linux/tools/memory-model/Documentation/cheatsheet.txt
Paul E. McKenney bfd403bb36 tools/memory-order: Update the cheat-sheet to show that smp_mb__after_atomic() orders later RMW operations
The current cheat sheet does not claim that smp_mb__after_atomic()
orders later RMW atomic operations, which it must, at least against
earlier RMW atomic operations and whatever precedes them.

This commit therefore adds the needed "Y".

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Cc: akiyks@gmail.com
Cc: boqun.feng@gmail.com
Cc: dhowells@redhat.com
Cc: j.alglave@ucl.ac.uk
Cc: linux-arch@vger.kernel.org
Cc: luc.maranget@inria.fr
Cc: npiggin@gmail.com
Cc: parri.andrea@gmail.com
Link: http://lkml.kernel.org/r/1526340837-12222-6-git-send-email-paulmck@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-05-15 08:11:16 +02:00

31 lines
1.7 KiB
Plaintext

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