Igor Mammedov <imamm...@redhat.com> writes: > On Thu, 14 Jul 2016 14:10:24 -0400 > Bandan Das <b...@redhat.com> wrote: > >> Igor Mammedov <imamm...@redhat.com> writes: >> >> > it will still allow us to use cpu_index as migration instance_id >> > since when CPUs are added contiguously (from the first to the last) >> > and removed in opposite order, cpu_index stays stable and it's >> > reproducable on destination side. >> > >> > Signed-off-by: Igor Mammedov <imamm...@redhat.com> >> > --- >> > While there is work in progress to support migration when there are holes >> > in cpu_index range resulting from out-of-order plug or unplug, this patch >> > is intended as a last resort if no easy, risk-free and elegant solution >> > emerges before 2.7 dev cycle ends. >> >> I think this (or a modified version) is appropriate comment >> material to accompany the changes. Ok if you are sure this code >> is short-lived, but if it stays longer, a comment is definitely >> helpful. Maybe a bit of reasoning added to the error message is >> fine too. > dwg is looking at cpu_index refactoring but that's not 2.7 material, > this patch is doing what the similar spapr patch did > (which David applied to his ppc queue). > > Perhaps moving comment under --- to commit message itself would > be better as to leave trace of future refactoring plans.
Right, sounds good. >> > --- >> > hw/i386/pc.c | 34 ++++++++++++++++++++++++++++++++++ >> > 1 file changed, 34 insertions(+) >> > >> > diff --git a/hw/i386/pc.c b/hw/i386/pc.c >> > index 33c5f97..75a92d0 100644 >> > --- a/hw/i386/pc.c >> > +++ b/hw/i386/pc.c >> > @@ -1762,6 +1762,23 @@ static void pc_cpu_unplug_request_cb(HotplugHandler >> > *hotplug_dev, >> > goto out; >> > } >> > >> > + if (idx < pcms->possible_cpus->len - 1 && >> > + pcms->possible_cpus->cpus[idx + 1].cpu != NULL) { >> > + X86CPU *cpu; >> > + >> > + for (idx = pcms->possible_cpus->len - 1; >> > + pcms->possible_cpus->cpus[idx].cpu == NULL; idx--) { >> > + ;; >> > + } >> > + >> > + cpu = X86_CPU(pcms->possible_cpus->cpus[idx].cpu); >> > + error_setg(&local_err, "CPU [socket-id: %u, core-id: %u," >> > + " thread-id: %u] should be removed first", >> > + cpu->socket_id, cpu->core_id, cpu->thread_id); >> > + goto out; >> > + >> > + } >> > + >> > hhc = HOTPLUG_HANDLER_GET_CLASS(pcms->acpi_dev); >> > hhc->unplug_request(HOTPLUG_HANDLER(pcms->acpi_dev), dev, &local_err); >> > >> > @@ -1860,6 +1877,23 @@ static void pc_cpu_pre_plug(HotplugHandler >> > *hotplug_dev, >> > return; >> > } >> > >> > + if (idx != 0 && pcms->possible_cpus->cpus[idx - 1].cpu == NULL) { >> > + PCMachineClass *pcmc = PC_MACHINE_GET_CLASS(pcms); >> > + >> > + for (idx = 1; pcms->possible_cpus->cpus[idx].cpu != NULL; idx++) { >> > + ;; >> > + } >> > + >> > + x86_topo_ids_from_apicid(pcms->possible_cpus->cpus[idx].arch_id, >> > + smp_cores, smp_threads, &topo); >> > + >> > + if (!pcmc->legacy_cpu_hotplug) { >> > + error_setg(errp, "CPU [socket: %u, core: %u, thread: %u] >> > should be" >> > + " added first", topo.pkg_id, topo.core_id, >> > topo.smt_id); >> > + return; >> > + } >> > + } >> > + >> > /* if 'address' properties socket-id/core-id/thread-id are not set, >> > set them >> > * so that query_hotpluggable_cpus would show correct values >> > */