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Commit 5ac55629 authored by Alex Xie's avatar Alex Xie Committed by Alex Deucher
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drm/amdgpu: Optimize mutex usage (v4) 



In original function amdgpu_bo_list_get, the waiting
for result->lock can be quite long while mutex
bo_list_lock was holding. It can make other tasks
waiting for bo_list_lock for long period.

Secondly, this patch allows several tasks(readers of idr)
to proceed at the same time.

v2: use rcu and kref (Dave Airlie and Christian König)
v3: update v1 commit message (Michel Dänzer)
v4: rebase on upstream (Alex Deucher)

Signed-off-by: default avatarAlex Xie <AlexBin.Xie@amd.com>
Reviewed-by: default avatarChristian König <christian.koenig@amd.com>
parent 99eea4df

drivers/gpu/drm/amd/amdgpu/amdgpu.h

+2 −0
Original line number Original line Diff line number Diff line
@@ -869,6 +869,8 @@ struct amdgpu_fpriv { 




struct amdgpu_bo_list {

struct amdgpu_bo_list {

	struct mutex lock;

	struct mutex lock;

	struct rcu_head rhead;

	struct kref refcount;

	struct amdgpu_bo *gds_obj;

	struct amdgpu_bo *gds_obj;

	struct amdgpu_bo *gws_obj;

	struct amdgpu_bo *gws_obj;

	struct amdgpu_bo *oa_obj;

	struct amdgpu_bo *oa_obj;

drivers/gpu/drm/amd/amdgpu/amdgpu_bo_list.c

+28 −12
Original line number Original line Diff line number Diff line
@@ -41,6 +41,20 @@ static int amdgpu_bo_list_set(struct amdgpu_device *adev, 
				     struct drm_amdgpu_bo_list_entry *info,

				     struct drm_amdgpu_bo_list_entry *info,

				     unsigned num_entries);

				     unsigned num_entries);





static void amdgpu_bo_list_release_rcu(struct kref *ref)

{

	unsigned i;

	struct amdgpu_bo_list *list = container_of(ref, struct amdgpu_bo_list,

						   refcount);



	for (i = 0; i < list->num_entries; ++i)

		amdgpu_bo_unref(&list->array[i].robj);



	mutex_destroy(&list->lock);

	kvfree(list->array);

	kfree_rcu(list, rhead);

}



static int amdgpu_bo_list_create(struct amdgpu_device *adev,

static int amdgpu_bo_list_create(struct amdgpu_device *adev,

				 struct drm_file *filp,

				 struct drm_file *filp,

				 struct drm_amdgpu_bo_list_entry *info,

				 struct drm_amdgpu_bo_list_entry *info,
@@ -57,7 +71,7 @@ static int amdgpu_bo_list_create(struct amdgpu_device *adev, 




	/* initialize bo list*/

	/* initialize bo list*/

	mutex_init(&list->lock);

	mutex_init(&list->lock);



	kref_init(&list->refcount);

	r = amdgpu_bo_list_set(adev, filp, list, info, num_entries);

	r = amdgpu_bo_list_set(adev, filp, list, info, num_entries);

	if (r) {

	if (r) {

		kfree(list);

		kfree(list);
@@ -83,14 +97,9 @@ static void amdgpu_bo_list_destroy(struct amdgpu_fpriv *fpriv, int id) 




	mutex_lock(&fpriv->bo_list_lock);

	mutex_lock(&fpriv->bo_list_lock);

	list = idr_remove(&fpriv->bo_list_handles, id);

	list = idr_remove(&fpriv->bo_list_handles, id);

	if (list) {

		/* Another user may have a reference to this list still */

		mutex_lock(&list->lock);

		mutex_unlock(&list->lock);

		amdgpu_bo_list_free(list);

	}



	mutex_unlock(&fpriv->bo_list_lock);

	mutex_unlock(&fpriv->bo_list_lock);

	if (list)

		kref_put(&list->refcount, amdgpu_bo_list_release_rcu);

}

}





static int amdgpu_bo_list_set(struct amdgpu_device *adev,

static int amdgpu_bo_list_set(struct amdgpu_device *adev,
@@ -185,11 +194,17 @@ amdgpu_bo_list_get(struct amdgpu_fpriv *fpriv, int id) 
{

{

	struct amdgpu_bo_list *result;

	struct amdgpu_bo_list *result;





	mutex_lock(&fpriv->bo_list_lock);

	rcu_read_lock();

	result = idr_find(&fpriv->bo_list_handles, id);

	result = idr_find(&fpriv->bo_list_handles, id);

	if (result)



	if (result) {

		if (kref_get_unless_zero(&result->refcount))

			mutex_lock(&result->lock);

			mutex_lock(&result->lock);

	mutex_unlock(&fpriv->bo_list_lock);

		else

			result = NULL;

	}

	rcu_read_unlock();



	return result;

	return result;

}

}
@@ -227,6 +242,7 @@ void amdgpu_bo_list_get_list(struct amdgpu_bo_list *list, 
void amdgpu_bo_list_put(struct amdgpu_bo_list *list)

void amdgpu_bo_list_put(struct amdgpu_bo_list *list)

{

{

	mutex_unlock(&list->lock);

	mutex_unlock(&list->lock);

	kref_put(&list->refcount, amdgpu_bo_list_release_rcu);

}

}





void amdgpu_bo_list_free(struct amdgpu_bo_list *list)

void amdgpu_bo_list_free(struct amdgpu_bo_list *list)