2:38 a.m.
Patch here adds cpu hotplug functions to nvdimm pmu.
It adds cpumask to designate a cpu to make HCALL to
collect the counter data for the nvdimm device and
update ABI documentation accordingly.
Result in power9 lpar system:
command:# cat /sys/devices/nmem0/cpumask
0
Signed-off-by: Kajol Jain <kjain(a)linux.ibm.com>
---
Documentation/ABI/testing/sysfs-bus-papr-pmem | 6 ++
arch/powerpc/platforms/pseries/papr_scm.c | 62 +++++++++++++++++++
2 files changed, 68 insertions(+)
diff --git a/Documentation/ABI/testing/sysfs-bus-papr-pmem
b/Documentation/ABI/testing/sysfs-bus-papr-pmem
index 216f70deca7e..a40fbec683a8 100644
--- a/Documentation/ABI/testing/sysfs-bus-papr-pmem
+++ b/Documentation/ABI/testing/sysfs-bus-papr-pmem
@@ -76,6 +76,12 @@ Description: (RO) Attribute group to describe the magic bits
For example::
noopstat = "event=0x1"
+What: /sys/devices/nmemX/cpumask
+Date: May 2021
+Contact: linuxppc-dev <linuxppc-dev(a)lists.ozlabs.org>, linux-nvdimm(a)lists.01.org,
+Description: (RO) This sysfs file exposes the cpumask which is designated to make
+ HCALLs to retrieve nvdimm pmu event counter data.
+
What: /sys/devices/nmemX/events
Date: May 2021
Contact: linuxppc-dev <linuxppc-dev(a)lists.ozlabs.org>, linux-nvdimm(a)lists.01.org,
diff --git a/arch/powerpc/platforms/pseries/papr_scm.c
b/arch/powerpc/platforms/pseries/papr_scm.c
index 997d379094d0..6d94c2f260aa 100644
--- a/arch/powerpc/platforms/pseries/papr_scm.c
+++ b/arch/powerpc/platforms/pseries/papr_scm.c
@@ -334,6 +334,28 @@ static ssize_t drc_pmem_query_stats(struct papr_scm_priv *p,
return 0;
}
+static ssize_t cpumask_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct pmu *pmu = dev_get_drvdata(dev);
+ struct nvdimm_pmu *nd_pmu;
+
+ nd_pmu = container_of(pmu, struct nvdimm_pmu, pmu);
+
+ return cpumap_print_to_pagebuf(true, buf, cpumask_of(nd_pmu->cpu));
+}
+
+static DEVICE_ATTR_RO(cpumask);
+
+static struct attribute *nvdimm_cpumask_attrs[] = {
+ &dev_attr_cpumask.attr,
+ NULL,
+};
+
+static const struct attribute_group nvdimm_pmu_cpumask_group = {
+ .attrs = nvdimm_cpumask_attrs,
+};
+
static struct attribute_group nvdimm_pmu_events_group = {
.name = "events",
/* .attrs is set in papr_scm_pmu_check_events function */
@@ -354,6 +376,7 @@ static struct attribute_group nvdimm_pmu_format_group = {
static const struct attribute_group *nvdimm_pmu_attr_groups[] = {
&nvdimm_pmu_format_group,
&nvdimm_pmu_events_group,
+ &nvdimm_pmu_cpumask_group,
NULL,
};
@@ -418,10 +441,30 @@ static void papr_scm_pmu_del(struct perf_event *event, int flags,
struct device
papr_scm_pmu_read(event, dev);
}
+static int nvdimm_pmu_offline_cpu(unsigned int cpu, struct hlist_node *node)
+{
+ struct nvdimm_pmu *pmu;
+ int target;
+
+ pmu = hlist_entry_safe(node, struct nvdimm_pmu, node);
+
+ if (cpu != pmu->cpu)
+ return 0;
+
+ target = cpumask_last(cpu_active_mask);
+ if (target < 0 || target >= nr_cpu_ids)
+ return -1;
+
+ pmu->cpu = target;
+ return 0;
+}
+
static void nvdimm_pmu_uinit(struct nvdimm_pmu *nd_pmu)
{
unregister_nvdimm_pmu(&nd_pmu->pmu);
kfree(nd_pmu);
+ cpuhp_state_remove_instance_nocalls(nd_pmu->cpuhp_state, &nd_pmu->node);
+ cpuhp_remove_multi_state(nd_pmu->cpuhp_state);
}
static int papr_scm_pmu_register(struct papr_scm_priv *p)
@@ -438,6 +481,22 @@ static int papr_scm_pmu_register(struct papr_scm_priv *p)
papr_scm_pmu->add = papr_scm_pmu_add;
papr_scm_pmu->del = papr_scm_pmu_del;
papr_scm_pmu->attr_groups = nvdimm_pmu_attr_groups;
+ papr_scm_pmu->cpu = raw_smp_processor_id();
+
+ rc = cpuhp_setup_state_multi(CPUHP_AP_ONLINE_DYN,
+ "perf/nvdimm:online",
+ NULL, nvdimm_pmu_offline_cpu);
+ if (rc < 0) {
+ kfree(papr_scm_pmu);
+ return rc;
+ }
+
+ papr_scm_pmu->cpuhp_state = rc;
+
+ /* Register the pmu instance for cpu hotplug */
+ rc = cpuhp_state_add_instance_nocalls(papr_scm_pmu->cpuhp_state,
&papr_scm_pmu->node);
+ if (rc)
+ goto cpuhp_instance_err;
rc = register_nvdimm_pmu(papr_scm_pmu, p->pdev);
if (rc)
@@ -451,6 +510,9 @@ static int papr_scm_pmu_register(struct papr_scm_priv *p)
return 0;
pmu_register_err:
+ cpuhp_state_remove_instance_nocalls(papr_scm_pmu->cpuhp_state,
&papr_scm_pmu->node);
+cpuhp_instance_err:
+ cpuhp_remove_multi_state(papr_scm_pmu->cpuhp_state);
kfree(papr_scm_pmu);
return rc;
}
--
2.27.0