On Mon, Aug 03, 2015 at 03:29:58PM +0200, Peter Zijlstra wrote: > On Mon, Aug 03, 2015 at 03:09:39PM +0200, Frederic Weisbecker wrote: > > > > That doesn't make any sense: > > > > > > tick_nohz_set_tick_dependency_this_cpu(); > > > > > > (shees, you're nowhere near lazy enough, that's insane to type) is > > > almost identical to: > > > > > > tick_nohz_set_tick_dependency_cpu(.cpu = smp_processor_id()); > > > > > > The only difference is a _very_ slight reduction in cost for computing > > > the per-cpu offset. > > > > But the local one must be NMI-safe. Now I can do: > > > > if (cpu == smp_processor_id()) > > tick_nohz_full_kick() // NMI-safe > > else > > tick_nohz_full_kick_cpu(cpu); // not NMI-safe. > > Urgh, I missed that. But yes, I suppose that's ok seeing how we result > in a smaller interface. > > I was going to say that with a bit of luck GCC could optimize it, but > its not inline so no it cannot.
I might inline all these set_dep() things to introduce static keys on these APIs.. But the kick itself will remain real calls. Ok how about tick_nohz_set_dep_nmi() so that we know exactly what's the purpose here. Still a long function name but it's clear. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
