[PATCH 2/2] drm/ttm: optimize ttm_mem_evict_first v4

[Chunming Zhou]

On 2017年11月13日 17:54, Christian König wrote:
> Deleted BOs with the same reservation object can be reaped even if they
> can't be reserved.
>
> v2: rebase and we still need to remove/add the BO from/to the LRU.
> v3: fix remove/add one more time, cleanup the logic a bit
> v4: we should still check if the eviction is valuable
>
> Signed-off-by: Christian König <christian.koenig at amd.com>
> ---
>   drivers/gpu/drm/ttm/ttm_bo.c | 54 +++++++++++++++++++++++++++-----------------
>   1 file changed, 33 insertions(+), 21 deletions(-)
>
> diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
> index 691646c0f8d3..7b1525d39ea8 100644
> --- a/drivers/gpu/drm/ttm/ttm_bo.c
> +++ b/drivers/gpu/drm/ttm/ttm_bo.c
> @@ -738,47 +738,57 @@ bool ttm_bo_eviction_valuable(struct ttm_buffer_object *bo,
>   EXPORT_SYMBOL(ttm_bo_eviction_valuable);
>   
>   static int ttm_mem_evict_first(struct ttm_bo_device *bdev,
> -				uint32_t mem_type,
> -				const struct ttm_place *place,
> -				bool interruptible,
> -				bool no_wait_gpu)
> +			       struct reservation_object *resv,
> +			       uint32_t mem_type,
> +			       const struct ttm_place *place,
> +			       bool interruptible,
> +			       bool no_wait_gpu)
>   {
>   	struct ttm_bo_global *glob = bdev->glob;
>   	struct ttm_mem_type_manager *man = &bdev->man[mem_type];
> -	struct ttm_buffer_object *bo;
> -	int ret = -EBUSY;
> +	struct ttm_buffer_object *bo = NULL;
> +	bool locked = false;
>   	unsigned i;
> +	int ret;
>   
>   	spin_lock(&glob->lru_lock);
>   	for (i = 0; i < TTM_MAX_BO_PRIORITY; ++i) {
>   		list_for_each_entry(bo, &man->lru[i], lru) {
> -			ret = reservation_object_trylock(bo->resv) ? 0 : -EBUSY;
> -			if (ret)
> -				continue;
> +			if (bo->resv == resv) {
> +				if (list_empty(&bo->ddestroy))
> +					continue;
Do you have further patches for enabling eviction and swapout for 
allocation?

Regards,
David Zhou
> +
> +			} else {
> +				locked = reservation_object_trylock(bo->resv);
> +				if (!locked)
> +					continue;
> +			}
>   
>   			if (place && !bdev->driver->eviction_valuable(bo,
>   								      place)) {
> -				reservation_object_unlock(bo->resv);
> -				ret = -EBUSY;
> +				if (locked)
> +					reservation_object_unlock(bo->resv);
>   				continue;
>   			}
> -
>   			break;
>   		}
>   
> -		if (!ret)
> +		if (&bo->lru != &man->lru[i])
>   			break;
> +		else
> +			bo = NULL;
>   	}
>   
> -	if (ret) {
> +	if (!bo) {
>   		spin_unlock(&glob->lru_lock);
> -		return ret;
> +		return -EBUSY;
>   	}
>   
>   	kref_get(&bo->list_kref);
>   
>   	if (!list_empty(&bo->ddestroy)) {
> -		ret = ttm_bo_cleanup_refs(bo, interruptible, no_wait_gpu, true);
> +		ret = ttm_bo_cleanup_refs(bo, interruptible, no_wait_gpu,
> +					  locked);
>   		kref_put(&bo->list_kref, ttm_bo_release_list);
>   		return ret;
>   	}
> @@ -786,10 +796,11 @@ static int ttm_mem_evict_first(struct ttm_bo_device *bdev,
>   	ttm_bo_del_from_lru(bo);
>   	spin_unlock(&glob->lru_lock);
>   
> -	BUG_ON(ret != 0);
> -
>   	ret = ttm_bo_evict(bo, interruptible, no_wait_gpu);
> -	ttm_bo_unreserve(bo);
> +	if (locked)
> +		ttm_bo_unreserve(bo);
> +	else
> +		ttm_bo_add_to_lru(bo);
>   
>   	kref_put(&bo->list_kref, ttm_bo_release_list);
>   	return ret;
> @@ -853,7 +864,7 @@ static int ttm_bo_mem_force_space(struct ttm_buffer_object *bo,
>   			return ret;
>   		if (mem->mm_node)
>   			break;
> -		ret = ttm_mem_evict_first(bdev, mem_type, place,
> +		ret = ttm_mem_evict_first(bdev, bo->resv, mem_type, place,
>   					  interruptible, no_wait_gpu);
>   		if (unlikely(ret != 0))
>   			return ret;
> @@ -1356,7 +1367,8 @@ static int ttm_bo_force_list_clean(struct ttm_bo_device *bdev,
>   	for (i = 0; i < TTM_MAX_BO_PRIORITY; ++i) {
>   		while (!list_empty(&man->lru[i])) {
>   			spin_unlock(&glob->lru_lock);
> -			ret = ttm_mem_evict_first(bdev, mem_type, NULL, false, false);
> +			ret = ttm_mem_evict_first(bdev, NULL, mem_type, NULL,
> +						  false, false);
>   			if (ret)
>   				return ret;
>   			spin_lock(&glob->lru_lock);