diff --git a/executer/user/mcexec.c b/executer/user/mcexec.c
index 6b4488d7..6e911d88 100644
--- a/executer/user/mcexec.c
+++ b/executer/user/mcexec.c
@@ -195,7 +195,7 @@ static int mpol_no_bss = 0;
 static int mpol_shm_premap = 0;
 static int no_bind_ikc_map = 0;
 static unsigned long mpol_threshold = 0;
-static unsigned long heap_extension = (4*1024);
+static unsigned long heap_extension = -1;
 static int profile = 0;
 static int disable_sched_yield = 0;
 static long stack_premap = (2ULL << 20);
@@ -2234,6 +2234,10 @@ int main(int argc, char **argv)
 		}
 	}
 
+	if (heap_extension == -1) {
+		heap_extension = sysconf(_SC_PAGESIZE);
+	}
+
 	if (optind >= argc) {
 		print_usage(argv);
 		exit(EXIT_FAILURE);