| Paul E. McKenney | 1c27b64 | 2018-01-18 19:58:55 -0800 | [diff] [blame] | 1 | Prior Operation Subsequent Operation |
| 2 | --------------- --------------------------- |
| Paolo Bonzini | a839195 | 2018-05-14 16:33:42 -0700 | [diff] [blame] | 3 | C Self R W RMW Self R W DR DW RMW SV |
| Alan Stern | bd5c0ba | 2018-03-07 09:27:40 -0800 | [diff] [blame] | 4 | -- ---- - - --- ---- - - -- -- --- -- |
| Paul E. McKenney | 1c27b64 | 2018-01-18 19:58:55 -0800 | [diff] [blame] | 5 | |
| 6 | Store, e.g., WRITE_ONCE() Y Y |
| Alan Stern | bd5c0ba | 2018-03-07 09:27:40 -0800 | [diff] [blame] | 7 | Load, e.g., READ_ONCE() Y Y Y Y |
| 8 | Unsuccessful RMW operation Y Y Y Y |
| Alan Stern | bf28ae5 | 2018-02-20 15:25:12 -0800 | [diff] [blame] | 9 | rcu_dereference() Y Y Y Y |
| Paul E. McKenney | 1c27b64 | 2018-01-18 19:58:55 -0800 | [diff] [blame] | 10 | Successful *_acquire() R Y Y Y Y Y Y |
| 11 | Successful *_release() C Y Y Y W Y |
| 12 | smp_rmb() Y R Y Y R |
| 13 | smp_wmb() Y W Y Y W |
| 14 | smp_mb() & synchronize_rcu() CP Y Y Y Y Y Y Y Y |
| 15 | Successful full non-void RMW CP Y Y Y Y Y Y Y Y Y Y Y |
| 16 | smp_mb__before_atomic() CP Y Y Y a a a a Y |
| Paul E. McKenney | bfd403b | 2018-05-14 16:33:44 -0700 | [diff] [blame] | 17 | smp_mb__after_atomic() CP a a Y Y Y Y Y Y |
| Paul E. McKenney | 1c27b64 | 2018-01-18 19:58:55 -0800 | [diff] [blame] | 18 | |
| 19 | |
| 20 | Key: C: Ordering is cumulative |
| 21 | P: Ordering propagates |
| 22 | R: Read, for example, READ_ONCE(), or read portion of RMW |
| 23 | W: Write, for example, WRITE_ONCE(), or write portion of RMW |
| 24 | Y: Provides ordering |
| 25 | a: Provides ordering given intervening RMW atomic operation |
| 26 | DR: Dependent read (address dependency) |
| 27 | DW: Dependent write (address, data, or control dependency) |
| 28 | RMW: Atomic read-modify-write operation |
| Paul E. McKenney | 35bb6ee | 2018-05-14 16:33:43 -0700 | [diff] [blame] | 29 | SELF: Orders self, as opposed to accesses before and/or after |
| 30 | SV: Orders later accesses to the same variable |