diff --git a/m-buffer.h b/m-buffer.h
index 81e4f406..1d6578cf 100644
--- a/m-buffer.h
+++ b/m-buffer.h
@@ -285,9 +285,14 @@ M_C(name, _init)(buffer_t v, size_t size)                               \
    }                                                                    \
                                                                         \
    /* Increment number of elements of the buffer */                     \
-   atomic_store (&v->number[0], atomic_load(&v->number[0]) + 1);        \
-   if (BUFFERI_POLICY_P((policy), BUFFER_DEFERRED_POP))                 \
+   if (BUFFERI_POLICY_P((policy), BUFFER_DEFERRED_POP)) {               \
+     /* If DEFERRED POP, number[0] can be modify outside the mutex */   \
+     atomic_fetch_add (&v->number[0], 1);                               \
      atomic_store (&v->number[1], atomic_load(&v->number[1]) + 1);      \
+   } else {                                                             \
+     /* No need for atomic_add: all access are protected */             \
+     atomic_store (&v->number[0], atomic_load(&v->number[0]) + 1);      \
+   }                                                                    \
                                                                         \
    /* BUFFER unlock */							\
    if (!BUFFERI_POLICY_P((policy), BUFFER_THREAD_UNSAFE)) {             \
@@ -387,7 +392,7 @@ M_C(name, _init)(buffer_t v, size_t size)                               \
  {                                                                      \
    /* Decrement the effective number of elements in the buffer */       \
    if (BUFFERI_POLICY_P((policy), BUFFER_DEFERRED_POP))                 \
-     atomic_store (&v->number[0], atomic_load(&v->number[0]) - 1);      \
+     atomic_fetch_sub (&v->number[0], 1);                               \
  }                                                                      \