On Thu, Sep 03, 2020 at 07:39:55PM -0700, Paul E. McKenney wrote: > On Fri, Sep 04, 2020 at 08:59:21AM +0800, Boqun Feng wrote: > > On Thu, Sep 03, 2020 at 04:30:37PM -0700, Paul E. McKenney wrote: > > [ . . . ] > > > > How about like this, adding "Relaxed" to the WRITE_ONCE() and READ_ONCE() > > > rows and "RMW" to the "Relaxed operation" row? > > > > > > > Much better now, thanks! However ... > > > > > The file contents are followed by a diff against the previous version. > > > > > > Thanx, Paul > > > > > > ------------------------------------------------------------------------ > > [ . . . ] > > > > Key: Relaxed: A relaxed operation is either a *_relaxed() RMW > > > operation, an unsuccessful RMW operation, READ_ONCE(), > > > WRITE_ONCE(), or one of the atomic_read() and > > > atomic_set() family of operations. > > > > And: > > a RMW operation that doesn't return any value (e.g > > atomic_inc()), IOW it's a void Relaxed operation. > > Good point! Please see below. > Looks good to me ;-) Acked-by: Boqun Feng <boqun.feng@xxxxxxxxx> Regards, Boqun > Thanx, Paul > > ------------------------------------------------------------------------ > > Prior Operation Subsequent Operation > --------------- --------------------------- > C Self R W RMW Self R W DR DW RMW SV > -- ---- - - --- ---- - - -- -- --- -- > > Relaxed store Y Y > Relaxed load Y Y Y Y > Relaxed 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: Relaxed: A relaxed operation is either READ_ONCE(), WRITE_ONCE(), > a *_relaxed() RMW operation, an unsuccessful RMW > operation, a non-value-returning RMW operation such > as atomic_inc(), or one of the atomic*_read() and > atomic*_set() family of operations. > 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 > > ------------------------------------------------------------------------ > > diff --git a/tools/memory-model/Documentation/cheatsheet.txt b/tools/memory-model/Documentation/cheatsheet.txt > index 4146b8d..99d0087 100644 > --- a/tools/memory-model/Documentation/cheatsheet.txt > +++ b/tools/memory-model/Documentation/cheatsheet.txt > @@ -17,10 +17,11 @@ 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: Relaxed: A relaxed operation is either a *_relaxed() RMW > - operation, an unsuccessful RMW operation, READ_ONCE(), > - WRITE_ONCE(), or one of the atomic_read() and > - atomic_set() family of operations. > +Key: Relaxed: A relaxed operation is either READ_ONCE(), WRITE_ONCE(), > + a *_relaxed() RMW operation, an unsuccessful RMW > + operation, a non-value-returning RMW operation such > + as atomic_inc(), or one of the atomic*_read() and > + atomic*_set() family of operations. > C: Ordering is cumulative > P: Ordering propagates > R: Read, for example, READ_ONCE(), or read portion of RMW
