Messages in this thread Patch in this message |  | | From | Kajol Jain <> | Subject | [RFC v3 2/4] drivers/nvdimm: Add perf interface to expose nvdimm performance stats | Date | Sat, 29 May 2021 13:08:26 +0530 |
| |
A common interface is added to get performance stats reporting support for nvdimm devices. Added interface includes support for pmu register/unregister functions which can be used to set arch/platform specific data such as supported events and pmu event functions like event_init/add/read/del. User could use the standard perf tool to access perf events exposed via pmu.
Interface also adds cpu hotplug functions to nvdimm pmu incase its not added by arch/platform specific code. It will adds cpumask to the nvdimm pmu to designate a cpu to collect the counter data.
Signed-off-by: Kajol Jain <kjain@linux.ibm.com> --- drivers/nvdimm/Makefile | 1 + drivers/nvdimm/nd_perf.c | 195 +++++++++++++++++++++++++++++++++++++++ include/linux/nd.h | 3 + 3 files changed, 199 insertions(+) create mode 100644 drivers/nvdimm/nd_perf.c
diff --git a/drivers/nvdimm/Makefile b/drivers/nvdimm/Makefile index 29203f3d3069..25dba6095612 100644 --- a/drivers/nvdimm/Makefile +++ b/drivers/nvdimm/Makefile @@ -18,6 +18,7 @@ nd_e820-y := e820.o libnvdimm-y := core.o libnvdimm-y += bus.o libnvdimm-y += dimm_devs.o +libnvdimm-y += nd_perf.o libnvdimm-y += dimm.o libnvdimm-y += region_devs.o libnvdimm-y += region.o diff --git a/drivers/nvdimm/nd_perf.c b/drivers/nvdimm/nd_perf.c new file mode 100644 index 000000000000..a7679699118a --- /dev/null +++ b/drivers/nvdimm/nd_perf.c @@ -0,0 +1,195 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * nd_perf.c: NVDIMM Device Performance Monitoring Unit support + * + * Perf interface to expose nvdimm performance stats. + * + * Copyright (C) 2021 IBM Corporation + */ + +#define pr_fmt(fmt) "nvdimm_pmu: " fmt + +#include <linux/nd.h> + +static ssize_t nvdimm_pmu_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 int nvdimm_pmu_offline_cpu(unsigned int cpu, struct hlist_node *node) +{ + struct nvdimm_pmu *nd_pmu; + int target, nodeid; + const struct cpumask *cpumask; + + nd_pmu = hlist_entry_safe(node, struct nvdimm_pmu, node); + + if (!nd_pmu->dev) + return -1; + + if (cpu != nd_pmu->cpu) + return 0; + + /* + * here function dev_to_node will return node id for given nvdimm device + * which need to be assigned to variable nodeid but incase that node is + * offline, numa_map_to_online_node function will lookup for next + * closest online node and assigned that value to nodeid. + */ + nodeid = numa_map_to_online_node(dev_to_node(nd_pmu->dev)); + + cpumask = cpumask_of_node(nodeid); + target = cpumask_any_but(cpumask, cpu); + nd_pmu->cpu = target; + + if (target < 0 || target >= nr_cpu_ids) + return -1; + + return 0; +} + +static int create_cpumask_attr_group(struct nvdimm_pmu *nd_pmu) +{ + struct perf_pmu_events_attr *attr; + struct attribute **attrs; + struct attribute_group *nvdimm_pmu_cpumask_group; + + attr = kzalloc(sizeof(*attr), GFP_KERNEL); + if (!attr) + return -ENOMEM; + + attrs = kzalloc(2 * sizeof(struct attribute *), GFP_KERNEL); + if (!attrs) { + kfree(attr); + return -ENOMEM; + } + + /* Allocate memory for cpumask attribute group */ + nvdimm_pmu_cpumask_group = kzalloc(sizeof(*nvdimm_pmu_cpumask_group), GFP_KERNEL); + if (!nvdimm_pmu_cpumask_group) { + kfree(attr); + kfree(attrs); + return -ENOMEM; + } + + sysfs_attr_init(&attr->attr.attr); + attr->attr.attr.name = "cpumask"; + attr->attr.attr.mode = 0444; + attr->attr.show = nvdimm_pmu_cpumask_show; + attrs[0] = &attr->attr.attr; + attrs[1] = NULL; + + nvdimm_pmu_cpumask_group->attrs = attrs; + nd_pmu->attr_groups[NVDIMM_PMU_CPUMASK_ATTR] = nvdimm_pmu_cpumask_group; + return 0; +} + +static int nvdimm_pmu_cpu_hotplug_init(struct nvdimm_pmu *nd_pmu) +{ + int nodeid, rc; + const struct cpumask *cpumask; + + nodeid = numa_map_to_online_node(dev_to_node(nd_pmu->dev)); + cpumask = cpumask_of_node(nodeid); + nd_pmu->cpu = cpumask_any(cpumask); + + rc = cpuhp_setup_state_multi(CPUHP_AP_ONLINE_DYN, "perf/nvdimm:online", + NULL, nvdimm_pmu_offline_cpu); + + if (rc < 0) + return rc; + + 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) { + cpuhp_remove_multi_state(nd_pmu->cpuhp_state); + return rc; + } + + /* Create cpumask attribute group */ + rc = create_cpumask_attr_group(nd_pmu); + if (rc) { + cpuhp_state_remove_instance_nocalls(nd_pmu->cpuhp_state, &nd_pmu->node); + cpuhp_remove_multi_state(nd_pmu->cpuhp_state); + return rc; + } + + return 0; +} + +void nvdimm_pmu_free_hotplug_memory(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); + + if (nd_pmu->attr_groups[NVDIMM_PMU_CPUMASK_ATTR]) + kfree(nd_pmu->attr_groups[NVDIMM_PMU_CPUMASK_ATTR]->attrs); + kfree(nd_pmu->attr_groups[NVDIMM_PMU_CPUMASK_ATTR]); +} + +int register_nvdimm_pmu(struct nvdimm_pmu *nd_pmu, struct platform_device *pdev) +{ + int rc; + + if (!nd_pmu || !pdev) + return -EINVAL; + + /* event functions like add/del/read/event_init should not be NULL */ + if (WARN_ON_ONCE(!(nd_pmu->event_init && nd_pmu->add && nd_pmu->del && nd_pmu->read))) + return -EINVAL; + + nd_pmu->pmu.task_ctx_nr = perf_invalid_context; + nd_pmu->pmu.name = nd_pmu->name; + nd_pmu->pmu.event_init = nd_pmu->event_init; + nd_pmu->pmu.add = nd_pmu->add; + nd_pmu->pmu.del = nd_pmu->del; + nd_pmu->pmu.read = nd_pmu->read; + + nd_pmu->pmu.attr_groups = nd_pmu->attr_groups; + nd_pmu->pmu.capabilities = PERF_PMU_CAP_NO_INTERRUPT | + PERF_PMU_CAP_NO_EXCLUDE; + + /* + * Add platform_device->dev pointer to nvdimm_pmu to access + * device data in events functions. + */ + nd_pmu->dev = &pdev->dev; + + if (!nd_pmu->attr_groups[NVDIMM_PMU_CPUMASK_ATTR]) { + /* init cpuhotplug */ + rc = nvdimm_pmu_cpu_hotplug_init(nd_pmu); + if (rc) { + pr_info("cpu hotplug feature failed for device: %s\n", nd_pmu->name); + return rc; + } + } + + rc = perf_pmu_register(&nd_pmu->pmu, nd_pmu->name, -1); + if (rc) { + nvdimm_pmu_free_hotplug_memory(nd_pmu); + return rc; + } + + pr_info("%s NVDIMM performance monitor support registered\n", + nd_pmu->name); + + return 0; +} +EXPORT_SYMBOL_GPL(register_nvdimm_pmu); + +void unregister_nvdimm_pmu(struct nvdimm_pmu *nd_pmu) +{ + + /* handle freeing of memory nd_pmu in arch specific code */ + perf_pmu_unregister(&nd_pmu->pmu); + nvdimm_pmu_free_hotplug_memory(nd_pmu); +} +EXPORT_SYMBOL_GPL(unregister_nvdimm_pmu); diff --git a/include/linux/nd.h b/include/linux/nd.h index 3baeeb7c3c41..f71744daa234 100644 --- a/include/linux/nd.h +++ b/include/linux/nd.h @@ -62,6 +62,9 @@ struct nvdimm_pmu { enum cpuhp_state cpuhp_state; }; +int register_nvdimm_pmu(struct nvdimm_pmu *nvdimm, struct platform_device *pdev); +void unregister_nvdimm_pmu(struct nvdimm_pmu *nd_pmu); + struct nd_device_driver { struct device_driver drv; unsigned long type; -- 2.27.0
|  |