Messages in this thread Patch in this message | | | From | Kajol Jain <> | Subject | [RFC v2 4/4] powerpc/papr_scm: Add cpu hotplug support for nvdimm pmu device | Date | Tue, 25 May 2021 18:52:16 +0530 |
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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@linux.ibm.com> --- Documentation/ABI/testing/sysfs-bus-papr-pmem | 6 ++ arch/powerpc/platforms/pseries/papr_scm.c | 61 +++++++++++++++++++ include/linux/nd.h | 17 ++++-- 3 files changed, 79 insertions(+), 5 deletions(-)
diff --git a/Documentation/ABI/testing/sysfs-bus-papr-pmem b/Documentation/ABI/testing/sysfs-bus-papr-pmem index 38c4daf65af2..986df1691914 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@lists.ozlabs.org>, linux-nvdimm@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@lists.ozlabs.org>, linux-nvdimm@lists.01.org, diff --git a/arch/powerpc/platforms/pseries/papr_scm.c b/arch/powerpc/platforms/pseries/papr_scm.c index f2d57da98ff4..76121d876b7f 100644 --- a/arch/powerpc/platforms/pseries/papr_scm.c +++ b/arch/powerpc/platforms/pseries/papr_scm.c @@ -339,6 +339,28 @@ 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, +}; + PMU_FORMAT_ATTR(event, "config:0-4"); static struct attribute *nvdimm_pmu_format_attr[] = { @@ -459,6 +481,24 @@ static void papr_scm_pmu_del(struct perf_event *event, int flags) papr_scm_pmu_read(event); } +static int nvdimm_pmu_offline_cpu(unsigned int cpu, struct hlist_node *node) +{ + struct nvdimm_pmu *nd_pmu; + int target; + + nd_pmu = hlist_entry_safe(node, struct nvdimm_pmu, node); + + if (cpu != nd_pmu->cpu) + return 0; + + target = cpumask_last(cpu_active_mask); + if (target < 0 || target >= nr_cpu_ids) + return -1; + + nd_pmu->cpu = target; + return 0; +} + static ssize_t device_show_string(struct device *dev, struct device_attribute *attr, char *buf) { @@ -603,6 +643,7 @@ static int papr_scm_pmu_check_events(struct papr_scm_priv *p, struct nvdimm_pmu /* Fill attribute groups for the nvdimm pmu device */ nd_pmu->attr_groups[NVDIMM_PMU_FORMAT_ATTR] = &nvdimm_pmu_format_group; nd_pmu->attr_groups[NVDIMM_PMU_EVENT_ATTR] = nvdimm_pmu_events_group; + nd_pmu->attr_groups[NVDIMM_PMU_CPUMASK_ATTR] = &nvdimm_pmu_cpumask_group; nd_pmu->attr_groups[NVDIMM_PMU_NULL_ATTR] = NULL; kfree(single_stats); @@ -652,6 +693,20 @@ static void papr_scm_pmu_register(struct papr_scm_priv *p) nd_pmu->read = papr_scm_pmu_read; nd_pmu->add = papr_scm_pmu_add; nd_pmu->del = papr_scm_pmu_del; + nd_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) + goto pmu_cpuhp_setup_err; + + nd_pmu->cpuhp_state = rc; + + /* Register the pmu instance for cpu hotplug */ + rc = cpuhp_state_add_instance_nocalls(nd_pmu->cpuhp_state, &nd_pmu->node); + if (rc) + goto cpuhp_instance_err; rc = register_nvdimm_pmu(nd_pmu, p->pdev); if (rc) @@ -665,6 +720,10 @@ static void papr_scm_pmu_register(struct papr_scm_priv *p) return; pmu_register_err: + cpuhp_state_remove_instance_nocalls(nd_pmu->cpuhp_state, &nd_pmu->node); +cpuhp_instance_err: + cpuhp_remove_multi_state(nd_pmu->cpuhp_state); +pmu_cpuhp_setup_err: nvdimm_pmu_mem_free(nd_pmu); kfree(p->nvdimm_events_map); pmu_check_events_err: @@ -675,6 +734,8 @@ static void papr_scm_pmu_register(struct papr_scm_priv *p) static void nvdimm_pmu_uinit(struct nvdimm_pmu *nd_pmu) { + cpuhp_state_remove_instance_nocalls(nd_pmu->cpuhp_state, &nd_pmu->node); + cpuhp_remove_multi_state(nd_pmu->cpuhp_state); unregister_nvdimm_pmu(&nd_pmu->pmu); nvdimm_pmu_mem_free(nd_pmu); kfree(nd_pmu); diff --git a/include/linux/nd.h b/include/linux/nd.h index a0e0619256be..177795413ab3 100644 --- a/include/linux/nd.h +++ b/include/linux/nd.h @@ -28,7 +28,8 @@ enum nvdimm_claim_class { /* Event attribute array index */ #define NVDIMM_PMU_FORMAT_ATTR 0 #define NVDIMM_PMU_EVENT_ATTR 1 -#define NVDIMM_PMU_NULL_ATTR 2 +#define NVDIMM_PMU_CPUMASK_ATTR 2 +#define NVDIMM_PMU_NULL_ATTR 3 /** * struct nvdimm_pmu - data structure for nvdimm perf driver @@ -37,7 +38,10 @@ enum nvdimm_claim_class { * @pmu: pmu data structure for nvdimm performance stats. * @dev: nvdimm device pointer. * @functions(event_init/add/del/read): platform specific pmu functions. - * @attr_groups: data structure for events and formats. + * @attr_groups: data structure for events, formats and cpumask + * @cpu: designated cpu for counter access. + * @node: node for cpu hotplug notifier link. + * @cpuhp_state: state for cpu hotplug notification. */ struct nvdimm_pmu { const char *name; @@ -49,10 +53,13 @@ struct nvdimm_pmu { void (*read)(struct perf_event *event); /* * Attribute groups for the nvdimm pmu. Index 0 used for - * format attribute, index 1 used for event attribute and - * index 2 kept as NULL. + * format attribute, index 1 used for event attribute, + * index 2 used for cpusmask attribute and index 3 kept as NULL. */ - const struct attribute_group *attr_groups[3]; + const struct attribute_group *attr_groups[4]; + int cpu; + struct hlist_node node; + enum cpuhp_state cpuhp_state; }; int register_nvdimm_pmu(struct nvdimm_pmu *nvdimm, struct platform_device *pdev); -- 2.27.0
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