1 files changed, 123 insertions, 0 deletions
diff --git a/common/bo-cache.c b/common/bo-cache.c
new file mode 100644
index 0000000..061ab1d
--- /dev/null
+++ b/common/bo-cache.c
@@ -0,0 +1,123 @@
+#include <stdlib.h>
+#include <time.h>
+
+#include "bo-cache.h"
+
+/* The interval in seconds between cache cleans */
+#define BO_CACHE_CLEAN_INTERVAL 1
+/* The maximum age in seconds of a BO in the cache */
+#define BO_CACHE_MAX_AGE	2
+
+/*
+ * These sizes come from the i915 DRM backend - which uses roughly
+ * for n = 2..
+ *   (4096 << n) + (4096 << n) * 1 / 4
+ *   (4096 << n) + (4096 << n) * 2 / 4
+ *   (4096 << n) + (4096 << n) * 3 / 4
+ * The reasoning being that powers of two are too wasteful in X.
+ *
+ * We also add in caches for 720p and 1080p too.
+ */
+static size_t bucket_size[NUM_BUCKETS] = {
+	   4096,	   8192,	  12288,
+	  20480,	  24576,	  28672,
+	  40960,	  49152,	  57344,
+	  81920,	  98304,	 114688,
+	 163840,	 196608,	 229376,
+	 327680,	 393216,	 458752,
+	 655360,	 786432,	 917504,
+	1310720,	1572864,	1835008,
+	2621440,	3145728,	3670016,
+	3686400,	8294400,
+};
+
+void bo_cache_init(struct bo_cache *cache, void (*free)(struct bo_entry *))
+{
+	struct timespec time;
+	unsigned i;
+
+	clock_gettime(CLOCK_MONOTONIC, &time);
+
+	cache->free = free;
+	cache->last_cleaned = time.tv_sec;
+	xorg_list_init(&cache->head);
+
+	for (i = 0; i < NUM_BUCKETS; i++) {
+		xorg_list_init(&cache->buckets[i].head);
+		cache->buckets[i].size = bucket_size[i];
+	}
+}
+
+void bo_cache_fini(struct bo_cache *cache)
+{
+	struct timespec time;
+
+	clock_gettime(CLOCK_MONOTONIC, &time);
+
+	/* Free all entries by winding time forward */
+	bo_cache_clean(cache, time.tv_sec + BO_CACHE_MAX_AGE + 1);
+}
+
+struct bo_bucket *bo_cache_bucket_find(struct bo_cache *cache, size_t size)
+{
+	unsigned i;
+
+	for (i = 0; i < NUM_BUCKETS; i++) {
+		struct bo_bucket *bucket = &cache->buckets[i];
+
+		if (bucket->size >= size)
+			return bucket;
+	}
+
+	return NULL;
+}
+
+struct bo_entry *bo_cache_bucket_get(struct bo_bucket *bucket)
+{
+	struct bo_entry *be = NULL;
+
+	if (!xorg_list_is_empty(&bucket->head)) {
+		be = xorg_list_entry(bucket->head.next, struct bo_entry,
+				     bucket_node);
+
+		xorg_list_del(&be->bucket_node);
+		xorg_list_del(&be->free_node);
+	}
+
+	return be;
+}
+
+void bo_cache_clean(struct bo_cache *cache, time_t time)
+{
+	if (time - cache->last_cleaned < BO_CACHE_CLEAN_INTERVAL)
+		return;
+
+	cache->last_cleaned = time;
+
+	while (!xorg_list_is_empty(&cache->head)) {
+		struct bo_entry *entry;
+
+		entry = xorg_list_first_entry(&cache->head, struct bo_entry,
+					      free_node);
+		if (time - entry->free_time < BO_CACHE_MAX_AGE)
+			break;
+
+		xorg_list_del(&entry->bucket_node);
+		xorg_list_del(&entry->free_node);
+
+		cache->free(entry);
+	}
+}
+
+void bo_cache_put(struct bo_cache *cache, struct bo_entry *entry)
+{
+	struct bo_bucket *bucket = entry->bucket;
+	struct timespec time;
+
+	clock_gettime(CLOCK_MONOTONIC, &time);
+	entry->free_time = time.tv_sec;
+	xorg_list_append(&entry->bucket_node, &bucket->head);
+	xorg_list_append(&entry->free_node, &cache->head);
+
+	bo_cache_clean(cache, time.tv_sec);
+}