[Fix]: Tiny possible issues (#283)

* Fix tiny possible issues

* Add default param string for consistency

Author: haochengxia

libCacheSim/cache/eviction/ARC.c

@@ -222,14 +222,14 @@ static cache_obj_t *ARC_find(cache_t *cache, const request_t *req,
 
   cache_obj_t *obj = cache_find_base(cache, req, update_cache);
 
-  if (!update_cache) {
-    return obj->ARC.ghost ? NULL : obj;
-  }
-
   if (obj == NULL) {
     return NULL;
   }
 
+  if (!update_cache) {
+    return obj->ARC.ghost ? NULL : obj;
+  }
+
   params->curr_obj_in_L1_ghost = false;
   params->curr_obj_in_L2_ghost = false;
 

libCacheSim/cache/eviction/LRUProb.c

@@ -25,6 +25,8 @@ typedef struct LRU_Prob_params {
   int threshold;
 } LRU_Prob_params_t;
 
+static const char *DEFAULT_CACHE_PARAMS = "prob=0.5";
+
 // ***********************************************************************
 // ****                                                               ****
 // ****                   function declarations                       ****
@@ -77,8 +79,10 @@ cache_t *LRU_Prob_init(const common_cache_params_t ccache_params,
   cache->eviction_params =
       (LRU_Prob_params_t *)malloc(sizeof(LRU_Prob_params_t));
   LRU_Prob_params_t *params = (LRU_Prob_params_t *)(cache->eviction_params);
-  params->prob = 0.5;
+  params->q_head = NULL;
+  params->q_tail = NULL;
 
+  LRU_Prob_parse_params(cache, DEFAULT_CACHE_PARAMS);
   if (cache_specific_params != NULL) {
     LRU_Prob_parse_params(cache, cache_specific_params);
   }
@@ -169,6 +173,7 @@ static cache_obj_t *LRU_Prob_find(cache_t *cache, const request_t *req,
  */
 static cache_obj_t *LRU_Prob_insert(cache_t *cache, const request_t *req) {
   LRU_Prob_params_t *params = (LRU_Prob_params_t *)cache->eviction_params;
+
   cache_obj_t *obj = cache_insert_base(cache, req);
   prepend_obj_to_head(&params->q_head, &params->q_tail, obj);
 
@@ -203,6 +208,8 @@ static cache_obj_t *LRU_Prob_to_evict(cache_t *cache, const request_t *req) {
 static void LRU_Prob_evict(cache_t *cache, const request_t *req) {
   LRU_Prob_params_t *params = (LRU_Prob_params_t *)cache->eviction_params;
   cache_obj_t *obj_to_evict = params->q_tail;
+  DEBUG_ASSERT(params->q_tail != NULL);
+
   remove_obj_from_list(&params->q_head, &params->q_tail, obj_to_evict);
   cache_remove_obj_base(cache, obj_to_evict, true);
 }

libCacheSim/cache/eviction/SR_LRU.c

@@ -208,9 +208,13 @@ static cache_obj_t *SR_LRU_find(cache_t *cache, const request_t *req,
     params->C_demoted -= 1;
   }
 
-  if (cache_hit_R || cache_hit_SR) {
+  if (cache_hit_R || (cache_hit_SR && likely(update_cache))) {
+    // if not update_cache obj_SR will not be updated to obj_R
     DEBUG_ASSERT(obj_R != NULL);
     return obj_R;
+  } else if (cache_hit_SR) {
+    // if not update_cache, directly return obj_SR
+    return obj_SR;
   }
   return NULL;
 }