* Nathan Lynch <nath...@linux.ibm.com> [2019-09-12 13:15:03]: > Srikar Dronamraju <sri...@linux.vnet.ibm.com> writes: > > >> > >> I think just WARN_ON(cpu_online(fcpu)) would be satisfactory. In my > >> experience, the downstream effects of violating this condition are > >> varied and quite difficult to debug. Seems only appropriate to emit a > >> warning and stack trace before the OS inevitably becomes unstable. > > > > I still have to try but wouldn't this be a problem for the boot-cpu? > > I mean boot-cpu would be marked online while it tries to do numa_setup_cpu. > > No? > > This is what I mean: > > + if (fcpu != lcpu) { > + WARN_ON(cpu_online(fcpu)); > + map_cpu_to_node(fcpu, nid); > + } >
Yes this should work. Will send an updated patch with this change. > I.e. if we're modifying the mapping for a remote cpu, warn if it's > online. > > I don't think this would warn on the boot cpu -- I would expect fcpu and > lcpu to be the same and this branch would not be taken. -- Thanks and Regards Srikar Dronamraju