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