Commit 99013b10 authored by Chris Wilson's avatar Chris Wilson
Browse files

drm/i915: Make shrink/unshrink be atomic 



Add an atomic counter and always take the spinlock around the pin/unpin
events, so that we can perform the list manipulation concurrently.

Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: default avatarMatthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190910212204.17190-1-chris@chris-wilson.co.uk
parent 85dd14c2

drivers/gpu/drm/i915/gem/i915_gem_domain.c

+2 −1
Original line number Diff line number Diff line
@@ -494,7 +494,8 @@ static void i915_gem_object_bump_inactive_ggtt(struct drm_i915_gem_object *obj) 


		spin_lock_irqsave(&i915->mm.obj_lock, flags);



		if (obj->mm.madv == I915_MADV_WILLNEED)

		if (obj->mm.madv == I915_MADV_WILLNEED &&

		    !atomic_read(&obj->mm.shrink_pin))

			list_move_tail(&obj->mm.link, &i915->mm.shrink_list);



		spin_unlock_irqrestore(&i915->mm.obj_lock, flags);

drivers/gpu/drm/i915/gem/i915_gem_object_types.h

+1 −0
Original line number Diff line number Diff line
@@ -156,6 +156,7 @@ struct drm_i915_gem_object { 
	struct {

		struct mutex lock; /* protects the pages and their use */

		atomic_t pages_pin_count;

		atomic_t shrink_pin;



		struct sg_table *pages;

		void *mapping;

drivers/gpu/drm/i915/gem/i915_gem_pages.c

+1 −0
Original line number Diff line number Diff line
@@ -71,6 +71,7 @@ void __i915_gem_object_set_pages(struct drm_i915_gem_object *obj, 
			list = &i915->mm.shrink_list;

		list_add_tail(&obj->mm.link, list);



		atomic_set(&obj->mm.shrink_pin, 0);

		spin_unlock_irqrestore(&i915->mm.obj_lock, flags);

	}

}

drivers/gpu/drm/i915/gem/i915_gem_shrinker.c

+21 −15
Original line number Diff line number Diff line
@@ -516,46 +516,52 @@ void i915_gem_shrinker_taints_mutex(struct drm_i915_private *i915, 


void i915_gem_object_make_unshrinkable(struct drm_i915_gem_object *obj)

{

	struct drm_i915_private *i915 = obj_to_i915(obj);

	unsigned long flags;



	/*

	 * We can only be called while the pages are pinned or when

	 * the pages are released. If pinned, we should only be called

	 * from a single caller under controlled conditions; and on release

	 * only one caller may release us. Neither the two may cross.

	 */

	if (!list_empty(&obj->mm.link)) { /* pinned by caller */

		struct drm_i915_private *i915 = obj_to_i915(obj);

		unsigned long flags;

	if (atomic_add_unless(&obj->mm.shrink_pin, 1, 0))

		return;



	spin_lock_irqsave(&i915->mm.obj_lock, flags);

		GEM_BUG_ON(list_empty(&obj->mm.link));



	if (!atomic_fetch_inc(&obj->mm.shrink_pin) &&

	    !list_empty(&obj->mm.link)) {

		list_del_init(&obj->mm.link);

		i915->mm.shrink_count--;

		i915->mm.shrink_memory -= obj->base.size;



		spin_unlock_irqrestore(&i915->mm.obj_lock, flags);

	}

	spin_unlock_irqrestore(&i915->mm.obj_lock, flags);

}



static void __i915_gem_object_make_shrinkable(struct drm_i915_gem_object *obj,

					      struct list_head *head)

{

	GEM_BUG_ON(!i915_gem_object_has_pages(obj));

	GEM_BUG_ON(!list_empty(&obj->mm.link));



	if (i915_gem_object_is_shrinkable(obj)) {

	struct drm_i915_private *i915 = obj_to_i915(obj);

	unsigned long flags;



	GEM_BUG_ON(!i915_gem_object_has_pages(obj));

	if (!i915_gem_object_is_shrinkable(obj))

		return;



	if (atomic_add_unless(&obj->mm.shrink_pin, -1, 1))

		return;



	spin_lock_irqsave(&i915->mm.obj_lock, flags);

	GEM_BUG_ON(!kref_read(&obj->base.refcount));

	if (atomic_dec_and_test(&obj->mm.shrink_pin)) {

		GEM_BUG_ON(!list_empty(&obj->mm.link));



		list_add_tail(&obj->mm.link, head);

		i915->mm.shrink_count++;

		i915->mm.shrink_memory += obj->base.size;



		spin_unlock_irqrestore(&i915->mm.obj_lock, flags);

	}

	spin_unlock_irqrestore(&i915->mm.obj_lock, flags);

}



void i915_gem_object_make_shrinkable(struct drm_i915_gem_object *obj)

drivers/gpu/drm/i915/gt/intel_context.c

+1 −1
Original line number Diff line number Diff line
@@ -134,8 +134,8 @@ static int __context_pin_state(struct i915_vma *vma) 


static void __context_unpin_state(struct i915_vma *vma)

{

	__i915_vma_unpin(vma);

	i915_vma_make_shrinkable(vma);

	__i915_vma_unpin(vma);

}



static void __intel_context_retire(struct i915_active *active)

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