Add promotion policy API and use it in I/O path

Promotion policy is supposed to perform ALRU noise filtering by
eliminating one-hit wonders being added to cache and polluting it.

Signed-off-by: Jan Musial <jan.musial@intel.com>

inc/ocf_def.h

@@ -193,7 +193,7 @@ typedef enum {
 } ocf_seq_cutoff_policy;
 
 /**
- * OCF supported eviction types
+ * OCF supported eviction policy types
  */
 typedef enum {
 	ocf_eviction_lru = 0,
@@ -206,6 +206,23 @@ typedef enum {
 		/*!< Default eviction policy */
 } ocf_eviction_t;
 
+/**
+ * OCF supported promotion policy types
+ */
+typedef enum {
+	ocf_promotion_nop = 0,
+		/*!< No promotion policy. Cache inserts are not filtered */
+
+	ocf_promotion_nhit,
+		/*!< Line can be inserted after N requests for it */
+
+	ocf_promotion_max,
+		/*!< Stopper of enumerator */
+
+	ocf_promotion_default = ocf_promotion_nop,
+		/*!< Default promotion policy */
+} ocf_promotion_t;
+
 /**
  * OCF supported Write-Back cleaning policies type
  */

inc/ocf_mngt.h

@@ -262,6 +262,11 @@ struct ocf_mngt_cache_config {
 	 */
 	ocf_eviction_t eviction_policy;
 
+	/**
+	 * @brief Promotion policy type
+	 */
+	ocf_promotion_t promotion_policy;
+
 	/**
 	 * @brief Cache line size
 	 */
@@ -313,6 +318,7 @@ static inline void ocf_mngt_cache_config_set_default(
 	cfg->name = NULL;
 	cfg->cache_mode = ocf_cache_mode_default;
 	cfg->eviction_policy = ocf_eviction_default;
+	cfg->promotion_policy = ocf_promotion_default;
 	cfg->cache_line_size = ocf_cache_line_size_4;
 	cfg->metadata_layout = ocf_metadata_layout_default;
 	cfg->metadata_volatile = false;