···5555#define MAP_NONBLOCK 0x20000 /* do not block on IO */5656#define MAP_STACK 0x40000 /* give out an address that is best suited for process/thread stacks */5757#define MAP_HUGETLB 0x80000 /* create a huge page mapping */5858+#ifdef CONFIG_MMAP_ALLOW_UNINITIALIZED5959+# define MAP_UNINITIALIZED 0x4000000 /* For anonymous mmap, memory could be6060+ * uninitialized */6161+#else6262+# define MAP_UNINITIALIZED 0x0 /* Don't support this flag */6363+#endif58645965/*6066 * Flags for msync