diff --git a/inc/ocf_def.h b/inc/ocf_def.h
index b5a4364..bdbe211 100644
--- a/inc/ocf_def.h
+++ b/inc/ocf_def.h
@@ -352,6 +352,6 @@ typedef enum {
  * @}
  */
 
-#define MAX_TRIM_RQ_SIZE	(1 * MiB)
+#define MAX_TRIM_RQ_SIZE	(512 * KiB)
 
 #endif /* __OCF_DEF_H__ */
diff --git a/src/ocf_request.c b/src/ocf_request.c
index 8584b71..be98f0a 100644
--- a/src/ocf_request.c
+++ b/src/ocf_request.c
@@ -224,6 +224,9 @@ int ocf_req_alloc_map(struct ocf_request *req)
 
 int ocf_req_alloc_map_discard(struct ocf_request *req)
 {
+	ENV_BUILD_BUG_ON(MAX_TRIM_RQ_SIZE / ocf_cache_line_size_4 *
+			sizeof(struct ocf_map_info) > 4 * KiB);
+
 	if (req->byte_length <= MAX_TRIM_RQ_SIZE)
 		return ocf_req_alloc_map(req);