[PATCH 3/5] drm/ttm: add ttm_bo_move_to_lru_tail function v2

[Thomas Hellstrom]

LGTM,

Although perhaps check that the LRU lock is held as well.

Reviewed-by: Thomas Hellstrom <thellstrom at vmware.com>

On 01/11/2016 03:35 PM, Christian König wrote:
> From: Christian König <christian.koenig at amd.com>
>
> This allows the drivers to move a BO to the end of the LRU
> without removing and adding it again.
>
> v2: Make it more robust, handle pinned and swapable BOs as well.
>
> Signed-off-by: Christian König <christian.koenig at amd.com>
> ---
>  drivers/gpu/drm/ttm/ttm_bo.c | 21 +++++++++++++++++++++
>  include/drm/ttm/ttm_bo_api.h | 10 ++++++++++
>  2 files changed, 31 insertions(+)
>
> diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
> index 3ea9a01..4cbf265 100644
> --- a/drivers/gpu/drm/ttm/ttm_bo.c
> +++ b/drivers/gpu/drm/ttm/ttm_bo.c
> @@ -228,6 +228,27 @@ void ttm_bo_del_sub_from_lru(struct ttm_buffer_object *bo)
>  }
>  EXPORT_SYMBOL(ttm_bo_del_sub_from_lru);
>  
> +void ttm_bo_move_to_lru_tail(struct ttm_buffer_object *bo)
> +{
> +	struct ttm_bo_device *bdev = bo->bdev;
> +	struct ttm_mem_type_manager *man;
> +
> +	lockdep_assert_held(&bo->resv->lock.base);
> +
> +	if (bo->mem.placement & TTM_PL_FLAG_NO_EVICT) {
> +		list_del_init(&bo->swap);
> +		list_del_init(&bo->lru);
> +
> +	} else {
> +		if (bo->ttm && !(bo->ttm->page_flags & TTM_PAGE_FLAG_SG))
> +			list_move_tail(&bo->swap, &bo->glob->swap_lru);
> +
> +		man = &bdev->man[bo->mem.mem_type];
> +		list_move_tail(&bo->lru, &man->lru);
> +	}
> +}
> +EXPORT_SYMBOL(ttm_bo_move_to_lru_tail);
> +
>  /*
>   * Call bo->mutex locked.
>   */
> diff --git a/include/drm/ttm/ttm_bo_api.h b/include/drm/ttm/ttm_bo_api.h
> index c768ddf..afae231 100644
> --- a/include/drm/ttm/ttm_bo_api.h
> +++ b/include/drm/ttm/ttm_bo_api.h
> @@ -383,6 +383,16 @@ extern void ttm_bo_add_to_lru(struct ttm_buffer_object *bo);
>   */
>  extern int ttm_bo_del_from_lru(struct ttm_buffer_object *bo);
>  
> +/**
> + * ttm_bo_move_to_lru_tail
> + *
> + * @bo: The buffer object.
> + *
> + * Move this BO to the tail of all lru lists used to lookup and reserve an
> + * object. This function must be called with struct ttm_bo_global::lru_lock
> + * held, and is used to make a BO less likely to be considered for eviction.
> + */
> +extern void ttm_bo_move_to_lru_tail(struct ttm_buffer_object *bo);
>  
>  /**
>   * ttm_bo_lock_delayed_workqueue