diff --git a/src/server.c b/src/server.c
index 4fd2f9438..0ef3168fe 100644
--- a/src/server.c
+++ b/src/server.c
@@ -3673,7 +3673,6 @@ int main(int argc, char **argv) {
     spt_init(argc, argv);
 #endif
     setlocale(LC_COLLATE,"");
-    zmalloc_enable_thread_safeness();
     zmalloc_set_oom_handler(redisOutOfMemoryHandler);
     srand(time(NULL)^getpid());
     gettimeofday(&tv,NULL);
diff --git a/src/zmalloc.c b/src/zmalloc.c
index dfcfc01d4..094dd80fa 100644
--- a/src/zmalloc.c
+++ b/src/zmalloc.c
@@ -73,25 +73,16 @@ void zlibc_free(void *ptr) {
 #define update_zmalloc_stat_alloc(__n) do { \
     size_t _n = (__n); \
     if (_n&(sizeof(long)-1)) _n += sizeof(long)-(_n&(sizeof(long)-1)); \
-    if (zmalloc_thread_safe) { \
-        atomicIncr(used_memory,__n); \
-    } else { \
-        used_memory += _n; \
-    } \
+    atomicIncr(used_memory,__n); \
 } while(0)
 
 #define update_zmalloc_stat_free(__n) do { \
     size_t _n = (__n); \
     if (_n&(sizeof(long)-1)) _n += sizeof(long)-(_n&(sizeof(long)-1)); \
-    if (zmalloc_thread_safe) { \
-        atomicDecr(used_memory,__n); \
-    } else { \
-        used_memory -= _n; \
-    } \
+    atomicDecr(used_memory,__n); \
 } while(0)
 
 static size_t used_memory = 0;
-static int zmalloc_thread_safe = 0;
 pthread_mutex_t used_memory_mutex = PTHREAD_MUTEX_INITIALIZER;
 
 static void zmalloc_default_oom(size_t size) {
@@ -220,19 +211,10 @@ char *zstrdup(const char *s) {
 
 size_t zmalloc_used_memory(void) {
     size_t um;
-
-    if (zmalloc_thread_safe) {
-        atomicGet(used_memory,um);
-    } else {
-        um = used_memory;
-    }
+    atomicGet(used_memory,um);
     return um;
 }
 
-void zmalloc_enable_thread_safeness(void) {
-    zmalloc_thread_safe = 1;
-}
-
 void zmalloc_set_oom_handler(void (*oom_handler)(size_t)) {
     zmalloc_oom_handler = oom_handler;
 }
diff --git a/src/zmalloc.h b/src/zmalloc.h
index b6d4e1d97..64f2f36aa 100644
--- a/src/zmalloc.h
+++ b/src/zmalloc.h
@@ -78,7 +78,6 @@ void *zrealloc(void *ptr, size_t size);
 void zfree(void *ptr);
 char *zstrdup(const char *s);
 size_t zmalloc_used_memory(void);
-void zmalloc_enable_thread_safeness(void);
 void zmalloc_set_oom_handler(void (*oom_handler)(size_t));
 float zmalloc_get_fragmentation_ratio(size_t rss);
 size_t zmalloc_get_rss(void);