---

yaml
---
r: 205232
b: refs/heads/master
c: 761844b
h: refs/heads/master
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 6113e45f831616de98c54a005260223b21bcb6b9
+refs/heads/master: 761844b9c68b3c67b085265f92ac0675706cc3b3

trunk/arch/powerpc/oprofile/op_model_cell.c

@@ -1077,7 +1077,7 @@ static int calculate_lfsr(int n)
 		index = ENTRIES-1;
 
 	/* make sure index is valid */
-	if ((index >= ENTRIES) || (index < 0))
+	if ((index > ENTRIES) || (index < 0))
 		index = ENTRIES-1;
 
 	return initial_lfsr[index];

trunk/kernel/perf_event.c

@@ -1507,9 +1507,6 @@ do {					\
 		divisor = nsec * frequency;
 	}
 
-	if (!divisor)
-		return dividend;
-
 	return div64_u64(dividend, divisor);
 }
 
@@ -1532,7 +1529,7 @@ static int perf_event_start(struct perf_event *event)
 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count)
 {
 	struct hw_perf_event *hwc = &event->hw;
-	s64 period, sample_period;
+	u64 period, sample_period;
 	s64 delta;
 
 	period = perf_calculate_period(event, nsec, count);

trunk/kernel/sched.c

@@ -3730,7 +3730,7 @@ int mutex_spin_on_owner(struct mutex *lock, struct thread_info *owner)
  * off of preempt_enable. Kernel preemptions off return from interrupt
  * occur there and call schedule directly.
  */
-asmlinkage void __sched notrace preempt_schedule(void)
+asmlinkage void __sched preempt_schedule(void)
 {
 	struct thread_info *ti = current_thread_info();
 
@@ -3742,9 +3742,9 @@ asmlinkage void __sched notrace preempt_schedule(void)
 		return;
 
 	do {
-		add_preempt_count_notrace(PREEMPT_ACTIVE);
+		add_preempt_count(PREEMPT_ACTIVE);
 		schedule();
-		sub_preempt_count_notrace(PREEMPT_ACTIVE);
+		sub_preempt_count(PREEMPT_ACTIVE);
 
 		/*
 		 * Check again in case we missed a preemption opportunity

trunk/kernel/trace/ftrace.c

@@ -1883,6 +1883,7 @@ function_trace_probe_call(unsigned long ip, unsigned long parent_ip)
 	struct hlist_head *hhd;
 	struct hlist_node *n;
 	unsigned long key;
+	int resched;
 
 	key = hash_long(ip, FTRACE_HASH_BITS);
 
@@ -1896,12 +1897,12 @@ function_trace_probe_call(unsigned long ip, unsigned long parent_ip)
 	 * period. This syncs the hash iteration and freeing of items
 	 * on the hash. rcu_read_lock is too dangerous here.
 	 */
-	preempt_disable_notrace();
+	resched = ftrace_preempt_disable();
 	hlist_for_each_entry_rcu(entry, n, hhd, node) {
 		if (entry->ip == ip)
 			entry->ops->func(ip, parent_ip, &entry->data);
 	}
-	preempt_enable_notrace();
+	ftrace_preempt_enable(resched);
 }
 
 static struct ftrace_ops trace_probe_ops __read_mostly =

trunk/kernel/trace/ring_buffer.c

@@ -2242,6 +2242,8 @@ static void trace_recursive_unlock(void)
 
 #endif
 
+static DEFINE_PER_CPU(int, rb_need_resched);
+
 /**
  * ring_buffer_lock_reserve - reserve a part of the buffer
  * @buffer: the ring buffer to reserve from
@@ -2262,13 +2264,13 @@ ring_buffer_lock_reserve(struct ring_buffer *buffer, unsigned long length)
 {
 	struct ring_buffer_per_cpu *cpu_buffer;
 	struct ring_buffer_event *event;
-	int cpu;
+	int cpu, resched;
 
 	if (ring_buffer_flags != RB_BUFFERS_ON)
 		return NULL;
 
 	/* If we are tracing schedule, we don't want to recurse */
-	preempt_disable_notrace();
+	resched = ftrace_preempt_disable();
 
 	if (atomic_read(&buffer->record_disabled))
 		goto out_nocheck;
@@ -2293,13 +2295,21 @@ ring_buffer_lock_reserve(struct ring_buffer *buffer, unsigned long length)
 	if (!event)
 		goto out;
 
+	/*
+	 * Need to store resched state on this cpu.
+	 * Only the first needs to.
+	 */
+
+	if (preempt_count() == 1)
+		per_cpu(rb_need_resched, cpu) = resched;
+
 	return event;
 
  out:
 	trace_recursive_unlock();
 
  out_nocheck:
-	preempt_enable_notrace();
+	ftrace_preempt_enable(resched);
 	return NULL;
 }
 EXPORT_SYMBOL_GPL(ring_buffer_lock_reserve);
@@ -2345,7 +2355,13 @@ int ring_buffer_unlock_commit(struct ring_buffer *buffer,
 
 	trace_recursive_unlock();
 
-	preempt_enable_notrace();
+	/*
+	 * Only the last preempt count needs to restore preemption.
+	 */
+	if (preempt_count() == 1)
+		ftrace_preempt_enable(per_cpu(rb_need_resched, cpu));
+	else
+		preempt_enable_no_resched_notrace();
 
 	return 0;
 }
@@ -2453,7 +2469,13 @@ void ring_buffer_discard_commit(struct ring_buffer *buffer,
 
 	trace_recursive_unlock();
 
-	preempt_enable_notrace();
+	/*
+	 * Only the last preempt count needs to restore preemption.
+	 */
+	if (preempt_count() == 1)
+		ftrace_preempt_enable(per_cpu(rb_need_resched, cpu));
+	else
+		preempt_enable_no_resched_notrace();
 
 }
 EXPORT_SYMBOL_GPL(ring_buffer_discard_commit);
@@ -2479,12 +2501,12 @@ int ring_buffer_write(struct ring_buffer *buffer,
 	struct ring_buffer_event *event;
 	void *body;
 	int ret = -EBUSY;
-	int cpu;
+	int cpu, resched;
 
 	if (ring_buffer_flags != RB_BUFFERS_ON)
 		return -EBUSY;
 
-	preempt_disable_notrace();
+	resched = ftrace_preempt_disable();
 
 	if (atomic_read(&buffer->record_disabled))
 		goto out;
@@ -2514,7 +2536,7 @@ int ring_buffer_write(struct ring_buffer *buffer,
 
 	ret = 0;
  out:
-	preempt_enable_notrace();
+	ftrace_preempt_enable(resched);
 
 	return ret;
 }

trunk/kernel/trace/trace.c

@@ -1404,6 +1404,7 @@ int trace_vbprintk(unsigned long ip, const char *fmt, va_list args)
 	struct bprint_entry *entry;
 	unsigned long flags;
 	int disable;
+	int resched;
 	int cpu, len = 0, size, pc;
 
 	if (unlikely(tracing_selftest_running || tracing_disabled))
@@ -1413,7 +1414,7 @@ int trace_vbprintk(unsigned long ip, const char *fmt, va_list args)
 	pause_graph_tracing();
 
 	pc = preempt_count();
-	preempt_disable_notrace();
+	resched = ftrace_preempt_disable();
 	cpu = raw_smp_processor_id();
 	data = tr->data[cpu];
 
@@ -1451,7 +1452,7 @@ int trace_vbprintk(unsigned long ip, const char *fmt, va_list args)
 
 out:
 	atomic_dec_return(&data->disabled);
-	preempt_enable_notrace();
+	ftrace_preempt_enable(resched);
 	unpause_graph_tracing();
 
 	return len;

trunk/kernel/trace/trace.h

@@ -628,6 +628,54 @@ enum trace_iterator_flags {
 
 extern struct tracer nop_trace;
 
+/**
+ * ftrace_preempt_disable - disable preemption scheduler safe
+ *
+ * When tracing can happen inside the scheduler, there exists
+ * cases that the tracing might happen before the need_resched
+ * flag is checked. If this happens and the tracer calls
+ * preempt_enable (after a disable), a schedule might take place
+ * causing an infinite recursion.
+ *
+ * To prevent this, we read the need_resched flag before
+ * disabling preemption. When we want to enable preemption we
+ * check the flag, if it is set, then we call preempt_enable_no_resched.
+ * Otherwise, we call preempt_enable.
+ *
+ * The rational for doing the above is that if need_resched is set
+ * and we have yet to reschedule, we are either in an atomic location
+ * (where we do not need to check for scheduling) or we are inside
+ * the scheduler and do not want to resched.
+ */
+static inline int ftrace_preempt_disable(void)
+{
+	int resched;
+
+	resched = need_resched();
+	preempt_disable_notrace();
+
+	return resched;
+}
+
+/**
+ * ftrace_preempt_enable - enable preemption scheduler safe
+ * @resched: the return value from ftrace_preempt_disable
+ *
+ * This is a scheduler safe way to enable preemption and not miss
+ * any preemption checks. The disabled saved the state of preemption.
+ * If resched is set, then we are either inside an atomic or
+ * are inside the scheduler (we would have already scheduled
+ * otherwise). In this case, we do not want to call normal
+ * preempt_enable, but preempt_enable_no_resched instead.
+ */
+static inline void ftrace_preempt_enable(int resched)
+{
+	if (resched)
+		preempt_enable_no_resched_notrace();
+	else
+		preempt_enable_notrace();
+}
+
 #ifdef CONFIG_BRANCH_TRACER
 extern int enable_branch_tracing(struct trace_array *tr);
 extern void disable_branch_tracing(void);

trunk/kernel/trace/trace_clock.c

@@ -32,15 +32,16 @@
 u64 notrace trace_clock_local(void)
 {
 	u64 clock;
+	int resched;
 
 	/*
 	 * sched_clock() is an architecture implemented, fast, scalable,
 	 * lockless clock. It is not guaranteed to be coherent across
 	 * CPUs, nor across CPU idle events.
 	 */
-	preempt_disable_notrace();
+	resched = ftrace_preempt_disable();
 	clock = sched_clock();
-	preempt_enable_notrace();
+	ftrace_preempt_enable(resched);
 
 	return clock;
 }

trunk/kernel/trace/trace_events.c

@@ -1524,11 +1524,12 @@ function_test_events_call(unsigned long ip, unsigned long parent_ip)
 	struct ftrace_entry *entry;
 	unsigned long flags;
 	long disabled;
+	int resched;
 	int cpu;
 	int pc;
 
 	pc = preempt_count();
-	preempt_disable_notrace();
+	resched = ftrace_preempt_disable();
 	cpu = raw_smp_processor_id();
 	disabled = atomic_inc_return(&per_cpu(ftrace_test_event_disable, cpu));
 
@@ -1550,7 +1551,7 @@ function_test_events_call(unsigned long ip, unsigned long parent_ip)
 
  out:
 	atomic_dec(&per_cpu(ftrace_test_event_disable, cpu));
-	preempt_enable_notrace();
+	ftrace_preempt_enable(resched);
 }
 
 static struct ftrace_ops trace_ops __initdata  =

trunk/kernel/trace/trace_functions.c

@@ -54,14 +54,14 @@ function_trace_call_preempt_only(unsigned long ip, unsigned long parent_ip)
 	struct trace_array_cpu *data;
 	unsigned long flags;
 	long disabled;
-	int cpu;
+	int cpu, resched;
 	int pc;
 
 	if (unlikely(!ftrace_function_enabled))
 		return;
 
 	pc = preempt_count();
-	preempt_disable_notrace();
+	resched = ftrace_preempt_disable();
 	local_save_flags(flags);
 	cpu = raw_smp_processor_id();
 	data = tr->data[cpu];
@@ -71,7 +71,7 @@ function_trace_call_preempt_only(unsigned long ip, unsigned long parent_ip)
 		trace_function(tr, ip, parent_ip, flags, pc);
 
 	atomic_dec(&data->disabled);
-	preempt_enable_notrace();
+	ftrace_preempt_enable(resched);
 }
 
 static void

trunk/kernel/trace/trace_sched_wakeup.c

@@ -46,14 +46,15 @@ wakeup_tracer_call(unsigned long ip, unsigned long parent_ip)
 	struct trace_array_cpu *data;
 	unsigned long flags;
 	long disabled;
+	int resched;
 	int cpu;
 	int pc;
 
 	if (likely(!wakeup_task))
 		return;
 
 	pc = preempt_count();
-	preempt_disable_notrace();
+	resched = ftrace_preempt_disable();
 
 	cpu = raw_smp_processor_id();
 	if (cpu != wakeup_current_cpu)
@@ -73,7 +74,7 @@ wakeup_tracer_call(unsigned long ip, unsigned long parent_ip)
  out:
 	atomic_dec(&data->disabled);
  out_enable:
-	preempt_enable_notrace();
+	ftrace_preempt_enable(resched);
 }
 
 static struct ftrace_ops trace_ops __read_mostly =

trunk/kernel/trace/trace_stack.c

@@ -110,12 +110,12 @@ static inline void check_stack(void)
 static void
 stack_trace_call(unsigned long ip, unsigned long parent_ip)
 {
-	int cpu;
+	int cpu, resched;
 
 	if (unlikely(!ftrace_enabled || stack_trace_disabled))
 		return;
 
-	preempt_disable_notrace();
+	resched = ftrace_preempt_disable();
 
 	cpu = raw_smp_processor_id();
 	/* no atomic needed, we only modify this variable by this cpu */
@@ -127,7 +127,7 @@ stack_trace_call(unsigned long ip, unsigned long parent_ip)
  out:
 	per_cpu(trace_active, cpu)--;
 	/* prevent recursion in schedule */
-	preempt_enable_notrace();
+	ftrace_preempt_enable(resched);
 }
 
 static struct ftrace_ops trace_ops __read_mostly =

trunk/tools/perf/builtin-report.c

@@ -157,8 +157,9 @@ static int process_sample_event(event_t *event, struct perf_session *session)
 
 	event__parse_sample(event, session->sample_type, &data);
 
-	dump_printf("(IP, %d): %d/%d: %#Lx period: %Ld\n", event->header.misc,
-		    data.pid, data.tid, data.ip, data.period);
+	dump_printf("(IP, %d): %d/%d: %#Lx period: %Ld cpu:%d\n",
+		    event->header.misc, data.pid, data.tid, data.ip,
+		    data.period, data.cpu);
 
 	if (session->sample_type & PERF_SAMPLE_CALLCHAIN) {
 		unsigned int i;

trunk/tools/perf/util/event.c

@@ -765,7 +765,8 @@ int event__parse_sample(event_t *event, u64 type, struct sample_data *data)
 		u32 *p = (u32 *)array;
 		data->cpu = *p;
 		array++;
-	}
+	} else
+		data->cpu = -1;
 
 	if (type & PERF_SAMPLE_PERIOD) {
 		data->period = *array;