On Thu, Nov 16, 2017 at 06:34:17PM +0100, Peter Zijlstra wrote: > On Thu, Nov 16, 2017 at 09:16:49AM -0800, Nick Desaulniers wrote: > > On Thu, Nov 16, 2017 at 8:59 AM, Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote: > > > On Thu, Nov 16, 2017 at 08:50:41AM -0800, Nick Desaulniers wrote: > > >> On Thu, Nov 16, 2017 at 8:30 AM, Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote: > > >> > > >> > Ideally we'd get the toolchain people to commit to supporting the kernel > > >> > memory model along side the C11 one. That would help a ton. > > >> > > >> Does anyone from the kernel side participate in the C standardization process? > > > > > > Yes, Paul McKenney and Will Deacon. Doesn't mean these two can still be > > > reconciled though. From what I understand C11 (and onwards) are > > > incompatible with the kernel model on a number of subtle points. > > > > It would be good to have these incompatibilities written down, then > > for the sake of argument, they can be cited both for discussions on > > LKML and in the C standardization process. For example, a running > > list in Documentation/ or something would make it so that anyone could > > understand and cite current issues with the latest C standard. > > Will should be able to produce this list; I know he's done before, I > just can't find it -- my Google-foo isn't strong today. Here you go: http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2017/p0124r4.html > > I don't understand why we'd block patches for enabling experimental > > features. We've been running this patch-set on actual devices for > > months and would love to provide them to the community for further > > testing. If bugs are found, then there's more evidence to bring to > > the C standards committee. Otherwise we're shutting down feature > > development for the sake of potential bugs in a C standard we're not > > even using. > > So the problem is that its very very hard (and painful) to find these > bugs. Getting the tools people to comment on these specific > optimizations would really help lots. It would be good to get something similar to LKMM into KTSAN, for example. There would probably be a few differences due to efficiency concerns, but closer is better than less close. ;-) Thanx, Paul -- To unsubscribe from this list: send the line "unsubscribe linux-kbuild" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
