Configurable dirty ratio hysteresis

Signed-off-by: Daniel Madej <daniel.madej@huawei.com>

Author: Deixx

inc/cleaning/alru.h

@@ -18,6 +18,7 @@ enum ocf_cleaning_alru_parameters {
 	ocf_alru_flush_max_buffers,
 	ocf_alru_activity_threshold,
 	ocf_alru_dirty_ratio_threshold,
+	ocf_alru_dirty_ratio_inertia,
 };
 
 /**
@@ -87,6 +88,10 @@ enum ocf_cleaning_alru_parameters {
  * when dirty ratio drops below (threshold - inertia).
  */
 
+/** Minimum dirty ratio trigger inertia value */
+#define OCF_ALRU_MIN_DIRTY_RATIO_INERTIA		0
+/** Maximum dirty ratio trigger inertia value */
+#define OCF_ALRU_MAX_DIRTY_RATIO_INERTIA		100
 /** Default dirty ratio trigger inertia value */
 #define OCF_ALRU_DEFAULT_DIRTY_RATIO_INERTIA	5
 /**

src/cleaning/alru.c

@@ -775,6 +775,16 @@ int cleaning_policy_alru_set_cleaning_param(ocf_cache_t cache,
 				"dirty ratio trigger threshold: %d\n",
 				config->dirty_ratio_threshold);
 		break;
+	case ocf_alru_dirty_ratio_inertia:
+		OCF_CLEANING_CHECK_PARAM(cache, param_value,
+				OCF_ALRU_MIN_DIRTY_RATIO_INERTIA,
+				OCF_ALRU_MAX_DIRTY_RATIO_INERTIA,
+				"dirty_ratio_inertia");
+		config->dirty_ratio_inertia = param_value;
+		ocf_cache_log(cache, log_info, "Write-back flush thread "
+				"dirty ratio trigger inertia: %d\n",
+				config->dirty_ratio_inertia);
+		break;
 	default:
 		return -OCF_ERR_INVAL;
 	}
@@ -805,6 +815,9 @@ int cleaning_policy_alru_get_cleaning_param(ocf_cache_t cache,
 	case ocf_alru_dirty_ratio_threshold:
 		*param_value = config->dirty_ratio_threshold;
 		break;
+	case ocf_alru_dirty_ratio_inertia:
+		*param_value = config->dirty_ratio_inertia;
+		break;
 	default:
 		return -OCF_ERR_INVAL;
 	}