On 01/18/2012 03:28 PM, Linus Torvalds wrote: > On Wed, Jan 18, 2012 at 1:53 PM, H. Peter Anvin <hpa@xxxxxxxxx> wrote: >> >> I think we can obviously agree that regsets is the only way to go for >> any kind of new state. > > So I really don't necessarily agree at all. > > Exactly because there is a heavy burden to introducing new models. > It's not only relatively much more kernel code, it's also relatively > much more painful for user code. If we can hide it in existing > structures, user code is *much* better off, because any existing code > to get the state will just continue to work. Otherwise, you need to > have the code to figure out the new structures (how do you compile it > without the new kernel headers?), you need to do the extra accesses > conditionally etc etc. > > There's a real cost to introducing new interfaces. There's a *reason* > people try to make do with old ones. > Of course. However, the whole point with regsets is that at the very least the vast majority of the infrastructure is generic and extends without a bunch of new machine. What you are saying is "we might be able to get away with existing state", what I'm saying is "if we add state it should be a regset". The question if this should be new state is currently open. I personally would still would prefer if this didn't overlay real CPU state. -hpa -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
