On Mon 23-09-19 22:34:10, Peter Zijlstra wrote: > On Mon, Sep 23, 2019 at 06:52:35PM +0200, Michal Hocko wrote: [...] > > I even the > > ACPI standard is considering this optional. Yunsheng Lin has referred to > > the specific part of the standard in one of the earlier discussions. > > Trying to guess the node affinity is worse than providing all CPUs IMHO. > > I'm saying the ACPI standard is wrong. Even if you were right on this the reality is that a HW is likely to follow that standard and we cannot rule out NUMA_NO_NODE being specified. As of now we would access beyond the defined array and that is clearly a bug. Let's assume that this is really a bug for a moment. What are you going to do about that? BUG_ON? I do not really see any solution besides to either provide something sensible or BUG_ON. If you are worried about a conditional then this should be pretty easy to solve by starting the array at -1 index and associate it with the online cpu mask. -- Michal Hocko SUSE Labs
