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- Prior Operation Subsequent Operation
- --------------- ---------------------------
- C Self R W RMW Self R W DR DW RMW SV
- -- ---- - - --- ---- - - -- -- --- --
- Store, e.g., WRITE_ONCE() Y Y
- Load, e.g., READ_ONCE() Y Y Y Y
- Unsuccessful RMW operation Y Y Y Y
- rcu_dereference() Y Y Y Y
- Successful *_acquire() R Y Y Y Y Y Y
- Successful *_release() C Y Y Y W Y
- smp_rmb() Y R Y Y R
- smp_wmb() Y W Y Y W
- smp_mb() & synchronize_rcu() CP Y Y Y Y Y Y Y Y
- Successful full non-void RMW CP Y Y Y Y Y Y Y Y Y Y Y
- smp_mb__before_atomic() CP Y Y Y a a a a Y
- smp_mb__after_atomic() CP a a Y Y Y Y Y Y
- Key: C: Ordering is cumulative
- P: Ordering propagates
- R: Read, for example, READ_ONCE(), or read portion of RMW
- W: Write, for example, WRITE_ONCE(), or write portion of RMW
- Y: Provides ordering
- a: Provides ordering given intervening RMW atomic operation
- DR: Dependent read (address dependency)
- DW: Dependent write (address, data, or control dependency)
- RMW: Atomic read-modify-write operation
- SELF: Orders self, as opposed to accesses before and/or after
- SV: Orders later accesses to the same variable
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