[GIT PULL] perf events fixes

From: Ingo Molnar
Date: Wed Sep 08 2010 - 09:00:41 EST

Linus,

Please pull the latest perf-fixes-for-linus git tree from:

git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip.git perf-fixes-for-linus

Thanks,

Ingo

------------------>
Don Zickus (2):
lockup_detector: Sync touch_*_watchdog back to old semantics
perf, x86: Fix accidentally ack'ing a second event on intel perf counter

Frederic Weisbecker (1):
perf: Initialize callchains roots's childen hits

Li Zefan (1):
tracing: Fix a race in function profile

Peter Zijlstra (1):
perf, x86: Fix handle_irq return values

Robert Richter (4):
oprofile: fix crash when accessing freed task structs
oprofile, x86: fix init_sysfs error handling
oprofile, x86: fix init_sysfs() function stub
perf, x86: Try to handle unknown nmis with an enabled PMU

Stephane Eranian (1):
perf_events: Fix time tracking for events with pid != -1 and cpu != -1


arch/x86/kernel/cpu/perf_event.c | 59 +++++++++++++++++++++++++-------
arch/x86/kernel/cpu/perf_event_intel.c | 15 +++++---
arch/x86/kernel/cpu/perf_event_p4.c | 2 +-
arch/x86/oprofile/nmi_int.c | 22 +++++++++---
drivers/oprofile/buffer_sync.c | 27 +++++++-------
drivers/oprofile/cpu_buffer.c | 2 -
kernel/perf_event.c | 26 ++++++++++++--
kernel/trace/ftrace.c | 15 ++++++--
kernel/watchdog.c | 17 ++++++---
tools/perf/util/callchain.h | 1 +
10 files changed, 133 insertions(+), 53 deletions(-)

diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c
index f2da20f..3efdf28 100644
--- a/arch/x86/kernel/cpu/perf_event.c
+++ b/arch/x86/kernel/cpu/perf_event.c
@@ -1154,7 +1154,7 @@ static int x86_pmu_handle_irq(struct pt_regs *regs)
/*
* event overflow
*/
- handled = 1;
+ handled++;
data.period = event->hw.last_period;

if (!x86_perf_event_set_period(event))
@@ -1200,12 +1200,20 @@ void perf_events_lapic_init(void)
apic_write(APIC_LVTPC, APIC_DM_NMI);
}

+struct pmu_nmi_state {
+ unsigned int marked;
+ int handled;
+};
+
+static DEFINE_PER_CPU(struct pmu_nmi_state, pmu_nmi);
+
static int __kprobes
perf_event_nmi_handler(struct notifier_block *self,
unsigned long cmd, void *__args)
{
struct die_args *args = __args;
- struct pt_regs *regs;
+ unsigned int this_nmi;
+ int handled;

if (!atomic_read(&active_events))
return NOTIFY_DONE;
@@ -1214,22 +1222,47 @@ perf_event_nmi_handler(struct notifier_block *self,
case DIE_NMI:
case DIE_NMI_IPI:
break;
-
+ case DIE_NMIUNKNOWN:
+ this_nmi = percpu_read(irq_stat.__nmi_count);
+ if (this_nmi != __get_cpu_var(pmu_nmi).marked)
+ /* let the kernel handle the unknown nmi */
+ return NOTIFY_DONE;
+ /*
+ * This one is a PMU back-to-back nmi. Two events
+ * trigger 'simultaneously' raising two back-to-back
+ * NMIs. If the first NMI handles both, the latter
+ * will be empty and daze the CPU. So, we drop it to
+ * avoid false-positive 'unknown nmi' messages.
+ */
+ return NOTIFY_STOP;
default:
return NOTIFY_DONE;
}

- regs = args->regs;
-
apic_write(APIC_LVTPC, APIC_DM_NMI);
- /*
- * Can't rely on the handled return value to say it was our NMI, two
- * events could trigger 'simultaneously' raising two back-to-back NMIs.
- *
- * If the first NMI handles both, the latter will be empty and daze
- * the CPU.
- */
- x86_pmu.handle_irq(regs);
+
+ handled = x86_pmu.handle_irq(args->regs);
+ if (!handled)
+ return NOTIFY_DONE;
+
+ this_nmi = percpu_read(irq_stat.__nmi_count);
+ if ((handled > 1) ||
+ /* the next nmi could be a back-to-back nmi */
+ ((__get_cpu_var(pmu_nmi).marked == this_nmi) &&
+ (__get_cpu_var(pmu_nmi).handled > 1))) {
+ /*
+ * We could have two subsequent back-to-back nmis: The
+ * first handles more than one counter, the 2nd
+ * handles only one counter and the 3rd handles no
+ * counter.
+ *
+ * This is the 2nd nmi because the previous was
+ * handling more than one counter. We will mark the
+ * next (3rd) and then drop it if unhandled.
+ */
+ __get_cpu_var(pmu_nmi).marked = this_nmi + 1;
+ __get_cpu_var(pmu_nmi).handled = handled;
+ }

return NOTIFY_STOP;
}
diff --git a/arch/x86/kernel/cpu/perf_event_intel.c b/arch/x86/kernel/cpu/perf_event_intel.c
index d8d86d0..ee05c90 100644
--- a/arch/x86/kernel/cpu/perf_event_intel.c
+++ b/arch/x86/kernel/cpu/perf_event_intel.c
@@ -712,7 +712,8 @@ static int intel_pmu_handle_irq(struct pt_regs *regs)
struct perf_sample_data data;
struct cpu_hw_events *cpuc;
int bit, loops;
- u64 ack, status;
+ u64 status;
+ int handled = 0;

perf_sample_data_init(&data, 0);

@@ -728,6 +729,7 @@ static int intel_pmu_handle_irq(struct pt_regs *regs)

loops = 0;
again:
+ intel_pmu_ack_status(status);
if (++loops > 100) {
WARN_ONCE(1, "perfevents: irq loop stuck!\n");
perf_event_print_debug();
@@ -736,19 +738,22 @@ again:
}

inc_irq_stat(apic_perf_irqs);
- ack = status;

intel_pmu_lbr_read();

/*
* PEBS overflow sets bit 62 in the global status register
*/
- if (__test_and_clear_bit(62, (unsigned long *)&status))
+ if (__test_and_clear_bit(62, (unsigned long *)&status)) {
+ handled++;
x86_pmu.drain_pebs(regs);
+ }

for_each_set_bit(bit, (unsigned long *)&status, X86_PMC_IDX_MAX) {
struct perf_event *event = cpuc->events[bit];

+ handled++;
+
if (!test_bit(bit, cpuc->active_mask))
continue;

@@ -761,8 +766,6 @@ again:
x86_pmu_stop(event);
}

- intel_pmu_ack_status(ack);
-
/*
* Repeat if there is more work to be done:
*/
@@ -772,7 +775,7 @@ again:

done:
intel_pmu_enable_all(0);
- return 1;
+ return handled;
}

static struct event_constraint *
diff --git a/arch/x86/kernel/cpu/perf_event_p4.c b/arch/x86/kernel/cpu/perf_event_p4.c
index 7e578e9..b560db3 100644
--- a/arch/x86/kernel/cpu/perf_event_p4.c
+++ b/arch/x86/kernel/cpu/perf_event_p4.c
@@ -692,7 +692,7 @@ static int p4_pmu_handle_irq(struct pt_regs *regs)
inc_irq_stat(apic_perf_irqs);
}

- return handled > 0;
+ return handled;
}

/*
diff --git a/arch/x86/oprofile/nmi_int.c b/arch/x86/oprofile/nmi_int.c
index f6b48f6..cfe4faa 100644
--- a/arch/x86/oprofile/nmi_int.c
+++ b/arch/x86/oprofile/nmi_int.c
@@ -568,8 +568,13 @@ static int __init init_sysfs(void)
int error;

error = sysdev_class_register(&oprofile_sysclass);
- if (!error)
- error = sysdev_register(&device_oprofile);
+ if (error)
+ return error;
+
+ error = sysdev_register(&device_oprofile);
+ if (error)
+ sysdev_class_unregister(&oprofile_sysclass);
+
return error;
}

@@ -580,8 +585,10 @@ static void exit_sysfs(void)
}

#else
-#define init_sysfs() do { } while (0)
-#define exit_sysfs() do { } while (0)
+
+static inline int init_sysfs(void) { return 0; }
+static inline void exit_sysfs(void) { }
+
#endif /* CONFIG_PM */

static int __init p4_init(char **cpu_type)
@@ -695,6 +702,8 @@ int __init op_nmi_init(struct oprofile_operations *ops)
char *cpu_type = NULL;
int ret = 0;

+ using_nmi = 0;
+
if (!cpu_has_apic)
return -ENODEV;

@@ -774,7 +783,10 @@ int __init op_nmi_init(struct oprofile_operations *ops)

mux_init(ops);

- init_sysfs();
+ ret = init_sysfs();
+ if (ret)
+ return ret;
+
using_nmi = 1;
printk(KERN_INFO "oprofile: using NMI interrupt.\n");
return 0;
diff --git a/drivers/oprofile/buffer_sync.c b/drivers/oprofile/buffer_sync.c
index a9352b2..b7e755f 100644
--- a/drivers/oprofile/buffer_sync.c
+++ b/drivers/oprofile/buffer_sync.c
@@ -141,16 +141,6 @@ static struct notifier_block module_load_nb = {
.notifier_call = module_load_notify,
};

-
-static void end_sync(void)
-{
- end_cpu_work();
- /* make sure we don't leak task structs */
- process_task_mortuary();
- process_task_mortuary();
-}
-
-
int sync_start(void)
{
int err;
@@ -158,7 +148,7 @@ int sync_start(void)
if (!zalloc_cpumask_var(&marked_cpus, GFP_KERNEL))
return -ENOMEM;

- start_cpu_work();
+ mutex_lock(&buffer_mutex);

err = task_handoff_register(&task_free_nb);
if (err)
@@ -173,7 +163,10 @@ int sync_start(void)
if (err)
goto out4;

+ start_cpu_work();
+
out:
+ mutex_unlock(&buffer_mutex);
return err;
out4:
profile_event_unregister(PROFILE_MUNMAP, &munmap_nb);
@@ -182,7 +175,6 @@ out3:
out2:
task_handoff_unregister(&task_free_nb);
out1:
- end_sync();
free_cpumask_var(marked_cpus);
goto out;
}
@@ -190,11 +182,20 @@ out1:

void sync_stop(void)
{
+ /* flush buffers */
+ mutex_lock(&buffer_mutex);
+ end_cpu_work();
unregister_module_notifier(&module_load_nb);
profile_event_unregister(PROFILE_MUNMAP, &munmap_nb);
profile_event_unregister(PROFILE_TASK_EXIT, &task_exit_nb);
task_handoff_unregister(&task_free_nb);
- end_sync();
+ mutex_unlock(&buffer_mutex);
+ flush_scheduled_work();
+
+ /* make sure we don't leak task structs */
+ process_task_mortuary();
+ process_task_mortuary();
+
free_cpumask_var(marked_cpus);
}

diff --git a/drivers/oprofile/cpu_buffer.c b/drivers/oprofile/cpu_buffer.c
index 219f79e..f179ac2 100644
--- a/drivers/oprofile/cpu_buffer.c
+++ b/drivers/oprofile/cpu_buffer.c
@@ -120,8 +120,6 @@ void end_cpu_work(void)

cancel_delayed_work(&b->work);
}
-
- flush_scheduled_work();
}

/*
diff --git a/kernel/perf_event.c b/kernel/perf_event.c
index 403d180..657555a 100644
--- a/kernel/perf_event.c
+++ b/kernel/perf_event.c
@@ -402,11 +402,31 @@ static void perf_group_detach(struct perf_event *event)
}
}

+static inline int
+event_filter_match(struct perf_event *event)
+{
+ return event->cpu == -1 || event->cpu == smp_processor_id();
+}
+
static void
event_sched_out(struct perf_event *event,
struct perf_cpu_context *cpuctx,
struct perf_event_context *ctx)
{
+ u64 delta;
+ /*
+ * An event which could not be activated because of
+ * filter mismatch still needs to have its timings
+ * maintained, otherwise bogus information is return
+ * via read() for time_enabled, time_running:
+ */
+ if (event->state == PERF_EVENT_STATE_INACTIVE
+ && !event_filter_match(event)) {
+ delta = ctx->time - event->tstamp_stopped;
+ event->tstamp_running += delta;
+ event->tstamp_stopped = ctx->time;
+ }
+
if (event->state != PERF_EVENT_STATE_ACTIVE)
return;

@@ -432,9 +452,7 @@ group_sched_out(struct perf_event *group_event,
struct perf_event_context *ctx)
{
struct perf_event *event;
-
- if (group_event->state != PERF_EVENT_STATE_ACTIVE)
- return;
+ int state = group_event->state;

event_sched_out(group_event, cpuctx, ctx);

@@ -444,7 +462,7 @@ group_sched_out(struct perf_event *group_event,
list_for_each_entry(event, &group_event->sibling_list, group_entry)
event_sched_out(event, cpuctx, ctx);

- if (group_event->attr.exclusive)
+ if (state == PERF_EVENT_STATE_ACTIVE && group_event->attr.exclusive)
cpuctx->exclusive = 0;
}

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 0d88ce9..7cb1f45 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -381,12 +381,19 @@ static int function_stat_show(struct seq_file *m, void *v)
{
struct ftrace_profile *rec = v;
char str[KSYM_SYMBOL_LEN];
+ int ret = 0;
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
- static DEFINE_MUTEX(mutex);
static struct trace_seq s;
unsigned long long avg;
unsigned long long stddev;
#endif
+ mutex_lock(&ftrace_profile_lock);
+
+ /* we raced with function_profile_reset() */
+ if (unlikely(rec->counter == 0)) {
+ ret = -EBUSY;
+ goto out;
+ }

kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
seq_printf(m, " %-30.30s %10lu", str, rec->counter);
@@ -408,7 +415,6 @@ static int function_stat_show(struct seq_file *m, void *v)
do_div(stddev, (rec->counter - 1) * 1000);
}

- mutex_lock(&mutex);
trace_seq_init(&s);
trace_print_graph_duration(rec->time, &s);
trace_seq_puts(&s, " ");
@@ -416,11 +422,12 @@ static int function_stat_show(struct seq_file *m, void *v)
trace_seq_puts(&s, " ");
trace_print_graph_duration(stddev, &s);
trace_print_seq(m, &s);
- mutex_unlock(&mutex);
#endif
seq_putc(m, '\n');
+out:
+ mutex_unlock(&ftrace_profile_lock);

- return 0;
+ return ret;
}

static void ftrace_profile_reset(struct ftrace_profile_stat *stat)
diff --git a/kernel/watchdog.c b/kernel/watchdog.c
index 0d53c8e..7f9c3c5 100644
--- a/kernel/watchdog.c
+++ b/kernel/watchdog.c
@@ -122,7 +122,7 @@ static void __touch_watchdog(void)

void touch_softlockup_watchdog(void)
{
- __get_cpu_var(watchdog_touch_ts) = 0;
+ __raw_get_cpu_var(watchdog_touch_ts) = 0;
}
EXPORT_SYMBOL(touch_softlockup_watchdog);

@@ -142,7 +142,14 @@ void touch_all_softlockup_watchdogs(void)
#ifdef CONFIG_HARDLOCKUP_DETECTOR
void touch_nmi_watchdog(void)
{
- __get_cpu_var(watchdog_nmi_touch) = true;
+ if (watchdog_enabled) {
+ unsigned cpu;
+
+ for_each_present_cpu(cpu) {
+ if (per_cpu(watchdog_nmi_touch, cpu) != true)
+ per_cpu(watchdog_nmi_touch, cpu) = true;
+ }
+ }
touch_softlockup_watchdog();
}
EXPORT_SYMBOL(touch_nmi_watchdog);
@@ -433,6 +440,9 @@ static int watchdog_enable(int cpu)
wake_up_process(p);
}

+ /* if any cpu succeeds, watchdog is considered enabled for the system */
+ watchdog_enabled = 1;
+
return 0;
}

@@ -455,9 +465,6 @@ static void watchdog_disable(int cpu)
per_cpu(softlockup_watchdog, cpu) = NULL;
kthread_stop(p);
}
-
- /* if any cpu succeeds, watchdog is considered enabled for the system */
- watchdog_enabled = 1;
}

static void watchdog_enable_all_cpus(void)
diff --git a/tools/perf/util/callchain.h b/tools/perf/util/callchain.h
index 624a96c..6de4313 100644
--- a/tools/perf/util/callchain.h
+++ b/tools/perf/util/callchain.h
@@ -50,6 +50,7 @@ static inline void callchain_init(struct callchain_node *node)
INIT_LIST_HEAD(&node->children);
INIT_LIST_HEAD(&node->val);

+ node->children_hit = 0;
node->parent = NULL;
node->hit = 0;
}
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