On Wed, Jul 13, 2016 at 12:20:20PM +0530, Bharata B Rao wrote: > If CPU core addition or removal is allowed in random order leading to > holes in the core id range (and hence in the cpu_index range), migration > can fail as migration with holes in cpu_index range isn't yet handled > correctly. > > Prevent this situation by enforcing the addition in contiguous order > and removal in LIFO order so that we never end up with holes in > cpu_index range. > > Signed-off-by: Bharata B Rao <bhar...@linux.vnet.ibm.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.
Applied to ppc-for-2.7. We can revert it once the problems with cpu_index are sorted out. > > hw/ppc/spapr_cpu_core.c | 21 ++++++++++++++++++++- > 1 file changed, 20 insertions(+), 1 deletion(-) > > diff --git a/hw/ppc/spapr_cpu_core.c b/hw/ppc/spapr_cpu_core.c > index bc52b3c..4bfc96b 100644 > --- a/hw/ppc/spapr_cpu_core.c > +++ b/hw/ppc/spapr_cpu_core.c > @@ -126,12 +126,23 @@ static void spapr_core_release(DeviceState *dev, void > *opaque) > void spapr_core_unplug(HotplugHandler *hotplug_dev, DeviceState *dev, > Error **errp) > { > + sPAPRMachineState *spapr = SPAPR_MACHINE(OBJECT(hotplug_dev)); > CPUCore *cc = CPU_CORE(dev); > sPAPRDRConnector *drc = > spapr_dr_connector_by_id(SPAPR_DR_CONNECTOR_TYPE_CPU, cc->core_id); > sPAPRDRConnectorClass *drck; > Error *local_err = NULL; > + int smt = kvmppc_smt_threads(); > + int index = cc->core_id / smt; > + int spapr_max_cores = max_cpus / smp_threads; > + int i; > > + for (i = spapr_max_cores - 1; i > index; i--) { > + if (spapr->cores[i]) { > + error_setg(errp, "core-id %d should be removed first", i * smt); > + return; > + } > + } > g_assert(drc); > > drck = SPAPR_DR_CONNECTOR_GET_CLASS(drc); > @@ -214,7 +225,7 @@ void spapr_core_pre_plug(HotplugHandler *hotplug_dev, > DeviceState *dev, > sPAPRMachineClass *smc = SPAPR_MACHINE_GET_CLASS(OBJECT(hotplug_dev)); > sPAPRMachineState *spapr = SPAPR_MACHINE(OBJECT(hotplug_dev)); > int spapr_max_cores = max_cpus / smp_threads; > - int index; > + int index, i; > int smt = kvmppc_smt_threads(); > Error *local_err = NULL; > CPUCore *cc = CPU_CORE(dev); > @@ -252,6 +263,14 @@ void spapr_core_pre_plug(HotplugHandler *hotplug_dev, > DeviceState *dev, > goto out; > } > > + for (i = 0; i < index; i++) { > + if (!spapr->cores[i]) { > + error_setg(&local_err, "core-id %d should be added first", > + i * smt); > + goto out; > + } > + } > + > out: > g_free(base_core_type); > error_propagate(errp, local_err); -- David Gibson | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_ | _way_ _around_! http://www.ozlabs.org/~dgibson
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