On Fri, Sep 29, 2017 at 09:38:53PM +1000, Nicholas Piggin wrote: > Not really. There is some ability to hold onto a line for a time, but > there is no way to starve them, let alone starve hundreds of other > CPUs. They will request the cacheline exclusive and eventually get it. OK, hardware fairness there is nice. > I would really prefer to go this way on powerpc first. We could add the > the registration APIs as basically no-ops, but which would allow the > locking approach to be changed if we find it causes issues. I'll try to > find some time and a big system when I can. Fair enough I suppose. > > A semi related issue; I suppose we can do a arch upcall to flush_tlb_mm > > and reset the mm_cpumask when we change cpuset groups. > > For powerpc we have been looking at how mm_cpumask can be improved. > It has real drawbacks even when you don't consider this new syscall. What else do you use mm_cpumask for?
