Messages in this thread | | | Date | Fri, 22 Jun 2018 13:53:24 -0700 | From | "Paul E. McKenney" <> | Subject | Re: [PATCH 2/2] tools/memory-model: Add write ordering by release-acquire and by locks |
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On Fri, Jun 22, 2018 at 03:11:37PM -0400, Alan Stern wrote: > On Fri, 22 Jun 2018, Will Deacon wrote: > > On Fri, Jun 22, 2018 at 02:09:04PM -0400, Alan Stern wrote:
[ . . . ]
> > > > Could we drop the acquire/release stuff from the patch and limit this change > > > > to locking instead? > > > > > > The LKMM uses the same CAT code for acquire/release and lock/unlock. > > > (In essence, it considers a lock to be an acquire and an unlock to be a > > > release; everything else follows from that.) Treating one differently > > > from the other in these tests would require some significant changes. > > > It wouldn't be easy. > > > > It would be boring if it was easy ;) I think this is a case of the tail > > wagging the dog. > > > > Paul -- please can you drop this patch until we've resolved this discussion? > > Agreed. It sounds like we'll need two versions of the Rel and Acq sets > in the memory model; one for RCpc and one for RCsc. smp_load_acquire > and smp_store_release will use the former, and locking will use the > latter.
Done!
Thanx, Paul
> Would it suffice to have this duplication just for release, using a > single version of acquire? What would happen on ARMv8 or RISC-V if an > RCsc release was read by an RCpc acquire? Or vice versa? > > Alan >
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