> On Oct 31, 2018, at 3:11 AM, Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote: > >> On Wed, Oct 31, 2018 at 12:15:46AM +0200, Igor Stoppa wrote: >> On 30/10/2018 23:02, Andy Lutomirski wrote: > >>> But I dislike allowing regular writes in the protected region. We >>> really only need four write primitives: >>> >>> 1. Just write one value. Call at any time (except NMI). >>> >>> 2. Just copy some bytes. Same as (1) but any number of bytes. >>> >>> 3,4: Same as 1 and 2 but must be called inside a special rare write >>> region. This is purely an optimization. >> >> Atomic? RCU? > > RCU can be done, that's not really a problem. Atomics otoh are a > problem. Having pointers makes them just work. > > Andy; I understand your reason for not wanting them, but I really don't > want to duplicate everything. Is there something we can do with static > analysis to make you more comfortable with the pointer thing? I’m sure we could do something with static analysis, but I think seeing a real use case where all this fanciness makes sense would be good. And I don’t know if s390 *can* have an efficient implementation that uses pointers. OTOH they have all kinds of magic stuff, so who knows?
