linux-toradex.git/kernel/time, branch v3.0-rc3

clockevents: Handle empty cpumask gracefully

2011-06-03T09:13:33+00:00

For UP it's stupid to request an initialized cpumask for the clock
event devices. Though we need the mask set even on UP to avoid a
horrible ifdeffery especially in the broadcast code.

For SMP we can at least try to survive with a warning and set the
cpumask of the cpu we're running on. That gives a decent chance to
bring the machine up and retrieve the debug info.

Signed-off-by: Thomas Gleixner 
Cc: Linus Walleij 
Cc: Russell King - ARM Linux 
Cc: Stephen Boyd

hrtimers: Avoid touching inactive timer bases

2011-05-23T11:59:54+00:00

Instead of iterating over all possible timer bases avoid it by marking
the active bases in the cpu base.

Signed-off-by: Thomas Gleixner 
Reviewed-by: Peter Zijlstra

Merge branch 'timers/urgent' into timers/core

2011-05-20T18:08:05+00:00

Reason: Get upstream fixes and kfree_rcu which is necessary for a
follow up patch.

Signed-off-by: Thomas Gleixner

clockevents/source: Use u64 to make 32bit happy

2011-05-20T08:50:52+00:00

unsigned long is not 64bit on 32bit machine.

Signed-off-by: Thomas Gleixner

Merge branch 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

2011-05-20T00:45:08+00:00

* 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  hrtimer: Make lookup table const
  RTC: Disable CONFIG_RTC_CLASS from being built as a module
  timers: Fix alarmtimer build issues when CONFIG_RTC_CLASS=n
  timers: Remove delayed irqwork from alarmtimers implementation
  timers: Improve alarmtimer comments and minor fixes
  timers: Posix interface for alarm-timers
  timers: Introduce in-kernel alarm-timer interface
  timers: Add rb_init_node() to allow for stack allocated rb nodes
  time: Add timekeeping_inject_sleeptime

Merge branch 'timers-clockevents-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

2011-05-20T00:44:40+00:00

* 'timers-clockevents-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86: hpet: Cleanup the clockevents init and register code
  x86: Convert PIT to clockevents_config_and_register()
  clockevents: Provide interface to reconfigure an active clock event device
  clockevents: Provide combined configure and register function
  clockevents: Restructure clock_event_device members
  clocksource: Get rid of the hardcoded 5 seconds sleep time limit
  clocksource: Restructure clocksource struct members

clockevents: Provide interface to reconfigure an active clock event device

2011-05-19T12:24:16+00:00

Some ARM SoCs have clock event devices which have their frequency
modified due to frequency scaling. Provide an interface which allows
to reconfigure an active device. After reconfiguration reprogram the
current pending event.

Signed-off-by: Thomas Gleixner 
Cc: LAK 
Cc: John Stultz 
Acked-by: Linus Walleij 
Reviewed-by: Ingo Molnar 
Link: http://lkml.kernel.org/r/%3C20110518210136.437459958%40linutronix.de%3E

clockevents: Provide combined configure and register function

2011-05-19T12:24:15+00:00

All clockevent devices have the same open coded initialization
functions. Provide an interface which does all necessary
initialization in the core code.

Signed-off-by: Thomas Gleixner 
Cc: John Stultz 
Reviewed-by: Ingo Molnar 
Link: http://lkml.kernel.org/r/%3C20110518210136.331975870%40linutronix.de%3E

clocksource: Get rid of the hardcoded 5 seconds sleep time limit

2011-05-19T12:24:15+00:00

Slow clocksources can have a way longer sleep time than 5 seconds and
even fast ones can easily cope with 600 seconds and still maintain
proper accuracy.

Signed-off-by: Thomas Gleixner 
Cc: John Stultz 
Reviewed-by: Ingo Molnar 
Link: http://lkml.kernel.org/r/%3C20110518210136.109811585%40linutronix.de%3E

tick: Clear broadcast active bit when switching to oneshot

2011-05-16T21:35:41+00:00

The first cpu which switches from periodic to oneshot mode switches
also the broadcast device into oneshot mode. The broadcast device
serves as a backup for per cpu timers which stop in deeper
C-states. To avoid starvation of the cpus which might be in idle and
depend on broadcast mode it marks the other cpus as broadcast active
and sets the brodcast expiry value of those cpus to the next tick.

The oneshot mode broadcast bit for the other cpus is sticky and gets
only cleared when those cpus exit idle. If a cpu was not idle while
the bit got set in consequence the bit prevents that the broadcast
device is armed on behalf of that cpu when it enters idle for the
first time after it switched to oneshot mode.

In most cases that goes unnoticed as one of the other cpus has usually
a timer pending which keeps the broadcast device armed with a short
timeout. Now if the only cpu which has a short timer active has the
bit set then the broadcast device will not be armed on behalf of that
cpu and will fire way after the expected timer expiry. In the case of
Christians bug report it took ~145 seconds which is about half of the
wrap around time of HPET (the limit for that device) due to the fact
that all other cpus had no timers armed which expired before the 145
seconds timeframe.

The solution is simply to clear the broadcast active bit
unconditionally when a cpu switches to oneshot mode after the first
cpu switched the broadcast device over. It's not idle at that point
otherwise it would not be executing that code.

[ I fundamentally hate that broadcast crap. Why the heck thought some
  folks that when going into deep idle it's a brilliant concept to
  switch off the last device which brings the cpu back from that
  state? ]

Thanks to Christian for providing all the valuable debug information!

Reported-and-tested-by: Christian Hoffmann 
Cc: John Stultz 
Link: http://lkml.kernel.org/r/%3Calpine.LFD.2.02.1105161105170.3078%40ionos%3E
Cc: stable@kernel.org
Signed-off-by: Thomas Gleixner