On 2025-01-16 5:24 p.m., Lucas De Marchi wrote:
> Since commit 4ba4f1afb6a9 ("perf: Generic hotplug support for a PMU with
> a scope"), there's generic support for system-wide counters and
> integration with cpu hotplug. Set our scope to PERF_PMU_SCOPE_SYS_WIDE
> instead of all the boilerplate code for handling hotplug.
>
> Cc: Kan Liang <kan.li...@linux.intel.com>
> Cc: Peter Zijlstra (Intel) <pet...@infradead.org>
> Cc: Vinay Belgaumkar <vinay.belgaum...@intel.com>
> Signed-off-by: Lucas De Marchi <lucas.demar...@intel.com>
> ---
> drivers/gpu/drm/i915/i915_module.c | 2 -
> drivers/gpu/drm/i915/i915_pmu.c | 114 +----------------------------
> drivers/gpu/drm/i915/i915_pmu.h | 11 ---
> 3 files changed, 1 insertion(+), 126 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_module.c
> b/drivers/gpu/drm/i915/i915_module.c
> index 7ed6d70389af9..7affe07f84f45 100644
> --- a/drivers/gpu/drm/i915/i915_module.c
> +++ b/drivers/gpu/drm/i915/i915_module.c
> @@ -71,8 +71,6 @@ static const struct {
> { .init = i915_vma_resource_module_init,
> .exit = i915_vma_resource_module_exit },
> { .init = i915_mock_selftests },
> - { .init = i915_pmu_init,
> - .exit = i915_pmu_exit },
> { .init = i915_pci_register_driver,
> .exit = i915_pci_unregister_driver },
> { .init = i915_perf_sysctl_register,
> diff --git a/drivers/gpu/drm/i915/i915_pmu.c b/drivers/gpu/drm/i915/i915_pmu.c
> index e55db036be1bb..652964ef0643c 100644
> --- a/drivers/gpu/drm/i915/i915_pmu.c
> +++ b/drivers/gpu/drm/i915/i915_pmu.c
> @@ -28,9 +28,6 @@
> BIT(I915_SAMPLE_WAIT) | \
> BIT(I915_SAMPLE_SEMA))
>
> -static cpumask_t i915_pmu_cpumask;
> -static unsigned int i915_pmu_target_cpu = -1;
> -
> static struct i915_pmu *event_to_pmu(struct perf_event *event)
> {
> return container_of(event->pmu, struct i915_pmu, base);
> @@ -642,10 +639,6 @@ static int i915_pmu_event_init(struct perf_event *event)
> if (event->cpu < 0)
> return -EINVAL;
>
> - /* only allow running on one cpu at a time */
> - if (!cpumask_test_cpu(event->cpu, &i915_pmu_cpumask))
> - return -EINVAL;
> -
> if (is_engine_event(event))
> ret = engine_event_init(event);
> else
> @@ -940,23 +933,6 @@ static ssize_t i915_pmu_event_show(struct device *dev,
> return sprintf(buf, "config=0x%lx\n", eattr->val);
> }
>
> -static ssize_t cpumask_show(struct device *dev,
> - struct device_attribute *attr, char *buf)
> -{
> - return cpumap_print_to_pagebuf(true, buf, &i915_pmu_cpumask);
> -}
> -
> -static DEVICE_ATTR_RO(cpumask);
> -
> -static struct attribute *i915_cpumask_attrs[] = {
> - &dev_attr_cpumask.attr,
> - NULL,
> -};
> -
> -static const struct attribute_group i915_pmu_cpumask_attr_group = {
> - .attrs = i915_cpumask_attrs,
> -};
> -
> #define __event(__counter, __name, __unit) \
> { \
> .counter = (__counter), \
> @@ -1173,92 +1149,12 @@ static void free_event_attributes(struct i915_pmu
> *pmu)
> pmu->pmu_attr = NULL;
> }
>
> -static int i915_pmu_cpu_online(unsigned int cpu, struct hlist_node *node)
> -{
> - struct i915_pmu *pmu = hlist_entry_safe(node, typeof(*pmu), cpuhp.node);
> -
> - /* Select the first online CPU as a designated reader. */
> - if (cpumask_empty(&i915_pmu_cpumask))
> - cpumask_set_cpu(cpu, &i915_pmu_cpumask);
> -
> - return 0;
> -}
> -
> -static int i915_pmu_cpu_offline(unsigned int cpu, struct hlist_node *node)
> -{
> - struct i915_pmu *pmu = hlist_entry_safe(node, typeof(*pmu), cpuhp.node);
> - unsigned int target = i915_pmu_target_cpu;
> -
> - /*
> - * Unregistering an instance generates a CPU offline event which we must
> - * ignore to avoid incorrectly modifying the shared i915_pmu_cpumask.
> - */
> - if (!pmu->registered)
> - return 0;
> -
> - if (cpumask_test_and_clear_cpu(cpu, &i915_pmu_cpumask)) {
> - target = cpumask_any_but(topology_sibling_cpumask(cpu), cpu);
> -
I'm not familar with the i915 PMU, but it seems suggest a core scope
PMU, not a system-wide scope.
Thanks,
Kan
> - /* Migrate events if there is a valid target */
> - if (target < nr_cpu_ids) {
> - cpumask_set_cpu(target, &i915_pmu_cpumask);
> - i915_pmu_target_cpu = target;
> - }
> - }
> -
> - if (target < nr_cpu_ids && target != pmu->cpuhp.cpu) {
> - perf_pmu_migrate_context(&pmu->base, cpu, target);
> - pmu->cpuhp.cpu = target;
> - }
> -
> - return 0;
> -}
> -
> -static enum cpuhp_state cpuhp_state = CPUHP_INVALID;
> -
> -int i915_pmu_init(void)
> -{
> - int ret;
> -
> - ret = cpuhp_setup_state_multi(CPUHP_AP_ONLINE_DYN,
> - "perf/x86/intel/i915:online",
> - i915_pmu_cpu_online,
> - i915_pmu_cpu_offline);
> - if (ret < 0)
> - pr_notice("Failed to setup cpuhp state for i915 PMU! (%d)\n",
> - ret);
> - else
> - cpuhp_state = ret;
> -
> - return 0;
> -}
> -
> -void i915_pmu_exit(void)
> -{
> - if (cpuhp_state != CPUHP_INVALID)
> - cpuhp_remove_multi_state(cpuhp_state);
> -}
> -
> -static int i915_pmu_register_cpuhp_state(struct i915_pmu *pmu)
> -{
> - if (cpuhp_state == CPUHP_INVALID)
> - return -EINVAL;
> -
> - return cpuhp_state_add_instance(cpuhp_state, &pmu->cpuhp.node);
> -}
> -
> -static void i915_pmu_unregister_cpuhp_state(struct i915_pmu *pmu)
> -{
> - cpuhp_state_remove_instance(cpuhp_state, &pmu->cpuhp.node);
> -}
> -
> void i915_pmu_register(struct drm_i915_private *i915)
> {
> struct i915_pmu *pmu = &i915->pmu;
> const struct attribute_group *attr_groups[] = {
> &i915_pmu_format_attr_group,
> &pmu->events_attr_group,
> - &i915_pmu_cpumask_attr_group,
> NULL
> };
> int ret = -ENOMEM;
> @@ -1266,7 +1162,6 @@ void i915_pmu_register(struct drm_i915_private *i915)
> spin_lock_init(&pmu->lock);
> hrtimer_init(&pmu->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
> pmu->timer.function = i915_sample;
> - pmu->cpuhp.cpu = -1;
> init_rc6(pmu);
>
> if (IS_DGFX(i915)) {
> @@ -1295,6 +1190,7 @@ void i915_pmu_register(struct drm_i915_private *i915)
>
> pmu->base.module = THIS_MODULE;
> pmu->base.task_ctx_nr = perf_invalid_context;
> + pmu->base.scope = PERF_PMU_SCOPE_SYS_WIDE;
> pmu->base.event_init = i915_pmu_event_init;
> pmu->base.add = i915_pmu_event_add;
> pmu->base.del = i915_pmu_event_del;
> @@ -1307,16 +1203,10 @@ void i915_pmu_register(struct drm_i915_private *i915)
> if (ret)
> goto err_groups;
>
> - ret = i915_pmu_register_cpuhp_state(pmu);
> - if (ret)
> - goto err_unreg;
> -
> pmu->registered = true;
>
> return;
>
> -err_unreg:
> - perf_pmu_unregister(&pmu->base);
> err_groups:
> kfree(pmu->base.attr_groups);
> err_attr:
> @@ -1340,8 +1230,6 @@ void i915_pmu_unregister(struct drm_i915_private *i915)
>
> hrtimer_cancel(&pmu->timer);
>
> - i915_pmu_unregister_cpuhp_state(pmu);
> -
> perf_pmu_unregister(&pmu->base);
> kfree(pmu->base.attr_groups);
> if (IS_DGFX(i915))
> diff --git a/drivers/gpu/drm/i915/i915_pmu.h b/drivers/gpu/drm/i915/i915_pmu.h
> index 8e66d63d0c9f9..53bce3d8bfbaf 100644
> --- a/drivers/gpu/drm/i915/i915_pmu.h
> +++ b/drivers/gpu/drm/i915/i915_pmu.h
> @@ -56,13 +56,6 @@ struct i915_pmu_sample {
> };
>
> struct i915_pmu {
> - /**
> - * @cpuhp: Struct used for CPU hotplug handling.
> - */
> - struct {
> - struct hlist_node node;
> - unsigned int cpu;
> - } cpuhp;
> /**
> * @base: PMU base.
> */
> @@ -155,15 +148,11 @@ struct i915_pmu {
> };
>
> #ifdef CONFIG_PERF_EVENTS
> -int i915_pmu_init(void);
> -void i915_pmu_exit(void);
> void i915_pmu_register(struct drm_i915_private *i915);
> void i915_pmu_unregister(struct drm_i915_private *i915);
> void i915_pmu_gt_parked(struct intel_gt *gt);
> void i915_pmu_gt_unparked(struct intel_gt *gt);
> #else
> -static inline int i915_pmu_init(void) { return 0; }
> -static inline void i915_pmu_exit(void) {}
> static inline void i915_pmu_register(struct drm_i915_private *i915) {}
> static inline void i915_pmu_unregister(struct drm_i915_private *i915) {}
> static inline void i915_pmu_gt_parked(struct intel_gt *gt) {}
