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alarmtimer: Add tracepoints for alarm timers 

Alarm timers are one of the mechanisms to wake up a system from suspend,
but there exist no tracepoints to analyse which process/thread armed an
alarmtimer.

Add tracepoints for start/cancel/expire of individual alarm timers and one
for tracing the suspend time decision when to resume the system.

The following trace excerpt illustrates the new mechanism:

Binder:3292_2-3304  [000] d..2   149.981123: alarmtimer_cancel:
alarmtimer:ffffffc1319a7800 type:REALTIME
expires:1325463120000000000 now:1325376810370370245

Binder:3292_2-3304  [000] d..2   149.981136: alarmtimer_start:
alarmtimer:ffffffc1319a7800 type:REALTIME
expires:1325376840000000000 now:1325376810370384591

Binder:3292_9-3953  [000] d..2   150.212991: alarmtimer_cancel:
alarmtimer:ffffffc1319a5a00 type:BOOTTIME
expires:179552000000 now:150154008122

Binder:3292_9-3953  [000] d..2   150.213006: alarmtimer_start:
alarmtimer:ffffffc1319a5a00 type:BOOTTIME
expires:179551000000 now:150154025622

system_server-3000  [002] ...1  162.701940: alarmtimer_suspend:
alarmtimer type:REALTIME expires:1325376840000000000

The wakeup time which is selected at suspend time allows to map it back to
the task arming the timer: Binder:3292_2.

[ tglx: Store alarm timer expiry time instead of some useless RTC relative
  	information, add proper type information for wakeups which are
  	handled via the clock_nanosleep/freezer and massage the changelog. ]

Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Richard Cochran <richardcochran@gmail.com>
Link: http://lkml.kernel.org/r/1480372524-15181-5-git-send-email-john.stultz@linaro.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Baolin Wang 2016-11-28 14:35:21 -08:00 committed by Thomas Gleixner
parent 2924ecd441
commit 4a057549d6
3 changed files with 144 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
include/linux/alarmtimer.h
View File

@ -10,7 +10,12 @@ enum alarmtimer_type {
ALARM_REALTIME,
ALARM_BOOTTIME,
/* Supported types end here */
ALARM_NUMTYPE,
/* Used for tracing information. No usable types. */
ALARM_REALTIME_FREEZER,
ALARM_BOOTTIME_FREEZER,
};
enum alarmtimer_restart {

96
include/trace/events/alarmtimer.h Normal file
View File

@ -0,0 +1,96 @@
#undef TRACE_SYSTEM
#define TRACE_SYSTEM alarmtimer
#if !defined(_TRACE_ALARMTIMER_H) || defined(TRACE_HEADER_MULTI_READ)
#define _TRACE_ALARMTIMER_H
#include <linux/alarmtimer.h>
#include <linux/rtc.h>
#include <linux/tracepoint.h>
TRACE_DEFINE_ENUM(ALARM_REALTIME);
TRACE_DEFINE_ENUM(ALARM_BOOTTIME);
TRACE_DEFINE_ENUM(ALARM_REALTIME_FREEZER);
TRACE_DEFINE_ENUM(ALARM_BOOTTIME_FREEZER);
#define show_alarm_type(type) __print_flags(type, " | ", \
{ 1 << ALARM_REALTIME, "REALTIME" }, \
{ 1 << ALARM_BOOTTIME, "BOOTTIME" }, \
{ 1 << ALARM_REALTIME_FREEZER, "REALTIME Freezer" }, \
{ 1 << ALARM_BOOTTIME_FREEZER, "BOOTTIME Freezer" })
TRACE_EVENT(alarmtimer_suspend,
TP_PROTO(ktime_t expires, int flag),
TP_ARGS(expires, flag),
TP_STRUCT__entry(
__field(s64, expires)
__field(unsigned char, alarm_type)
),
TP_fast_assign(
__entry->expires = expires.tv64;
__entry->alarm_type = flag;
),
TP_printk("alarmtimer type:%s expires:%llu",
show_alarm_type((1 << __entry->alarm_type)),
__entry->expires
)
);
DECLARE_EVENT_CLASS(alarm_class,
TP_PROTO(struct alarm *alarm, ktime_t now),
TP_ARGS(alarm, now),
TP_STRUCT__entry(
__field(void *, alarm)
__field(unsigned char, alarm_type)
__field(s64, expires)
__field(s64, now)
),
TP_fast_assign(
__entry->alarm = alarm;
__entry->alarm_type = alarm->type;
__entry->expires = alarm->node.expires.tv64;
__entry->now = now.tv64;
),
TP_printk("alarmtimer:%p type:%s expires:%llu now:%llu",
__entry->alarm,
show_alarm_type((1 << __entry->alarm_type)),
__entry->expires,
__entry->now
)
);
DEFINE_EVENT(alarm_class, alarmtimer_fired,
TP_PROTO(struct alarm *alarm, ktime_t now),
TP_ARGS(alarm, now)
);
DEFINE_EVENT(alarm_class, alarmtimer_start,
TP_PROTO(struct alarm *alarm, ktime_t now),
TP_ARGS(alarm, now)
);
DEFINE_EVENT(alarm_class, alarmtimer_cancel,
TP_PROTO(struct alarm *alarm, ktime_t now),
TP_ARGS(alarm, now)
);
#endif /* _TRACE_ALARMTIMER_H */
/* This part must be outside protection */
#include <trace/define_trace.h>

53
kernel/time/alarmtimer.c
View File

@ -26,6 +26,9 @@
#include <linux/workqueue.h>
#include <linux/freezer.h>
#define CREATE_TRACE_POINTS
#include <trace/events/alarmtimer.h>
/**
* struct alarm_base - Alarm timer bases
* @lock: Lock for syncrhonized access to the base
@ -40,7 +43,9 @@ static struct alarm_base {
clockid_t base_clockid;
} alarm_bases[ALARM_NUMTYPE];
/* freezer delta & lock used to handle clock_nanosleep triggered wakeups */
/* freezer information to handle clock_nanosleep triggered wakeups */
static enum alarmtimer_type freezer_alarmtype;
static ktime_t freezer_expires;
static ktime_t freezer_delta;
static DEFINE_SPINLOCK(freezer_delta_lock);
@ -194,6 +199,7 @@ static enum hrtimer_restart alarmtimer_fired(struct hrtimer *timer)
}
spin_unlock_irqrestore(&base->lock, flags);
trace_alarmtimer_fired(alarm, base->gettime());
return ret;
}
@ -218,15 +224,16 @@ EXPORT_SYMBOL_GPL(alarm_expires_remaining);
*/
static int alarmtimer_suspend(struct device *dev)
{
struct rtc_time tm;
ktime_t min, now;
unsigned long flags;
ktime_t min, now, expires;
int i, ret, type;
struct rtc_device *rtc;
int i;
int ret;
unsigned long flags;
struct rtc_time tm;
spin_lock_irqsave(&freezer_delta_lock, flags);
min = freezer_delta;
expires = freezer_expires;
type = freezer_alarmtype;
freezer_delta = ktime_set(0, 0);
spin_unlock_irqrestore(&freezer_delta_lock, flags);
@ -247,8 +254,11 @@ static int alarmtimer_suspend(struct device *dev)
if (!next)
continue;
delta = ktime_sub(next->expires, base->gettime());
if (!min.tv64 || (delta.tv64 < min.tv64))
if (!min.tv64 || (delta.tv64 < min.tv64)) {
expires = next->expires;
min = delta;
type = i;
}
}
if (min.tv64 == 0)
return 0;
@ -258,6 +268,8 @@ static int alarmtimer_suspend(struct device *dev)
return -EBUSY;
}
trace_alarmtimer_suspend(expires, type);
/* Setup an rtc timer to fire that far in the future */
rtc_timer_cancel(rtc, &rtctimer);
rtc_read_time(rtc, &tm);
@ -295,15 +307,32 @@ static int alarmtimer_resume(struct device *dev)
static void alarmtimer_freezerset(ktime_t absexp, enum alarmtimer_type type)
{
ktime_t delta;
struct alarm_base *base;
unsigned long flags;
struct alarm_base *base = &alarm_bases[type];
ktime_t delta;
switch(type) {
case ALARM_REALTIME:
base = &alarm_bases[ALARM_REALTIME];
type = ALARM_REALTIME_FREEZER;
break;
case ALARM_BOOTTIME:
base = &alarm_bases[ALARM_BOOTTIME];
type = ALARM_BOOTTIME_FREEZER;
break;
default:
WARN_ONCE(1, "Invalid alarm type: %d\n", type);
return;
}
delta = ktime_sub(absexp, base->gettime());
spin_lock_irqsave(&freezer_delta_lock, flags);
if (!freezer_delta.tv64 || (delta.tv64 < freezer_delta.tv64))
if (!freezer_delta.tv64 || (delta.tv64 < freezer_delta.tv64)) {
freezer_delta = delta;
freezer_expires = absexp;
freezer_alarmtype = type;
}
spin_unlock_irqrestore(&freezer_delta_lock, flags);
}
@ -342,6 +371,8 @@ void alarm_start(struct alarm *alarm, ktime_t start)
alarmtimer_enqueue(base, alarm);
hrtimer_start(&alarm->timer, alarm->node.expires, HRTIMER_MODE_ABS);
spin_unlock_irqrestore(&base->lock, flags);
trace_alarmtimer_start(alarm, base->gettime());
}
EXPORT_SYMBOL_GPL(alarm_start);
@ -390,6 +421,8 @@ int alarm_try_to_cancel(struct alarm *alarm)
if (ret >= 0)
alarmtimer_dequeue(base, alarm);
spin_unlock_irqrestore(&base->lock, flags);
trace_alarmtimer_cancel(alarm, base->gettime());
return ret;
}
EXPORT_SYMBOL_GPL(alarm_try_to_cancel);