diff --git a/src/activity.c b/src/activity.c
index 4dc832e..7d2ddac 100644
--- a/src/activity.c
+++ b/src/activity.c
@@ -281,10 +281,10 @@
 	bin = memprof_get_bin(__builtin_return_address(0));
 	if (size > size_before) {
 		_HA_ATOMIC_ADD(&bin->alloc_calls, 1);
-		_HA_ATOMIC_ADD(&bin->alloc_tot, size);
+		_HA_ATOMIC_ADD(&bin->alloc_tot, size - size_before);
 	} else if (size < size_before) {
 		_HA_ATOMIC_ADD(&bin->free_calls, 1);
-		_HA_ATOMIC_ADD(&bin->free_tot, size_before);
+		_HA_ATOMIC_ADD(&bin->free_tot, size_before - size);
 	}
 	return ret;
 }