Hi Paul, "Paul E. McKenney" <paulmck@xxxxxxxxxx> writes: >> > Yes, rcutorture has lower-level checks for CPUs being hotplugged >> > behind its back. Which might be sufficient. But this patch is in >> > response to something bad happening if the CPU is also not present in >> > the cpu_present_mask. Would that same bad thing happen if rcutorture saw >> > the CPU in cpu_online_mask, but by the time it attempted to CPU-hotplug >> > it, that CPU was gone not just from cpu_online_mask, but also from >> > cpu_present_mask? >> > >> > Or are CPUs never removed from cpu_present_mask? >> >> In the current implementation CPUs can only be added to the >> cpu_present_mask, but never removed. This might change in the future >> when we get support from firmware for that, but the current s390 code >> doesn't do that. > > Very good! > > Then could the patch please check that bits are never removed? > That way the code will complain should firmware support be added. > > Thanx, Paul I'm not sure whether i fully understand that. If the CPU could be removed from the system and the cpu_present_mask, that could happen at any time. So i don't see how we should check about that? Regards Sven
