diff options
Diffstat (limited to 'include/uapi/linux/membarrier.h')
| -rw-r--r-- | include/uapi/linux/membarrier.h | 23 |
1 files changed, 21 insertions, 2 deletions
diff --git a/include/uapi/linux/membarrier.h b/include/uapi/linux/membarrier.h index e0b108bd2624..6d47b3249d8a 100644 --- a/include/uapi/linux/membarrier.h +++ b/include/uapi/linux/membarrier.h @@ -40,14 +40,33 @@ * (non-running threads are de facto in such a * state). This covers threads from all processes * running on the system. This command returns 0. + * @MEMBARRIER_CMD_PRIVATE_EXPEDITED: + * Execute a memory barrier on each running + * thread belonging to the same process as the current + * thread. Upon return from system call, the + * caller thread is ensured that all its running + * threads siblings have passed through a state + * where all memory accesses to user-space + * addresses match program order between entry + * to and return from the system call + * (non-running threads are de facto in such a + * state). This only covers threads from the + * same processes as the caller thread. This + * command returns 0. The "expedited" commands + * complete faster than the non-expedited ones, + * they never block, but have the downside of + * causing extra overhead. * * Command to be passed to the membarrier system call. The commands need to * be a single bit each, except for MEMBARRIER_CMD_QUERY which is assigned to * the value 0. */ enum membarrier_cmd { - MEMBARRIER_CMD_QUERY = 0, - MEMBARRIER_CMD_SHARED = (1 << 0), + MEMBARRIER_CMD_QUERY = 0, + MEMBARRIER_CMD_SHARED = (1 << 0), + /* reserved for MEMBARRIER_CMD_SHARED_EXPEDITED (1 << 1) */ + /* reserved for MEMBARRIER_CMD_PRIVATE (1 << 2) */ + MEMBARRIER_CMD_PRIVATE_EXPEDITED = (1 << 3), }; #endif /* _UAPI_LINUX_MEMBARRIER_H */ |