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

[Lucas Stach]

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>
---
 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;
-- 
2.11.0