Commit e2ccc50a authored by Chris Wilson's avatar Chris Wilson
Browse files

drm/i915: Track ggtt fence reservations under its own mutex 



We can reduce the locking for fence registers from the dev->struct_mutex
to a local mutex. We could introduce a mutex for the sole purpose of
tracking the fence acquisition, except there is a little bit of overlap
with the fault tracking, so use the i915_ggtt.mutex as it covers both.

Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: default avatarMatthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190822060914.2671-1-chris@chris-wilson.co.uk
parent 8e458fe2

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

+7 −0
Original line number Diff line number Diff line
@@ -1157,7 +1157,14 @@ static int evict_fence(void *data) 
		goto out_unlock;

	}



	err = i915_vma_pin(arg->vma, 0, 0, PIN_GLOBAL | PIN_MAPPABLE);

	if (err) {

		pr_err("Unable to pin vma for Y-tiled fence; err:%d\n", err);

		goto out_unlock;

	}



	err = i915_vma_pin_fence(arg->vma);

	i915_vma_unpin(arg->vma);

	if (err) {

		pr_err("Unable to pin Y-tiled fence; err:%d\n", err);

		goto out_unlock;

drivers/gpu/drm/i915/gvt/aperture_gm.c

+5 −5
Original line number Diff line number Diff line
@@ -172,14 +172,14 @@ static void free_vgpu_fence(struct intel_vgpu *vgpu) 


	intel_runtime_pm_get(&dev_priv->runtime_pm);



	mutex_lock(&dev_priv->drm.struct_mutex);

	mutex_lock(&dev_priv->ggtt.vm.mutex);

	_clear_vgpu_fence(vgpu);

	for (i = 0; i < vgpu_fence_sz(vgpu); i++) {

		reg = vgpu->fence.regs[i];

		i915_unreserve_fence(reg);

		vgpu->fence.regs[i] = NULL;

	}

	mutex_unlock(&dev_priv->drm.struct_mutex);

	mutex_unlock(&dev_priv->ggtt.vm.mutex);



	intel_runtime_pm_put_unchecked(&dev_priv->runtime_pm);

}
@@ -195,7 +195,7 @@ static int alloc_vgpu_fence(struct intel_vgpu *vgpu) 
	intel_runtime_pm_get(rpm);



	/* Request fences from host */

	mutex_lock(&dev_priv->drm.struct_mutex);

	mutex_lock(&dev_priv->ggtt.vm.mutex);



	for (i = 0; i < vgpu_fence_sz(vgpu); i++) {

		reg = i915_reserve_fence(dev_priv);
@@ -207,7 +207,7 @@ static int alloc_vgpu_fence(struct intel_vgpu *vgpu) 


	_clear_vgpu_fence(vgpu);



	mutex_unlock(&dev_priv->drm.struct_mutex);

	mutex_unlock(&dev_priv->ggtt.vm.mutex);

	intel_runtime_pm_put_unchecked(rpm);

	return 0;

out_free_fence:
@@ -220,7 +220,7 @@ out_free_fence: 
		i915_unreserve_fence(reg);

		vgpu->fence.regs[i] = NULL;

	}

	mutex_unlock(&dev_priv->drm.struct_mutex);

	mutex_unlock(&dev_priv->ggtt.vm.mutex);

	intel_runtime_pm_put_unchecked(rpm);

	return -ENOSPC;

}

drivers/gpu/drm/i915/i915_debugfs.c

+3 −2
Original line number Diff line number Diff line
@@ -652,10 +652,11 @@ static int i915_gem_fence_regs_info(struct seq_file *m, void *data) 


	rcu_read_lock();

	for (i = 0; i < i915->ggtt.num_fences; i++) {

		struct i915_vma *vma = i915->ggtt.fence_regs[i].vma;

		struct i915_fence_reg *reg = &i915->ggtt.fence_regs[i];

		struct i915_vma *vma = reg->vma;



		seq_printf(m, "Fence %d, pin count = %d, object = ",

			   i, i915->ggtt.fence_regs[i].pin_count);

			   i, atomic_read(&reg->pin_count));

		if (!vma)

			seq_puts(m, "unused");

		else

drivers/gpu/drm/i915/i915_gem_fence_reg.c

+69 −39
Original line number Diff line number Diff line
@@ -299,15 +299,24 @@ static int fence_update(struct i915_fence_reg *fence, 
 */

int i915_vma_put_fence(struct i915_vma *vma)

{

	struct i915_ggtt *ggtt = i915_vm_to_ggtt(vma->vm);

	struct i915_fence_reg *fence = vma->fence;

	int err;



	if (!fence)

		return 0;



	if (fence->pin_count)

	if (atomic_read(&fence->pin_count))

		return -EBUSY;



	return fence_update(fence, NULL);

	err = mutex_lock_interruptible(&ggtt->vm.mutex);

	if (err)

		return err;



	err = fence_update(fence, NULL);

	mutex_unlock(&ggtt->vm.mutex);



	return err;

}



static struct i915_fence_reg *fence_find(struct drm_i915_private *i915)
@@ -317,7 +326,7 @@ static struct i915_fence_reg *fence_find(struct drm_i915_private *i915) 
	list_for_each_entry(fence, &i915->ggtt.fence_list, link) {

		GEM_BUG_ON(fence->vma && fence->vma->fence != fence);



		if (fence->pin_count)

		if (atomic_read(&fence->pin_count))

			continue;



		return fence;
@@ -330,6 +339,48 @@ static struct i915_fence_reg *fence_find(struct drm_i915_private *i915) 
	return ERR_PTR(-EDEADLK);

}



static int __i915_vma_pin_fence(struct i915_vma *vma)

{

	struct i915_ggtt *ggtt = i915_vm_to_ggtt(vma->vm);

	struct i915_fence_reg *fence;

	struct i915_vma *set = i915_gem_object_is_tiled(vma->obj) ? vma : NULL;

	int err;



	/* Just update our place in the LRU if our fence is getting reused. */

	if (vma->fence) {

		fence = vma->fence;

		GEM_BUG_ON(fence->vma != vma);

		atomic_inc(&fence->pin_count);

		if (!fence->dirty) {

			list_move_tail(&fence->link, &ggtt->fence_list);

			return 0;

		}

	} else if (set) {

		fence = fence_find(vma->vm->i915);

		if (IS_ERR(fence))

			return PTR_ERR(fence);



		GEM_BUG_ON(atomic_read(&fence->pin_count));

		atomic_inc(&fence->pin_count);

	} else {

		return 0;

	}



	err = fence_update(fence, set);

	if (err)

		goto out_unpin;



	GEM_BUG_ON(fence->vma != set);

	GEM_BUG_ON(vma->fence != (set ? fence : NULL));



	if (set)

		return 0;



out_unpin:

	atomic_dec(&fence->pin_count);

	return err;

}



/**

 * i915_vma_pin_fence - set up fencing for a vma

 * @vma: vma to map through a fence reg
@@ -350,8 +401,6 @@ static struct i915_fence_reg *fence_find(struct drm_i915_private *i915) 
 */

int i915_vma_pin_fence(struct i915_vma *vma)

{

	struct i915_fence_reg *fence;

	struct i915_vma *set = i915_gem_object_is_tiled(vma->obj) ? vma : NULL;

	int err;



	/*
@@ -359,39 +408,16 @@ int i915_vma_pin_fence(struct i915_vma *vma) 
	 * must keep the device awake whilst using the fence.

	 */

	assert_rpm_wakelock_held(&vma->vm->i915->runtime_pm);

	GEM_BUG_ON(!i915_vma_is_pinned(vma));

	GEM_BUG_ON(!i915_vma_is_ggtt(vma));



	/* Just update our place in the LRU if our fence is getting reused. */

	if (vma->fence) {

		fence = vma->fence;

		GEM_BUG_ON(fence->vma != vma);

		fence->pin_count++;

		if (!fence->dirty) {

			list_move_tail(&fence->link,

				       &fence->i915->ggtt.fence_list);

			return 0;

		}

	} else if (set) {

		fence = fence_find(vma->vm->i915);

		if (IS_ERR(fence))

			return PTR_ERR(fence);



		GEM_BUG_ON(fence->pin_count);

		fence->pin_count++;

	} else

		return 0;



	err = fence_update(fence, set);

	err = mutex_lock_interruptible(&vma->vm->mutex);

	if (err)

		goto out_unpin;



	GEM_BUG_ON(fence->vma != set);

	GEM_BUG_ON(vma->fence != (set ? fence : NULL));

		return err;



	if (set)

		return 0;

	err = __i915_vma_pin_fence(vma);

	mutex_unlock(&vma->vm->mutex);



out_unpin:

	fence->pin_count--;

	return err;

}
@@ -404,16 +430,17 @@ out_unpin: 
 */

struct i915_fence_reg *i915_reserve_fence(struct drm_i915_private *i915)

{

	struct i915_ggtt *ggtt = &i915->ggtt;

	struct i915_fence_reg *fence;

	int count;

	int ret;



	lockdep_assert_held(&i915->drm.struct_mutex);

	lockdep_assert_held(&ggtt->vm.mutex);



	/* Keep at least one fence available for the display engine. */

	count = 0;

	list_for_each_entry(fence, &i915->ggtt.fence_list, link)

		count += !fence->pin_count;

	list_for_each_entry(fence, &ggtt->fence_list, link)

		count += !atomic_read(&fence->pin_count);

	if (count <= 1)

		return ERR_PTR(-ENOSPC);
@@ -429,6 +456,7 @@ struct i915_fence_reg *i915_reserve_fence(struct drm_i915_private *i915) 
	}



	list_del(&fence->link);



	return fence;

}
@@ -440,9 +468,11 @@ struct i915_fence_reg *i915_reserve_fence(struct drm_i915_private *i915) 
 */

void i915_unreserve_fence(struct i915_fence_reg *fence)

{

	lockdep_assert_held(&fence->i915->drm.struct_mutex);

	struct i915_ggtt *ggtt = &fence->i915->ggtt;



	lockdep_assert_held(&ggtt->vm.mutex);



	list_add(&fence->link, &fence->i915->ggtt.fence_list);

	list_add(&fence->link, &ggtt->fence_list);

}



/**

drivers/gpu/drm/i915/i915_gem_fence_reg.h

+1 −1
Original line number Diff line number Diff line
@@ -41,7 +41,7 @@ struct i915_fence_reg { 
	struct list_head link;

	struct drm_i915_private *i915;

	struct i915_vma *vma;

	int pin_count;

	atomic_t pin_count;

	int id;

	/**

	 * Whether the tiling parameters for the currently

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