linux-toradex.git/include/linux/alarmtimer.h, branch v4.13-rc4

alarmtimer: Add tracepoints for alarm timers

2016-12-01T13:45:08+00:00

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 
Signed-off-by: John Stultz 
Acked-by: Steven Rostedt 
Cc: Prarit Bhargava 
Cc: Richard Cochran 
Link: http://lkml.kernel.org/r/1480372524-15181-5-git-send-email-john.stultz@linaro.org
Signed-off-by: Thomas Gleixner

alarmtimer: Fix comments describing structure fields

2016-06-20T19:47:09+00:00

Updated struct alarm and struct alarm_timer descriptions.

Cc: Prarit Bhargava 
Cc: Richard Cochran 
Cc: Thomas Gleixner 
Cc: Ingo Molnar 
Signed-off-by: Pratyush Patel 
Signed-off-by: John Stultz

alarmtimer: Get rid of unused return value

2015-04-22T15:06:52+00:00

We want to get rid of the hrtimer_start() return value and the alarm
timer return value is nowhere used. Remove it.

Signed-off-by: Thomas Gleixner 
Acked-by: Peter Zijlstra 
Cc: Preeti U Murthy 
Cc: Viresh Kumar 
Cc: Marcelo Tosatti 
Cc: Frederic Weisbecker 
Cc: John Stultz 
Link: http://lkml.kernel.org/r/20150414203503.243910615@linutronix.de
Signed-off-by: Thomas Gleixner

alarmtimer: Add functions for timerfd support

2013-05-29T19:57:34+00:00

Add functions needed for hooking up alarmtimer to timerfd:

* alarm_restart: Similar to hrtimer_restart, restart an alarmtimer after
  the expires time has already been updated (as with alarm_forward).

* alarm_forward_now: Similar to hrtimer_forward_now, move the expires
  time forward to an interval from the current time of the associated clock.

* alarm_start_relative: Start an alarmtimer with an expires time relative to
  the current time of the associated clock.

* alarm_expires_remaining: Similar to hrtimer_expires_remaining, return the
  amount of time remaining until alarm expiry.

Signed-off-by: Todd Poynor 
Signed-off-by: John Stultz

alarmtimer: Remove unused helpers & defines

2012-09-24T16:38:02+00:00

No one is using these alarmtimer state helpers, so yank them.

Cc: Arve Hjønnevåg 
Cc: Colin Cross 
Cc: Thomas Gleixner 
Signed-off-by: John Stultz

alarmtimer: Use hrtimer per-alarm instead of per-base

2012-09-24T16:38:02+00:00

Arve Hjønnevåg reported numerous crashes from the
"BUG_ON(timer->state != HRTIMER_STATE_CALLBACK)" check
in __run_hrtimer after it called alarmtimer_fired.

It ends up the alarmtimer code was not properly handling
possible failures of hrtimer_try_to_cancel, and because
these faulres occur when the underlying base hrtimer is
being run, this limits the ability to properly handle
modifications to any alarmtimers on that base.

Because much of the logic duplicates the hrtimer logic,
it seems that we might as well have a per-alarmtimer
hrtimer, and avoid the extra complextity of trying to
multiplex many alarmtimers off of one hrtimer.

Thus this patch moves the hrtimer to the alarm structure
and simplifies the management logic.

Changelog:
v2:
* Includes a fix for double alarm_start calls found by
  Arve

Cc: Arve Hjønnevåg 
Cc: Colin Cross 
Cc: Thomas Gleixner 
Reported-by: Arve Hjønnevåg 
Tested-by: Arve Hjønnevåg 
Signed-off-by: John Stultz

alarmtimer: Provide accessor to alarmtimer rtc device

2012-04-20T21:56:36+00:00

The Android alarm interface provides a settime call that sets both
the alarmtimer RTC device and CLOCK_REALTIME to the same value.

Since there may be multiple rtc devices, provide a hook to access the
one the alarmtimer infrastructure is using.

CC: Colin Cross 
CC: Thomas Gleixner 
CC: Android Kernel Team 
Signed-off-by: John Stultz 
Signed-off-by: Greg Kroah-Hartman

alarmtimers: Add try_to_cancel functionality

2011-08-10T21:55:29+00:00

There's a number of edge cases when cancelling a alarm, so
to be sure we accurately do so, introduce try_to_cancel, which
returns proper failure errors if it cannot. Also modify cancel
to spin until the alarm is properly disabled.

CC: Thomas Gleixner 
Signed-off-by: John Stultz

alarmtimers: Add more refined alarm state tracking

2011-08-10T21:55:27+00:00

In order to allow for functionality like try_to_cancel, add
more refined  state tracking (similar to hrtimers).

CC: Thomas Gleixner 
Signed-off-by: John Stultz

alarmtimers: Remove period from alarm structure

2011-08-10T21:55:26+00:00

Now that periodic alarmtimers are managed by the handler function,
remove the period value from the alarm structure and let the handlers
manage the interval on their own.

CC: Thomas Gleixner 
Signed-off-by: John Stultz