struct perf_event *event;
uint64_t value;
- event = field->u.perf_counter.e[ctx->cpu];
- event->pmu->read(event);
- value = local64_read(&event->count);
+ event = field->u.perf_counter->e[ctx->cpu];
+ if (likely(event)) {
+ if (unlikely(event->state == PERF_EVENT_STATE_ERROR)) {
+ value = 0;
+ } else {
+ event->pmu->read(event);
+ value = local64_read(&event->count);
+ }
+ } else {
+ /*
+ * Perf chooses not to be clever and not to support enabling a
+ * perf counter before the cpu is brought up. Therefore, we need
+ * to support having events coming (e.g. scheduler events)
+ * before the counter is setup. Write an arbitrary 0 in this
+ * case.
+ */
+ value = 0;
+ }
lib_ring_buffer_align_ctx(ctx, ltt_alignof(value));
chan->ops->event_write(ctx, &value, sizeof(value));
}
static
void lttng_destroy_perf_counter_field(struct lttng_ctx_field *field)
{
- struct perf_event **events = field->u.perf_counter.e;
+ struct perf_event **events = field->u.perf_counter->e;
int cpu;
get_online_cpus();
perf_event_release_kernel(events[cpu]);
put_online_cpus();
#ifdef CONFIG_HOTPLUG_CPU
- unregister_cpu_notifier(&field->u.perf_counter.nb);
+ unregister_cpu_notifier(&field->u.perf_counter->nb);
#endif
kfree(field->event_field.name);
- kfree(field->u.perf_counter.attr);
+ kfree(field->u.perf_counter->attr);
kfree(events);
+ kfree(field->u.perf_counter);
}
#ifdef CONFIG_HOTPLUG_CPU
void *hcpu)
{
unsigned int cpu = (unsigned long) hcpu;
- struct lttng_ctx_field *field =
- container_of(nb, struct lttng_ctx_field, u.perf_counter.nb);
- struct perf_event **events = field->u.perf_counter.e;
- struct perf_event_attr *attr = field->u.perf_counter.attr;
-
+ struct lttng_perf_counter_field *perf_field =
+ container_of(nb, struct lttng_perf_counter_field, nb);
+ struct perf_event **events = perf_field->e;
+ struct perf_event_attr *attr = perf_field->attr;
+ struct perf_event *pevent;
- if (!field->u.perf_counter.hp_enable)
+ if (!perf_field->hp_enable)
return NOTIFY_OK;
switch (action) {
case CPU_ONLINE:
case CPU_ONLINE_FROZEN:
- events[cpu] = perf_event_create_kernel_counter(attr,
+ pevent = perf_event_create_kernel_counter(attr,
cpu, NULL, overflow_callback);
- if (!events[cpu])
+ if (!pevent || IS_ERR(pevent))
return NOTIFY_BAD;
+ if (pevent->state == PERF_EVENT_STATE_ERROR) {
+ perf_event_release_kernel(pevent);
+ return NOTIFY_BAD;
+ }
+ barrier(); /* Create perf counter before setting event */
+ events[cpu] = pevent;
break;
case CPU_UP_CANCELED:
case CPU_UP_CANCELED_FROZEN:
case CPU_DEAD:
case CPU_DEAD_FROZEN:
- perf_event_release_kernel(events[cpu]);
+ pevent = events[cpu];
+ events[cpu] = NULL;
+ barrier(); /* NULLify event before perf counter teardown */
+ perf_event_release_kernel(pevent);
break;
}
return NOTIFY_OK;
struct lttng_ctx **ctx)
{
struct lttng_ctx_field *field;
+ struct lttng_perf_counter_field *perf_field;
struct perf_event **events;
struct perf_event_attr *attr;
int ret;
if (!events)
return -ENOMEM;
- attr = kzalloc(sizeof(*field->u.perf_counter.attr), GFP_KERNEL);
+ attr = kzalloc(sizeof(struct perf_event_attr), GFP_KERNEL);
if (!attr) {
ret = -ENOMEM;
goto error_attr;
attr->pinned = 1;
attr->disabled = 0;
+ perf_field = kzalloc(sizeof(struct lttng_perf_counter_field), GFP_KERNEL);
+ if (!perf_field) {
+ ret = -ENOMEM;
+ goto error_alloc_perf_field;
+ }
+ perf_field->e = events;
+ perf_field->attr = attr;
+
name_alloc = kstrdup(name, GFP_KERNEL);
if (!name_alloc) {
ret = -ENOMEM;
ret = -ENOMEM;
goto append_context_error;
}
+ if (lttng_find_context(*ctx, name_alloc)) {
+ ret = -EEXIST;
+ goto find_error;
+ }
#ifdef CONFIG_HOTPLUG_CPU
- field->u.perf_counter.nb.notifier_call =
+ perf_field->nb.notifier_call =
lttng_perf_counter_cpu_hp_callback;
- field->u.perf_counter.nb.priority = 0;
- register_cpu_notifier(&field->u.perf_counter.nb);
+ perf_field->nb.priority = 0;
+ register_cpu_notifier(&perf_field->nb);
#endif
get_online_cpus();
for_each_online_cpu(cpu) {
events[cpu] = perf_event_create_kernel_counter(attr,
cpu, NULL, overflow_callback);
- if (!events[cpu]) {
+ if (!events[cpu] || IS_ERR(events[cpu])) {
ret = -EINVAL;
goto counter_error;
}
+ if (events[cpu]->state == PERF_EVENT_STATE_ERROR) {
+ ret = -EBUSY;
+ goto counter_busy;
+ }
}
put_online_cpus();
field->event_field.type.u.basic.integer.encoding = lttng_encode_none;
field->get_size = perf_counter_get_size;
field->record = perf_counter_record;
- field->u.perf_counter.e = events;
- field->u.perf_counter.attr = attr;
- field->u.perf_counter.hp_enable = 1;
+ field->u.perf_counter = perf_field;
+ perf_field->hp_enable = 1;
wrapper_vmalloc_sync_all();
return 0;
+counter_busy:
counter_error:
for_each_online_cpu(cpu) {
- if (events[cpu])
+ if (events[cpu] && !IS_ERR(events[cpu]))
perf_event_release_kernel(events[cpu]);
}
put_online_cpus();
#ifdef CONFIG_HOTPLUG_CPU
- unregister_cpu_notifier(&field->u.perf_counter.nb);
+ unregister_cpu_notifier(&perf_field->nb);
#endif
+find_error:
lttng_remove_context_field(ctx, field);
append_context_error:
kfree(name_alloc);
name_alloc_error:
+ kfree(perf_field);
+error_alloc_perf_field:
kfree(attr);
error_attr:
kfree(events);