[PATCH libdrm] etnaviv: fix BO cache to properly work with different flags

[Philipp Zabel]

On Fri, 2017-12-15 at 11:30 +0100, Lucas Stach wrote:
> Currently if the oldest BO in a bucket has different flags than what we
> look for we'll miss the cache.Fix this by iterating over the cached BOs
> until we find the oldest one with matching flags. This improves the hit
> ratio for some of the buckets.
> 
> Signed-off-by: Lucas Stach <l.stach at pengutronix.de>

Reviewed-by: Philipp Zabel <p.zabel at pengutronix.de>

regards
Philipp

> ---
>  etnaviv/etnaviv_bo_cache.c | 26 +++++++++++++++++++-------
>  1 file changed, 19 insertions(+), 7 deletions(-)
> 
> diff --git a/etnaviv/etnaviv_bo_cache.c b/etnaviv/etnaviv_bo_cache.c
> index 8924651f0cd8..6208230dc81a 100644
> --- a/etnaviv/etnaviv_bo_cache.c
> +++ b/etnaviv/etnaviv_bo_cache.c
> @@ -124,20 +124,32 @@ static int is_idle(struct etna_bo *bo)
>  
>  static struct etna_bo *find_in_bucket(struct etna_bo_bucket *bucket, uint32_t flags)
>  {
> -	struct etna_bo *bo = NULL;
> +	struct etna_bo *bo = NULL, *tmp;
>  
>  	pthread_mutex_lock(&table_lock);
> -	while (!LIST_IS_EMPTY(&bucket->list)) {
> -		bo = LIST_ENTRY(struct etna_bo, bucket->list.next, list);
>  
> -		if (bo->flags == flags && is_idle(bo)) {
> -			list_del(&bo->list);
> -			break;
> +	if (LIST_IS_EMPTY(&bucket->list))
> +		goto out_unlock;
> +
> +	LIST_FOR_EACH_ENTRY_SAFE(bo, tmp, &bucket->list, list) {
> +		/* skip BOs with different flags */
> +		if (bo->flags != flags)
> +			continue;
> +
> +		/* check if the first BO with matching flags is idle */
> +		if (is_idle(bo)) {
> +			list_delinit(&bo->list);
> +			goto out_unlock;
>  		}
>  
> -		bo = NULL;
> +		/* If the oldest BO is still busy, don't try younger ones */
>  		break;
>  	}
> +
> +	/* There was no matching buffer found */
> +	bo = NULL;
> +
> +out_unlock:
>  	pthread_mutex_unlock(&table_lock);
>  
>  	return bo;