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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 <[email protected]>
Signed-off-by: John Stultz <[email protected]>
Acked-by: Steven Rostedt <[email protected]>
Cc: Prarit Bhargava <[email protected]>
Cc: Richard Cochran <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Thomas Gleixner <[email protected]>
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Updated struct alarm and struct alarm_timer descriptions.
Cc: Prarit Bhargava <[email protected]>
Cc: Richard Cochran <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Ingo Molnar <[email protected]>
Signed-off-by: Pratyush Patel <[email protected]>
Signed-off-by: John Stultz <[email protected]>
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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 <[email protected]>
Acked-by: Peter Zijlstra <[email protected]>
Cc: Preeti U Murthy <[email protected]>
Cc: Viresh Kumar <[email protected]>
Cc: Marcelo Tosatti <[email protected]>
Cc: Frederic Weisbecker <[email protected]>
Cc: John Stultz <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Thomas Gleixner <[email protected]>
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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 <[email protected]>
Signed-off-by: John Stultz <[email protected]>
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No one is using these alarmtimer state helpers, so yank them.
Cc: Arve Hjønnevåg <[email protected]>
Cc: Colin Cross <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Signed-off-by: John Stultz <[email protected]>
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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 <[email protected]>
Cc: Colin Cross <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Reported-by: Arve Hjønnevåg <[email protected]>
Tested-by: Arve Hjønnevåg <[email protected]>
Signed-off-by: John Stultz <[email protected]>
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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 <[email protected]>
CC: Thomas Gleixner <[email protected]>
CC: Android Kernel Team <[email protected]>
Signed-off-by: John Stultz <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
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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 <[email protected]>
Signed-off-by: John Stultz <[email protected]>
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In order to allow for functionality like try_to_cancel, add
more refined state tracking (similar to hrtimers).
CC: Thomas Gleixner <[email protected]>
Signed-off-by: John Stultz <[email protected]>
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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 <[email protected]>
Signed-off-by: John Stultz <[email protected]>
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In order to avoid wasting time expiring and re-adding very high freq
periodic alarmtimers, introduce alarm_forward() which is similar to
hrtimer_forward and moves the timer to the next future expiration time
and returns the number of overruns.
CC: Thomas Gleixner <[email protected]>
Signed-off-by: John Stultz <[email protected]>
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In order to properly fix the denial of service issue with high freq
periodic alarm timers, we need to push the re-arming logic into the
alarm timer handler, much as the hrtimer code does.
This patch introduces alarmtimer_restart enum and changes the
alarmtimer handler declarations to use it as a return value. Further,
to ease following changes, it extends the alarmtimer handler functions
to also take the time at expiration. No logic is yet modified.
CC: Thomas Gleixner <[email protected]>
Signed-off-by: John Stultz <[email protected]>
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This patch addresses a number of minor comment improvements and
other minor issues from Thomas' review of the alarmtimers code.
CC: Thomas Gleixner <[email protected]>
Signed-off-by: John Stultz <[email protected]>
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This provides the in kernel interface and infrastructure for
alarm-timers.
Alarm-timers are a hybrid style timer, similar to hrtimers,
but when the system is suspended, the RTC device is set to
fire and wake the system for when the soonest alarm-timer
expires.
The concept for Alarm-timers was inspired by the Android Alarm
driver (by Arve Hjønnevåg) found in the Android kernel tree.
See: http://android.git.kernel.org/?p=kernel/common.git;a=blob;f=drivers/rtc/alarm.c;h=1250edfbdf3302f5e4ea6194847c6ef4bb7beb1c;hb=android-2.6.36
This in-kernel interface should be fairly compatible with the
Android alarm driver in-kernel interface, but has the advantage
of utilizing the new RTC timerqueue code instead of doing direct
RTC manipulation.
CC: Arve Hjønnevåg <[email protected]>
CC: Thomas Gleixner <[email protected]>
CC: Alessandro Zummo <[email protected]>
Acked-by: Arnd Bergmann <[email protected]>
Signed-off-by: John Stultz <[email protected]>
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