RE: Synchronizing Bit operations V2

[Christoph Lameter]

On Thu, 30 Mar 2006, Chen, Kenneth W wrote:

> > > I know, I'm saying since it doesn't make any difference from API point of
> > > view whether it is acq, rel, or no ordering, then just make them rel as a
> > > "preferred" Operation on ia64.
> > 
> > That would make the behavior of clear_bit different from other bitops and 
> > references to volatile pointers. I'd like to have this as consistent as 
> > possible.
> 
> Yeah, but we just agreed that caller shouldn't be thinking clear_bit has
> memory ordering at all.

In general yes the caller should not be thinking about clear_bit having 
any memory ordering at all. However for IA64 arch specific code the bit 
operations must have a certain ordering semantic and it would be best that 
these are also consistent. clear_bit is not a lock operation and may 
f.e. be used for locking something.
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