[PATCH] drm/ttm: enable eviction for Per-VM-BO

[He, Roger]

-----Original Message-----
From: Thomas Hellstrom [mailto:thomas at shipmail.org] 
Sent: Friday, December 15, 2017 2:25 PM
To: He, Roger <Hongbo.He at amd.com>; amd-gfx at lists.freedesktop.org; dri-devel at lists.freedesktop.org
Cc: Koenig, Christian <Christian.Koenig at amd.com>
Subject: Re: [PATCH] drm/ttm: enable eviction for Per-VM-BO

Hi.

On 12/14/2017 09:10 AM, Roger He wrote:
> Change-Id: I0c6ece0decd18d30ccc94e5c7ca106d351941c62
> Signed-off-by: Roger He <Hongbo.He at amd.com>
> ---
>   drivers/gpu/drm/ttm/ttm_bo.c | 11 +++++------
>   1 file changed, 5 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/gpu/drm/ttm/ttm_bo.c 
> b/drivers/gpu/drm/ttm/ttm_bo.c index 098b22e..ba5b486 100644
> --- a/drivers/gpu/drm/ttm/ttm_bo.c
> +++ b/drivers/gpu/drm/ttm/ttm_bo.c
> @@ -707,7 +707,6 @@ 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,
> -			       struct reservation_object *resv,
>   			       uint32_t mem_type,
>   			       const struct ttm_place *place,
>   			       struct ttm_operation_ctx *ctx) @@ -722,8 +721,9 @@ static 
> int ttm_mem_evict_first(struct ttm_bo_device *bdev,
>   	spin_lock(&glob->lru_lock);
>   	for (i = 0; i < TTM_MAX_BO_PRIORITY; ++i) {
>   		list_for_each_entry(bo, &man->lru[i], lru) {
> -			if (bo->resv == resv) {
> -				if (list_empty(&bo->ddestroy))
> +			if (bo->resv == ctx->resv) {
> +				if (!ctx->allow_reserved_eviction &&
> +				    list_empty(&bo->ddestroy))
>   					continue;

	It looks to me like a value of locked==true could leak through from a previous loop iteration here, so that locked ends up to be 	true if (bo->resv == resv  && ctx->allow_reserved_eviction), even if no locking was taking place. Perhaps-re-initialize locked to 	false on each loop iteration?

At  the beginning, I also have this concern about incorrect using of locked. So, add patch a few days ago.

init locked again to prevent incorrect unlock
is it help?


Thanks
Roger(Hongbo.He)

/Thomas

>   			} else {
>   				locked = reservation_object_trylock(bo->resv);
> @@ -835,7 +835,7 @@ 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, bo->resv, mem_type, place, ctx);
> +		ret = ttm_mem_evict_first(bdev, mem_type, place, ctx);
>   		if (unlikely(ret != 0))
>   			return ret;
>   	} while (1);
> @@ -1332,8 +1332,7 @@ 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, NULL, mem_type,
> -						  NULL, &ctx);
> +			ret = ttm_mem_evict_first(bdev, mem_type, NULL, &ctx);
>   			if (ret)
>   				return ret;
>   			spin_lock(&glob->lru_lock);