On Tue, Nov 16, 2010 at 09:44:18AM -0800, Matt Thomas wrote:
On Nov 16, 2010, at 9:10 AM, Alan Barrett wrote:
Please could somebody on the "eat your CAS whether you like it or not"
side of the fence explain why the following idea would not work:
On Sat, 13 Nov 2010, der Mouse wrote:
Arches without a sufficiently general CAS[%] do not define
ATOMIC_OPS_USE_CAS and provides their own implementations of mutexes,
spinlocks, whatever.
Because that flexibility already exists. A port can provide a full
mutex or rwlock implementation or use the default based on CAS primitives.
I think the question is about more about the naked use of atomic_cas_xxx
which are scattered around in the kernel.
Wouldn't those calls just use the slow implementation of CAS? I haven't
heard anyone saying that the vax port shouldn't (continue to) implement ai
CAS operation, just that it shouldn't be used for mutexes. And if those
naked uses of atomic_cas_xxx cause unreasonable slowness for that port,
well that's a separate problem.