/*
* Performance counter core code
*
- * Copyright(C) 2008 Thomas Gleixner <tglx@linutronix.de>
- * Copyright(C) 2008 Red Hat, Inc., Ingo Molnar
- *
+ * Copyright (C) 2008 Thomas Gleixner <tglx@linutronix.de>
+ * Copyright (C) 2008-2009 Red Hat, Inc., Ingo Molnar
+ * Copyright (C) 2008-2009 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com>
+ * Copyright © 2009 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
*
* For licensing details see kernel-base/COPYING
*/
static atomic_t nr_munmap_tracking __read_mostly;
static atomic_t nr_comm_tracking __read_mostly;
+int sysctl_perf_counter_priv __read_mostly; /* do we need to be privileged */
+
/*
- * Mutex for (sysadmin-configurable) counter reservations:
+ * Lock for (sysadmin-configurable) counter reservations:
*/
-static DEFINE_MUTEX(perf_resource_mutex);
+static DEFINE_SPINLOCK(perf_resource_lock);
/*
* Architecture provided APIs - weak aliases:
*/
-extern __weak const struct hw_perf_counter_ops *
-hw_perf_counter_init(struct perf_counter *counter)
+extern __weak const struct pmu *hw_perf_counter_init(struct perf_counter *counter)
{
return NULL;
}
counter->state = PERF_COUNTER_STATE_INACTIVE;
counter->tstamp_stopped = ctx->time;
- counter->hw_ops->disable(counter);
+ counter->pmu->disable(counter);
counter->oncpu = -1;
if (!is_software_counter(counter))
*/
smp_wmb();
- if (counter->hw_ops->enable(counter)) {
+ if (counter->pmu->enable(counter)) {
counter->state = PERF_COUNTER_STATE_INACTIVE;
counter->oncpu = -1;
return -EAGAIN;
{
struct perf_cpu_context *cpuctx = &per_cpu(perf_cpu_context, cpu);
struct perf_counter_context *ctx = &curr->perf_counter_ctx;
- const int rotate_percpu = 0;
- if (rotate_percpu)
- perf_counter_cpu_sched_out(cpuctx);
+ perf_counter_cpu_sched_out(cpuctx);
perf_counter_task_sched_out(curr, cpu);
- if (rotate_percpu)
- rotate_ctx(&cpuctx->ctx);
+ rotate_ctx(&cpuctx->ctx);
rotate_ctx(ctx);
- if (rotate_percpu)
- perf_counter_cpu_sched_in(cpuctx, cpu);
+ perf_counter_cpu_sched_in(cpuctx, cpu);
perf_counter_task_sched_in(curr, cpu);
}
local_irq_save(flags);
if (ctx->is_active)
update_context_time(ctx);
- counter->hw_ops->read(counter);
+ counter->pmu->read(counter);
update_counter_times(counter);
local_irq_restore(flags);
}
*/
if (cpu != -1) {
/* Must be root to operate on a CPU counter: */
- if (!capable(CAP_SYS_ADMIN))
+ if (sysctl_perf_counter_priv && !capable(CAP_SYS_ADMIN))
return ERR_PTR(-EACCES);
if (cpu < 0 || cpu > num_possible_cpus())
{
struct perf_counter *counter = file->private_data;
struct perf_mmap_data *data;
- unsigned int events;
+ unsigned int events = POLL_HUP;
rcu_read_lock();
data = rcu_dereference(counter->data);
if (data)
- events = atomic_xchg(&data->wakeup, 0);
- else
- events = POLL_HUP;
+ events = atomic_xchg(&data->poll, 0);
rcu_read_unlock();
poll_wait(file, &counter->waitq, wait);
return events;
}
+static void perf_counter_reset(struct perf_counter *counter)
+{
+ atomic_set(&counter->count, 0);
+}
+
static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
struct perf_counter *counter = file->private_data;
case PERF_COUNTER_IOC_REFRESH:
perf_counter_refresh(counter, arg);
break;
+ case PERF_COUNTER_IOC_RESET:
+ perf_counter_reset(counter);
+ break;
default:
err = -ENOTTY;
}
void perf_counter_wakeup(struct perf_counter *counter)
{
- struct perf_mmap_data *data;
-
- rcu_read_lock();
- data = rcu_dereference(counter->data);
- if (data) {
- atomic_set(&data->wakeup, POLL_IN);
- /*
- * Ensure all data writes are issued before updating the
- * user-space data head information. The matching rmb()
- * will be in userspace after reading this value.
- */
- smp_wmb();
- data->user_page->data_head = atomic_read(&data->head);
- }
- rcu_read_unlock();
-
wake_up_all(&counter->waitq);
if (counter->pending_kill) {
struct perf_mmap_data *data;
unsigned int offset;
unsigned int head;
- int wakeup;
int nmi;
int overflow;
+ int locked;
+ unsigned long flags;
};
-static inline void __perf_output_wakeup(struct perf_output_handle *handle)
+static void perf_output_wakeup(struct perf_output_handle *handle)
{
+ atomic_set(&handle->data->poll, POLL_IN);
+
if (handle->nmi) {
handle->counter->pending_wakeup = 1;
perf_pending_queue(&handle->counter->pending,
perf_counter_wakeup(handle->counter);
}
+/*
+ * Curious locking construct.
+ *
+ * We need to ensure a later event doesn't publish a head when a former
+ * event isn't done writing. However since we need to deal with NMIs we
+ * cannot fully serialize things.
+ *
+ * What we do is serialize between CPUs so we only have to deal with NMI
+ * nesting on a single CPU.
+ *
+ * We only publish the head (and generate a wakeup) when the outer-most
+ * event completes.
+ */
+static void perf_output_lock(struct perf_output_handle *handle)
+{
+ struct perf_mmap_data *data = handle->data;
+ int cpu;
+
+ handle->locked = 0;
+
+ local_irq_save(handle->flags);
+ cpu = smp_processor_id();
+
+ if (in_nmi() && atomic_read(&data->lock) == cpu)
+ return;
+
+ while (atomic_cmpxchg(&data->lock, 0, cpu) != 0)
+ cpu_relax();
+
+ handle->locked = 1;
+}
+
+static void perf_output_unlock(struct perf_output_handle *handle)
+{
+ struct perf_mmap_data *data = handle->data;
+ int head, cpu;
+
+ data->done_head = data->head;
+
+ if (!handle->locked)
+ goto out;
+
+again:
+ /*
+ * The xchg implies a full barrier that ensures all writes are done
+ * before we publish the new head, matched by a rmb() in userspace when
+ * reading this position.
+ */
+ while ((head = atomic_xchg(&data->done_head, 0)))
+ data->user_page->data_head = head;
+
+ /*
+ * NMI can happen here, which means we can miss a done_head update.
+ */
+
+ cpu = atomic_xchg(&data->lock, 0);
+ WARN_ON_ONCE(cpu != smp_processor_id());
+
+ /*
+ * Therefore we have to validate we did not indeed do so.
+ */
+ if (unlikely(atomic_read(&data->done_head))) {
+ /*
+ * Since we had it locked, we can lock it again.
+ */
+ while (atomic_cmpxchg(&data->lock, 0, cpu) != 0)
+ cpu_relax();
+
+ goto again;
+ }
+
+ if (atomic_xchg(&data->wakeup, 0))
+ perf_output_wakeup(handle);
+out:
+ local_irq_restore(handle->flags);
+}
+
static int perf_output_begin(struct perf_output_handle *handle,
struct perf_counter *counter, unsigned int size,
int nmi, int overflow)
if (!data)
goto out;
+ handle->data = data;
handle->counter = counter;
handle->nmi = nmi;
handle->overflow = overflow;
if (!data->nr_pages)
goto fail;
+ perf_output_lock(handle);
+
do {
offset = head = atomic_read(&data->head);
head += size;
} while (atomic_cmpxchg(&data->head, offset, head) != offset);
- handle->data = data;
handle->offset = offset;
handle->head = head;
- handle->wakeup = (offset >> PAGE_SHIFT) != (head >> PAGE_SHIFT);
+
+ if ((offset >> PAGE_SHIFT) != (head >> PAGE_SHIFT))
+ atomic_set(&data->wakeup, 1);
return 0;
fail:
- __perf_output_wakeup(handle);
+ perf_output_wakeup(handle);
out:
rcu_read_unlock();
static void perf_output_end(struct perf_output_handle *handle)
{
- int wakeup_events = handle->counter->hw_event.wakeup_events;
+ struct perf_counter *counter = handle->counter;
+ struct perf_mmap_data *data = handle->data;
+
+ int wakeup_events = counter->hw_event.wakeup_events;
if (handle->overflow && wakeup_events) {
- int events = atomic_inc_return(&handle->data->events);
+ int events = atomic_inc_return(&data->events);
if (events >= wakeup_events) {
- atomic_sub(wakeup_events, &handle->data->events);
- __perf_output_wakeup(handle);
+ atomic_sub(wakeup_events, &data->events);
+ atomic_set(&data->wakeup, 1);
}
- } else if (handle->wakeup)
- __perf_output_wakeup(handle);
+ }
+
+ perf_output_unlock(handle);
rcu_read_unlock();
}
leader = counter->group_leader;
list_for_each_entry(sub, &leader->sibling_list, list_entry) {
if (sub != counter)
- sub->hw_ops->read(sub);
+ sub->pmu->read(sub);
group_entry.event = sub->hw_event.config;
group_entry.counter = atomic64_read(&sub->count);
name = strncpy(tmp, "//enomem", sizeof(tmp));
goto got_name;
}
- name = dentry_path(file->f_dentry, buf, PATH_MAX);
+ name = d_path(&file->f_path, buf, PATH_MAX);
if (IS_ERR(name)) {
name = strncpy(tmp, "//toolong", sizeof(tmp));
goto got_name;
struct pt_regs *regs;
counter = container_of(hrtimer, struct perf_counter, hw.hrtimer);
- counter->hw_ops->read(counter);
+ counter->pmu->read(counter);
regs = get_irq_regs();
/*
perf_swcounter_update(counter);
}
-static const struct hw_perf_counter_ops perf_ops_generic = {
+static const struct pmu perf_ops_generic = {
.enable = perf_swcounter_enable,
.disable = perf_swcounter_disable,
.read = perf_swcounter_read,
cpu_clock_perf_counter_update(counter);
}
-static const struct hw_perf_counter_ops perf_ops_cpu_clock = {
+static const struct pmu perf_ops_cpu_clock = {
.enable = cpu_clock_perf_counter_enable,
.disable = cpu_clock_perf_counter_disable,
.read = cpu_clock_perf_counter_read,
task_clock_perf_counter_update(counter, time);
}
-static const struct hw_perf_counter_ops perf_ops_task_clock = {
+static const struct pmu perf_ops_task_clock = {
.enable = task_clock_perf_counter_enable,
.disable = task_clock_perf_counter_disable,
.read = task_clock_perf_counter_read,
cpu_migrations_perf_counter_update(counter);
}
-static const struct hw_perf_counter_ops perf_ops_cpu_migrations = {
+static const struct pmu perf_ops_cpu_migrations = {
.enable = cpu_migrations_perf_counter_enable,
.disable = cpu_migrations_perf_counter_disable,
.read = cpu_migrations_perf_counter_read,
__perf_swcounter_event(PERF_TYPE_TRACEPOINT, event_id, 1, 1, regs, 0);
}
+EXPORT_SYMBOL_GPL(perf_tpcounter_event);
extern int ftrace_profile_enable(int);
extern void ftrace_profile_disable(int);
ftrace_profile_disable(perf_event_id(&counter->hw_event));
}
-static const struct hw_perf_counter_ops *
-tp_perf_counter_init(struct perf_counter *counter)
+static const struct pmu *tp_perf_counter_init(struct perf_counter *counter)
{
int event_id = perf_event_id(&counter->hw_event);
int ret;
return &perf_ops_generic;
}
#else
-static const struct hw_perf_counter_ops *
-tp_perf_counter_init(struct perf_counter *counter)
+static const struct pmu *tp_perf_counter_init(struct perf_counter *counter)
{
return NULL;
}
#endif
-static const struct hw_perf_counter_ops *
-sw_perf_counter_init(struct perf_counter *counter)
+static const struct pmu *sw_perf_counter_init(struct perf_counter *counter)
{
struct perf_counter_hw_event *hw_event = &counter->hw_event;
- const struct hw_perf_counter_ops *hw_ops = NULL;
+ const struct pmu *pmu = NULL;
struct hw_perf_counter *hwc = &counter->hw;
/*
*/
switch (perf_event_id(&counter->hw_event)) {
case PERF_COUNT_CPU_CLOCK:
- hw_ops = &perf_ops_cpu_clock;
+ pmu = &perf_ops_cpu_clock;
if (hw_event->irq_period && hw_event->irq_period < 10000)
hw_event->irq_period = 10000;
* use the cpu_clock counter instead.
*/
if (counter->ctx->task)
- hw_ops = &perf_ops_task_clock;
+ pmu = &perf_ops_task_clock;
else
- hw_ops = &perf_ops_cpu_clock;
+ pmu = &perf_ops_cpu_clock;
if (hw_event->irq_period && hw_event->irq_period < 10000)
hw_event->irq_period = 10000;
case PERF_COUNT_PAGE_FAULTS_MIN:
case PERF_COUNT_PAGE_FAULTS_MAJ:
case PERF_COUNT_CONTEXT_SWITCHES:
- hw_ops = &perf_ops_generic;
+ pmu = &perf_ops_generic;
break;
case PERF_COUNT_CPU_MIGRATIONS:
if (!counter->hw_event.exclude_kernel)
- hw_ops = &perf_ops_cpu_migrations;
+ pmu = &perf_ops_cpu_migrations;
break;
}
- if (hw_ops)
+ if (pmu)
hwc->irq_period = hw_event->irq_period;
- return hw_ops;
+ return pmu;
}
/*
struct perf_counter *group_leader,
gfp_t gfpflags)
{
- const struct hw_perf_counter_ops *hw_ops;
+ const struct pmu *pmu;
struct perf_counter *counter;
long err;
counter->cpu = cpu;
counter->hw_event = *hw_event;
counter->group_leader = group_leader;
- counter->hw_ops = NULL;
+ counter->pmu = NULL;
counter->ctx = ctx;
counter->state = PERF_COUNTER_STATE_INACTIVE;
if (hw_event->disabled)
counter->state = PERF_COUNTER_STATE_OFF;
- hw_ops = NULL;
+ pmu = NULL;
if (perf_event_raw(hw_event)) {
- hw_ops = hw_perf_counter_init(counter);
+ pmu = hw_perf_counter_init(counter);
goto done;
}
switch (perf_event_type(hw_event)) {
case PERF_TYPE_HARDWARE:
- hw_ops = hw_perf_counter_init(counter);
+ pmu = hw_perf_counter_init(counter);
break;
case PERF_TYPE_SOFTWARE:
- hw_ops = sw_perf_counter_init(counter);
+ pmu = sw_perf_counter_init(counter);
break;
case PERF_TYPE_TRACEPOINT:
- hw_ops = tp_perf_counter_init(counter);
+ pmu = tp_perf_counter_init(counter);
break;
}
done:
err = 0;
- if (!hw_ops)
+ if (!pmu)
err = -EINVAL;
- else if (IS_ERR(hw_ops))
- err = PTR_ERR(hw_ops);
+ else if (IS_ERR(pmu))
+ err = PTR_ERR(pmu);
if (err) {
kfree(counter);
return ERR_PTR(err);
}
- counter->hw_ops = hw_ops;
+ counter->pmu = pmu;
if (counter->hw_event.mmap)
atomic_inc(&nr_mmap_tracking);
cpuctx = &per_cpu(perf_cpu_context, cpu);
__perf_counter_init_context(&cpuctx->ctx, NULL);
- mutex_lock(&perf_resource_mutex);
+ spin_lock(&perf_resource_lock);
cpuctx->max_pertask = perf_max_counters - perf_reserved_percpu;
- mutex_unlock(&perf_resource_mutex);
+ spin_unlock(&perf_resource_lock);
hw_perf_counter_setup(cpu);
}
.notifier_call = perf_cpu_notify,
};
-static int __init perf_counter_init(void)
+void __init perf_counter_init(void)
{
perf_cpu_notify(&perf_cpu_nb, (unsigned long)CPU_UP_PREPARE,
(void *)(long)smp_processor_id());
register_cpu_notifier(&perf_cpu_nb);
-
- return 0;
}
-early_initcall(perf_counter_init);
static ssize_t perf_show_reserve_percpu(struct sysdev_class *class, char *buf)
{
if (val > perf_max_counters)
return -EINVAL;
- mutex_lock(&perf_resource_mutex);
+ spin_lock(&perf_resource_lock);
perf_reserved_percpu = val;
for_each_online_cpu(cpu) {
cpuctx = &per_cpu(perf_cpu_context, cpu);
cpuctx->max_pertask = mpt;
spin_unlock_irq(&cpuctx->ctx.lock);
}
- mutex_unlock(&perf_resource_mutex);
+ spin_unlock(&perf_resource_lock);
return count;
}
if (val > 1)
return -EINVAL;
- mutex_lock(&perf_resource_mutex);
+ spin_lock(&perf_resource_lock);
perf_overcommit = val;
- mutex_unlock(&perf_resource_mutex);
+ spin_unlock(&perf_resource_lock);
return count;
}
projects / deliverable / linux.git / blobdiff