1 files changed, 145 insertions, 248 deletions

diff --git a/kernel/events/core.c b/kernel/events/core.c
index f641547beb76..3afc68c08433 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -128,7 +128,7 @@ enum event_type_t {
  * perf_sched_events : >0 events exist
  * perf_cgroup_events: >0 per-cpu cgroup events exist on this cpu
  */
-struct jump_label_key perf_sched_events __read_mostly;
+struct jump_label_key_deferred perf_sched_events __read_mostly;
 static DEFINE_PER_CPU(atomic_t, perf_cgroup_events);
 
 static atomic_t nr_mmap_events __read_mostly;
@@ -185,6 +185,9 @@ static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
 static void update_context_time(struct perf_event_context *ctx);
 static u64 perf_event_time(struct perf_event *event);
 
+static void ring_buffer_attach(struct perf_event *event,
+			       struct ring_buffer *rb);
+
 void __weak perf_event_print_debug(void)	{ }
 
 extern __weak const char *perf_pmu_name(void)
@@ -1127,6 +1130,8 @@ event_sched_out(struct perf_event *event,
 	if (!is_software_event(event))
 		cpuctx->active_oncpu--;
 	ctx->nr_active--;
+	if (event->attr.freq && event->attr.sample_freq)
+		ctx->nr_freq--;
 	if (event->attr.exclusive || !cpuctx->active_oncpu)
 		cpuctx->exclusive = 0;
 }
@@ -1322,6 +1327,7 @@ retry:
 	}
 	raw_spin_unlock_irq(&ctx->lock);
 }
+EXPORT_SYMBOL_GPL(perf_event_disable);
 
 static void perf_set_shadow_time(struct perf_event *event,
 				 struct perf_event_context *ctx,
@@ -1403,6 +1409,8 @@ event_sched_in(struct perf_event *event,
 	if (!is_software_event(event))
 		cpuctx->active_oncpu++;
 	ctx->nr_active++;
+	if (event->attr.freq && event->attr.sample_freq)
+		ctx->nr_freq++;
 
 	if (event->attr.exclusive)
 		cpuctx->exclusive = 1;
@@ -1659,8 +1667,7 @@ retry:
  * Note: this works for group members as well as group leaders
  * since the non-leader members' sibling_lists will be empty.
  */
-static void __perf_event_mark_enabled(struct perf_event *event,
-					struct perf_event_context *ctx)
+static void __perf_event_mark_enabled(struct perf_event *event)
 {
 	struct perf_event *sub;
 	u64 tstamp = perf_event_time(event);
@@ -1698,7 +1705,7 @@ static int __perf_event_enable(void *info)
 	 */
 	perf_cgroup_set_timestamp(current, ctx);
 
-	__perf_event_mark_enabled(event, ctx);
+	__perf_event_mark_enabled(event);
 
 	if (!event_filter_match(event)) {
 		if (is_cgroup_event(event))
@@ -1779,7 +1786,7 @@ void perf_event_enable(struct perf_event *event)
 
 retry:
 	if (!ctx->is_active) {
-		__perf_event_mark_enabled(event, ctx);
+		__perf_event_mark_enabled(event);
 		goto out;
 	}
 
@@ -1806,6 +1813,7 @@ retry:
 out:
 	raw_spin_unlock_irq(&ctx->lock);
 }
+EXPORT_SYMBOL_GPL(perf_event_enable);
 
 int perf_event_refresh(struct perf_event *event, int refresh)
 {
@@ -2171,9 +2179,10 @@ static void perf_event_context_sched_in(struct perf_event_context *ctx,
 	 */
 	cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
 
-	perf_event_sched_in(cpuctx, ctx, task);
+	if (ctx->nr_events)
+		cpuctx->task_ctx = ctx;
 
-	cpuctx->task_ctx = ctx;
+	perf_event_sched_in(cpuctx, cpuctx->task_ctx, task);
 
 	perf_pmu_enable(ctx->pmu);
 	perf_ctx_unlock(cpuctx, ctx);
@@ -2323,6 +2332,9 @@ static void perf_ctx_adjust_freq(struct perf_event_context *ctx, u64 period)
 	u64 interrupts, now;
 	s64 delta;
 
+	if (!ctx->nr_freq)
+		return;
+
 	list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
 		if (event->state != PERF_EVENT_STATE_ACTIVE)
 			continue;
@@ -2378,12 +2390,14 @@ static void perf_rotate_context(struct perf_cpu_context *cpuctx)
 {
 	u64 interval = (u64)cpuctx->jiffies_interval * TICK_NSEC;
 	struct perf_event_context *ctx = NULL;
-	int rotate = 0, remove = 1;
+	int rotate = 0, remove = 1, freq = 0;
 
 	if (cpuctx->ctx.nr_events) {
 		remove = 0;
 		if (cpuctx->ctx.nr_events != cpuctx->ctx.nr_active)
 			rotate = 1;
+		if (cpuctx->ctx.nr_freq)
+			freq = 1;
 	}
 
 	ctx = cpuctx->task_ctx;
@@ -2391,33 +2405,40 @@ static void perf_rotate_context(struct perf_cpu_context *cpuctx)
 		remove = 0;
 		if (ctx->nr_events != ctx->nr_active)
 			rotate = 1;
+		if (ctx->nr_freq)
+			freq = 1;
 	}
 
+	if (!rotate && !freq)
+		goto done;
+
 	perf_ctx_lock(cpuctx, cpuctx->task_ctx);
 	perf_pmu_disable(cpuctx->ctx.pmu);
-	perf_ctx_adjust_freq(&cpuctx->ctx, interval);
-	if (ctx)
-		perf_ctx_adjust_freq(ctx, interval);
 
-	if (!rotate)
-		goto done;
+	if (freq) {
+		perf_ctx_adjust_freq(&cpuctx->ctx, interval);
+		if (ctx)
+			perf_ctx_adjust_freq(ctx, interval);
+	}
 
-	cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
-	if (ctx)
-		ctx_sched_out(ctx, cpuctx, EVENT_FLEXIBLE);
+	if (rotate) {
+		cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
+		if (ctx)
+			ctx_sched_out(ctx, cpuctx, EVENT_FLEXIBLE);
 
-	rotate_ctx(&cpuctx->ctx);
-	if (ctx)
-		rotate_ctx(ctx);
+		rotate_ctx(&cpuctx->ctx);
+		if (ctx)
+			rotate_ctx(ctx);
+
+		perf_event_sched_in(cpuctx, ctx, current);
+	}
 
-	perf_event_sched_in(cpuctx, ctx, current);
+	perf_pmu_enable(cpuctx->ctx.pmu);
+	perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
 
 done:
 	if (remove)
 		list_del_init(&cpuctx->rotation_list);
-
-	perf_pmu_enable(cpuctx->ctx.pmu);
-	perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
 }
 
 void perf_event_task_tick(void)
@@ -2444,7 +2465,7 @@ static int event_enable_on_exec(struct perf_event *event,
 	if (event->state >= PERF_EVENT_STATE_INACTIVE)
 		return 0;
 
-	__perf_event_mark_enabled(event, ctx);
+	__perf_event_mark_enabled(event);
 
 	return 1;
 }
@@ -2476,13 +2497,7 @@ static void perf_event_enable_on_exec(struct perf_event_context *ctx)
 	raw_spin_lock(&ctx->lock);
 	task_ctx_sched_out(ctx);
 
-	list_for_each_entry(event, &ctx->pinned_groups, group_entry) {
-		ret = event_enable_on_exec(event, ctx);
-		if (ret)
-			enabled = 1;
-	}
-
-	list_for_each_entry(event, &ctx->flexible_groups, group_entry) {
+	list_for_each_entry(event, &ctx->event_list, event_entry) {
 		ret = event_enable_on_exec(event, ctx);
 		if (ret)
 			enabled = 1;
@@ -2570,215 +2585,6 @@ static u64 perf_event_read(struct perf_event *event)
 }
 
 /*
- * Callchain support
- */
-
-struct callchain_cpus_entries {
-	struct rcu_head			rcu_head;
-	struct perf_callchain_entry	*cpu_entries[0];
-};
-
-static DEFINE_PER_CPU(int, callchain_recursion[PERF_NR_CONTEXTS]);
-static atomic_t nr_callchain_events;
-static DEFINE_MUTEX(callchain_mutex);
-struct callchain_cpus_entries *callchain_cpus_entries;
-
-
-__weak void perf_callchain_kernel(struct perf_callchain_entry *entry,
-				  struct pt_regs *regs)
-{
-}
-
-__weak void perf_callchain_user(struct perf_callchain_entry *entry,
-				struct pt_regs *regs)
-{
-}
-
-static void release_callchain_buffers_rcu(struct rcu_head *head)
-{
-	struct callchain_cpus_entries *entries;
-	int cpu;
-
-	entries = container_of(head, struct callchain_cpus_entries, rcu_head);
-
-	for_each_possible_cpu(cpu)
-		kfree(entries->cpu_entries[cpu]);
-
-	kfree(entries);
-}
-
-static void release_callchain_buffers(void)
-{
-	struct callchain_cpus_entries *entries;
-
-	entries = callchain_cpus_entries;
-	rcu_assign_pointer(callchain_cpus_entries, NULL);
-	call_rcu(&entries->rcu_head, release_callchain_buffers_rcu);
-}
-
-static int alloc_callchain_buffers(void)
-{
-	int cpu;
-	int size;
-	struct callchain_cpus_entries *entries;
-
-	/*
-	 * We can't use the percpu allocation API for data that can be
-	 * accessed from NMI. Use a temporary manual per cpu allocation
-	 * until that gets sorted out.
-	 */
-	size = offsetof(struct callchain_cpus_entries, cpu_entries[nr_cpu_ids]);
-
-	entries = kzalloc(size, GFP_KERNEL);
-	if (!entries)
-		return -ENOMEM;
-
-	size = sizeof(struct perf_callchain_entry) * PERF_NR_CONTEXTS;
-
-	for_each_possible_cpu(cpu) {
-		entries->cpu_entries[cpu] = kmalloc_node(size, GFP_KERNEL,
-							 cpu_to_node(cpu));
-		if (!entries->cpu_entries[cpu])
-			goto fail;
-	}
-
-	rcu_assign_pointer(callchain_cpus_entries, entries);
-
-	return 0;
-
-fail:
-	for_each_possible_cpu(cpu)
-		kfree(entries->cpu_entries[cpu]);
-	kfree(entries);
-
-	return -ENOMEM;
-}
-
-static int get_callchain_buffers(void)
-{
-	int err = 0;
-	int count;
-
-	mutex_lock(&callchain_mutex);
-
-	count = atomic_inc_return(&nr_callchain_events);
-	if (WARN_ON_ONCE(count < 1)) {
-		err = -EINVAL;
-		goto exit;
-	}
-
-	if (count > 1) {
-		/* If the allocation failed, give up */
-		if (!callchain_cpus_entries)
-			err = -ENOMEM;
-		goto exit;
-	}
-
-	err = alloc_callchain_buffers();
-	if (err)
-		release_callchain_buffers();
-exit:
-	mutex_unlock(&callchain_mutex);
-
-	return err;
-}
-
-static void put_callchain_buffers(void)
-{
-	if (atomic_dec_and_mutex_lock(&nr_callchain_events, &callchain_mutex)) {
-		release_callchain_buffers();
-		mutex_unlock(&callchain_mutex);
-	}
-}
-
-static int get_recursion_context(int *recursion)
-{
-	int rctx;
-
-	if (in_nmi())
-		rctx = 3;
-	else if (in_irq())
-		rctx = 2;
-	else if (in_softirq())
-		rctx = 1;
-	else
-		rctx = 0;
-
-	if (recursion[rctx])
-		return -1;
-
-	recursion[rctx]++;
-	barrier();
-
-	return rctx;
-}
-
-static inline void put_recursion_context(int *recursion, int rctx)
-{
-	barrier();
-	recursion[rctx]--;
-}
-
-static struct perf_callchain_entry *get_callchain_entry(int *rctx)
-{
-	int cpu;
-	struct callchain_cpus_entries *entries;
-
-	*rctx = get_recursion_context(__get_cpu_var(callchain_recursion));
-	if (*rctx == -1)
-		return NULL;
-
-	entries = rcu_dereference(callchain_cpus_entries);
-	if (!entries)
-		return NULL;
-
-	cpu = smp_processor_id();
-
-	return &entries->cpu_entries[cpu][*rctx];
-}
-
-static void
-put_callchain_entry(int rctx)
-{
-	put_recursion_context(__get_cpu_var(callchain_recursion), rctx);
-}
-
-static struct perf_callchain_entry *perf_callchain(struct pt_regs *regs)
-{
-	int rctx;
-	struct perf_callchain_entry *entry;
-
-
-	entry = get_callchain_entry(&rctx);
-	if (rctx == -1)
-		return NULL;
-
-	if (!entry)
-		goto exit_put;
-
-	entry->nr = 0;
-
-	if (!user_mode(regs)) {
-		perf_callchain_store(entry, PERF_CONTEXT_KERNEL);
-		perf_callchain_kernel(entry, regs);
-		if (current->mm)
-			regs = task_pt_regs(current);
-		else
-			regs = NULL;
-	}
-
-	if (regs) {
-		perf_callchain_store(entry, PERF_CONTEXT_USER);
-		perf_callchain_user(entry, regs);
-	}
-
-exit_put:
-	put_callchain_entry(rctx);
-
-	return entry;
-}
-
-/*
  * Initialize the perf_event context in a task_struct:
  */
 static void __perf_event_init_context(struct perf_event_context *ctx)
@@ -2942,7 +2748,7 @@ static void free_event(struct perf_event *event)
 
 	if (!event->parent) {
 		if (event->attach_state & PERF_ATTACH_TASK)
-			jump_label_dec(&perf_sched_events);
+			jump_label_dec_deferred(&perf_sched_events);
 		if (event->attr.mmap || event->attr.mmap_data)
 			atomic_dec(&nr_mmap_events);
 		if (event->attr.comm)
@@ -2953,7 +2759,7 @@ static void free_event(struct perf_event *event)
 			put_callchain_buffers();
 		if (is_cgroup_event(event)) {
 			atomic_dec(&per_cpu(perf_cgroup_events, event->cpu));
-			jump_label_dec(&perf_sched_events);
+			jump_label_dec_deferred(&perf_sched_events);
 		}
 	}
 
@@ -3190,12 +2996,33 @@ static unsigned int perf_poll(struct file *file, poll_table *wait)
 	struct ring_buffer *rb;
 	unsigned int events = POLL_HUP;
 
+	/*
+	 * Race between perf_event_set_output() and perf_poll(): perf_poll()
+	 * grabs the rb reference but perf_event_set_output() overrides it.
+	 * Here is the timeline for two threads T1, T2:
+	 * t0: T1, rb = rcu_dereference(event->rb)
+	 * t1: T2, old_rb = event->rb
+	 * t2: T2, event->rb = new rb
+	 * t3: T2, ring_buffer_detach(old_rb)
+	 * t4: T1, ring_buffer_attach(rb1)
+	 * t5: T1, poll_wait(event->waitq)
+	 *
+	 * To avoid this problem, we grab mmap_mutex in perf_poll()
+	 * thereby ensuring that the assignment of the new ring buffer
+	 * and the detachment of the old buffer appear atomic to perf_poll()
+	 */
+	mutex_lock(&event->mmap_mutex);
+
 	rcu_read_lock();
 	rb = rcu_dereference(event->rb);
-	if (rb)
+	if (rb) {
+		ring_buffer_attach(event, rb);
 		events = atomic_xchg(&rb->poll, 0);
+	}
 	rcu_read_unlock();
 
+	mutex_unlock(&event->mmap_mutex);
+
 	poll_wait(file, &event->waitq, wait);
 
 	return events;
@@ -3496,6 +3323,53 @@ unlock:
 	return ret;
 }
 
+static void ring_buffer_attach(struct perf_event *event,
+			       struct ring_buffer *rb)
+{
+	unsigned long flags;
+
+	if (!list_empty(&event->rb_entry))
+		return;
+
+	spin_lock_irqsave(&rb->event_lock, flags);
+	if (!list_empty(&event->rb_entry))
+		goto unlock;
+
+	list_add(&event->rb_entry, &rb->event_list);
+unlock:
+	spin_unlock_irqrestore(&rb->event_lock, flags);
+}
+
+static void ring_buffer_detach(struct perf_event *event,
+			       struct ring_buffer *rb)
+{
+	unsigned long flags;
+
+	if (list_empty(&event->rb_entry))
+		return;
+
+	spin_lock_irqsave(&rb->event_lock, flags);
+	list_del_init(&event->rb_entry);
+	wake_up_all(&event->waitq);
+	spin_unlock_irqrestore(&rb->event_lock, flags);
+}
+
+static void ring_buffer_wakeup(struct perf_event *event)
+{
+	struct ring_buffer *rb;
+
+	rcu_read_lock();
+	rb = rcu_dereference(event->rb);
+	if (!rb)
+		goto unlock;
+
+	list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
+		wake_up_all(&event->waitq);
+
+unlock:
+	rcu_read_unlock();
+}
+
 static void rb_free_rcu(struct rcu_head *rcu_head)
 {
 	struct ring_buffer *rb;
@@ -3521,9 +3395,19 @@ static struct ring_buffer *ring_buffer_get(struct perf_event *event)
 
 static void ring_buffer_put(struct ring_buffer *rb)
 {
+	struct perf_event *event, *n;
+	unsigned long flags;
+
 	if (!atomic_dec_and_test(&rb->refcount))
 		return;
 
+	spin_lock_irqsave(&rb->event_lock, flags);
+	list_for_each_entry_safe(event, n, &rb->event_list, rb_entry) {
+		list_del_init(&event->rb_entry);
+		wake_up_all(&event->waitq);
+	}
+	spin_unlock_irqrestore(&rb->event_lock, flags);
+
 	call_rcu(&rb->rcu_head, rb_free_rcu);
 }
 
@@ -3546,6 +3430,7 @@ static void perf_mmap_close(struct vm_area_struct *vma)
 		atomic_long_sub((size >> PAGE_SHIFT) + 1, &user->locked_vm);
 		vma->vm_mm->pinned_vm -= event->mmap_locked;
 		rcu_assign_pointer(event->rb, NULL);
+		ring_buffer_detach(event, rb);
 		mutex_unlock(&event->mmap_mutex);
 
 		ring_buffer_put(rb);
@@ -3700,7 +3585,7 @@ static const struct file_operations perf_fops = {
 
 void perf_event_wakeup(struct perf_event *event)
 {
-	wake_up_all(&event->waitq);
+	ring_buffer_wakeup(event);
 
 	if (event->pending_kill) {
 		kill_fasync(&event->fasync, SIGIO, event->pending_kill);
@@ -4737,7 +4622,6 @@ static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
 	struct hw_perf_event *hwc = &event->hw;
 	int throttle = 0;
 
-	data->period = event->hw.last_period;
 	if (!overflow)
 		overflow = perf_swevent_set_period(event);
 
@@ -4771,6 +4655,12 @@ static void perf_swevent_event(struct perf_event *event, u64 nr,
 	if (!is_sampling_event(event))
 		return;
 
+	if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) {
+		data->period = nr;
+		return perf_swevent_overflow(event, 1, data, regs);
+	} else
+		data->period = event->hw.last_period;
+
 	if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
 		return perf_swevent_overflow(event, 1, data, regs);
 
@@ -5283,7 +5173,7 @@ static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
 	regs = get_irq_regs();
 
 	if (regs && !perf_exclude_event(event, regs)) {
-		if (!(event->attr.exclude_idle && current->pid == 0))
+		if (!(event->attr.exclude_idle && is_idle_task(current)))
 			if (perf_event_overflow(event, &data, regs))
 				ret = HRTIMER_NORESTART;
 	}
@@ -5822,6 +5712,8 @@ perf_event_alloc(struct perf_event_attr *attr, int cpu,
 	INIT_LIST_HEAD(&event->group_entry);
 	INIT_LIST_HEAD(&event->event_entry);
 	INIT_LIST_HEAD(&event->sibling_list);
+	INIT_LIST_HEAD(&event->rb_entry);
+
 	init_waitqueue_head(&event->waitq);
 	init_irq_work(&event->pending, perf_pending_event);
 
@@ -5896,7 +5788,7 @@ done:
 
 	if (!event->parent) {
 		if (event->attach_state & PERF_ATTACH_TASK)
-			jump_label_inc(&perf_sched_events);
+			jump_label_inc(&perf_sched_events.key);
 		if (event->attr.mmap || event->attr.mmap_data)
 			atomic_inc(&nr_mmap_events);
 		if (event->attr.comm)
@@ -6028,6 +5920,8 @@ set:
 
 	old_rb = event->rb;
 	rcu_assign_pointer(event->rb, rb);
+	if (old_rb)
+		ring_buffer_detach(event, old_rb);
 	ret = 0;
 unlock:
 	mutex_unlock(&event->mmap_mutex);
@@ -6132,7 +6026,7 @@ SYSCALL_DEFINE5(perf_event_open,
 		 * - that may need work on context switch
 		 */
 		atomic_inc(&per_cpu(perf_cgroup_events, event->cpu));
-		jump_label_inc(&perf_sched_events);
+		jump_label_inc(&perf_sched_events.key);
 	}
 
 	/*
@@ -6978,6 +6872,9 @@ void __init perf_event_init(void)
 
 	ret = init_hw_breakpoint();
 	WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
+
+	/* do not patch jump label more than once per second */
+	jump_label_rate_limit(&perf_sched_events, HZ);
 }
 
 static int __init perf_event_sysfs_init(void)