spapr: disintricate core-id from DT semantics

The goal of this patch is to have a stable core-id which does not depend
on any DT related semantics, which involve non-obvious computations on
modern PowerPC server cpus.

With this patch, the DT core id is computed on-demand as:

       (core-id / smp_threads) * smt

where smt is the number of threads per core in the host.

This formula should be consolidated in a helper since it is needed in
several places.

Other uses for core-id includes: compute a stable cpu_index (which
allows random order hotplug/unplug without breaking migration) and
NUMA.

Signed-off-by: Greg Kurz <groug@kaod.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
This commit is contained in:
Greg Kurz 2016-07-22 13:10:36 +02:00 committed by David Gibson
parent 2fff4bad40
commit 12bf2d33fe
2 changed files with 16 additions and 18 deletions

View file

@ -1815,10 +1815,11 @@ static void ppc_spapr_init(MachineState *machine)
spapr->cores = g_new0(Object *, spapr_max_cores); spapr->cores = g_new0(Object *, spapr_max_cores);
for (i = 0; i < spapr_max_cores; i++) { for (i = 0; i < spapr_max_cores; i++) {
int core_dt_id = i * smt; int core_id = i * smp_threads;
sPAPRDRConnector *drc = sPAPRDRConnector *drc =
spapr_dr_connector_new(OBJECT(spapr), spapr_dr_connector_new(OBJECT(spapr),
SPAPR_DR_CONNECTOR_TYPE_CPU, core_dt_id); SPAPR_DR_CONNECTOR_TYPE_CPU,
(core_id / smp_threads) * smt);
qemu_register_reset(spapr_drc_reset, drc); qemu_register_reset(spapr_drc_reset, drc);
@ -1834,7 +1835,7 @@ static void ppc_spapr_init(MachineState *machine)
core = object_new(type); core = object_new(type);
object_property_set_int(core, smp_threads, "nr-threads", object_property_set_int(core, smp_threads, "nr-threads",
&error_fatal); &error_fatal);
object_property_set_int(core, core_dt_id, CPU_CORE_PROP_CORE_ID, object_property_set_int(core, core_id, CPU_CORE_PROP_CORE_ID,
&error_fatal); &error_fatal);
object_property_set_bool(core, true, "realized", &error_fatal); object_property_set_bool(core, true, "realized", &error_fatal);
} }
@ -2376,7 +2377,6 @@ static HotpluggableCPUList *spapr_query_hotpluggable_cpus(MachineState *machine)
HotpluggableCPUList *head = NULL; HotpluggableCPUList *head = NULL;
sPAPRMachineState *spapr = SPAPR_MACHINE(machine); sPAPRMachineState *spapr = SPAPR_MACHINE(machine);
int spapr_max_cores = max_cpus / smp_threads; int spapr_max_cores = max_cpus / smp_threads;
int smt = kvmppc_smt_threads();
for (i = 0; i < spapr_max_cores; i++) { for (i = 0; i < spapr_max_cores; i++) {
HotpluggableCPUList *list_item = g_new0(typeof(*list_item), 1); HotpluggableCPUList *list_item = g_new0(typeof(*list_item), 1);
@ -2386,7 +2386,7 @@ static HotpluggableCPUList *spapr_query_hotpluggable_cpus(MachineState *machine)
cpu_item->type = spapr_get_cpu_core_type(machine->cpu_model); cpu_item->type = spapr_get_cpu_core_type(machine->cpu_model);
cpu_item->vcpus_count = smp_threads; cpu_item->vcpus_count = smp_threads;
cpu_props->has_core_id = true; cpu_props->has_core_id = true;
cpu_props->core_id = i * smt; cpu_props->core_id = i * smp_threads;
/* TODO: add 'has_node/node' here to describe /* TODO: add 'has_node/node' here to describe
to which node core belongs */ to which node core belongs */

View file

@ -103,7 +103,6 @@ static void spapr_core_release(DeviceState *dev, void *opaque)
size_t size = object_type_get_instance_size(typename); size_t size = object_type_get_instance_size(typename);
sPAPRMachineState *spapr = SPAPR_MACHINE(qdev_get_machine()); sPAPRMachineState *spapr = SPAPR_MACHINE(qdev_get_machine());
CPUCore *cc = CPU_CORE(dev); CPUCore *cc = CPU_CORE(dev);
int smt = kvmppc_smt_threads();
int i; int i;
for (i = 0; i < cc->nr_threads; i++) { for (i = 0; i < cc->nr_threads; i++) {
@ -117,7 +116,7 @@ static void spapr_core_release(DeviceState *dev, void *opaque)
object_unparent(obj); object_unparent(obj);
} }
spapr->cores[cc->core_id / smt] = NULL; spapr->cores[cc->core_id / smp_threads] = NULL;
g_free(sc->threads); g_free(sc->threads);
object_unparent(OBJECT(dev)); object_unparent(OBJECT(dev));
@ -128,18 +127,19 @@ void spapr_core_unplug(HotplugHandler *hotplug_dev, DeviceState *dev,
{ {
sPAPRMachineState *spapr = SPAPR_MACHINE(OBJECT(hotplug_dev)); sPAPRMachineState *spapr = SPAPR_MACHINE(OBJECT(hotplug_dev));
CPUCore *cc = CPU_CORE(dev); CPUCore *cc = CPU_CORE(dev);
int smt = kvmppc_smt_threads();
int index = cc->core_id / smp_threads;
sPAPRDRConnector *drc = sPAPRDRConnector *drc =
spapr_dr_connector_by_id(SPAPR_DR_CONNECTOR_TYPE_CPU, cc->core_id); spapr_dr_connector_by_id(SPAPR_DR_CONNECTOR_TYPE_CPU, index * smt);
sPAPRDRConnectorClass *drck; sPAPRDRConnectorClass *drck;
Error *local_err = NULL; Error *local_err = NULL;
int smt = kvmppc_smt_threads();
int index = cc->core_id / smt;
int spapr_max_cores = max_cpus / smp_threads; int spapr_max_cores = max_cpus / smp_threads;
int i; int i;
for (i = spapr_max_cores - 1; i > index; i--) { for (i = spapr_max_cores - 1; i > index; i--) {
if (spapr->cores[i]) { if (spapr->cores[i]) {
error_setg(errp, "core-id %d should be removed first", i * smt); error_setg(errp, "core-id %d should be removed first",
i * smp_threads);
return; return;
} }
} }
@ -168,11 +168,10 @@ void spapr_core_plug(HotplugHandler *hotplug_dev, DeviceState *dev,
Error *local_err = NULL; Error *local_err = NULL;
void *fdt = NULL; void *fdt = NULL;
int fdt_offset = 0; int fdt_offset = 0;
int index; int index = cc->core_id / smp_threads;
int smt = kvmppc_smt_threads(); int smt = kvmppc_smt_threads();
drc = spapr_dr_connector_by_id(SPAPR_DR_CONNECTOR_TYPE_CPU, cc->core_id); drc = spapr_dr_connector_by_id(SPAPR_DR_CONNECTOR_TYPE_CPU, index * smt);
index = cc->core_id / smt;
spapr->cores[index] = OBJECT(dev); spapr->cores[index] = OBJECT(dev);
if (!smc->dr_cpu_enabled) { if (!smc->dr_cpu_enabled) {
@ -226,7 +225,6 @@ void spapr_core_pre_plug(HotplugHandler *hotplug_dev, DeviceState *dev,
sPAPRMachineState *spapr = SPAPR_MACHINE(OBJECT(hotplug_dev)); sPAPRMachineState *spapr = SPAPR_MACHINE(OBJECT(hotplug_dev));
int spapr_max_cores = max_cpus / smp_threads; int spapr_max_cores = max_cpus / smp_threads;
int index, i; int index, i;
int smt = kvmppc_smt_threads();
Error *local_err = NULL; Error *local_err = NULL;
CPUCore *cc = CPU_CORE(dev); CPUCore *cc = CPU_CORE(dev);
char *base_core_type = spapr_get_cpu_core_type(machine->cpu_model); char *base_core_type = spapr_get_cpu_core_type(machine->cpu_model);
@ -247,12 +245,12 @@ void spapr_core_pre_plug(HotplugHandler *hotplug_dev, DeviceState *dev,
goto out; goto out;
} }
if (cc->core_id % smt) { if (cc->core_id % smp_threads) {
error_setg(&local_err, "invalid core id %d\n", cc->core_id); error_setg(&local_err, "invalid core id %d\n", cc->core_id);
goto out; goto out;
} }
index = cc->core_id / smt; index = cc->core_id / smp_threads;
if (index < 0 || index >= spapr_max_cores) { if (index < 0 || index >= spapr_max_cores) {
error_setg(&local_err, "core id %d out of range", cc->core_id); error_setg(&local_err, "core id %d out of range", cc->core_id);
goto out; goto out;
@ -266,7 +264,7 @@ void spapr_core_pre_plug(HotplugHandler *hotplug_dev, DeviceState *dev,
for (i = 0; i < index; i++) { for (i = 0; i < index; i++) {
if (!spapr->cores[i]) { if (!spapr->cores[i]) {
error_setg(&local_err, "core-id %d should be added first", error_setg(&local_err, "core-id %d should be added first",
i * smt); i * smp_threads);
goto out; goto out;
} }
} }