obj->userfault_count);

		GEM_BUG_ON(atomic_read(&obj->frontbuffer_bits));
@@ -4548,7 +4544,11 @@ static void __i915_gem_free_objects(struct drm_i915_private *i915, 


		kfree(obj->bit_17);

		i915_gem_object_free(obj);



		if (on)

			cond_resched();

	}

	intel_runtime_pm_put(i915);

}



static void i915_gem_flush_free_objects(struct drm_i915_private *i915)