mcexec: --extend-heap-by: argument to specify heap extension size

kernel/include/process.h

@@ -534,9 +534,10 @@ struct process {
 
 	long maxrss;
 	long maxrss_children;
-	/* Memory policy flags */
+	/* Memory policy flags and memory specific options */
 	unsigned long mpol_flags;
 	size_t mpol_threshold;
+	unsigned long heap_extension;
 
 	// perf_event
 	int perf_status;

kernel/include/syscall.h

@@ -194,6 +194,7 @@ struct program_load_desc {
 	unsigned long interp_align;
 	unsigned long mpol_flags;
 	unsigned long mpol_threshold;
+	unsigned long heap_extension;
 	int nr_processes;
 	char shell_path[SHELL_PATH_MAX_LEN];
 	__cpu_set_unit cpu_set[PLD_CPU_SET_SIZE];