linux-toradex.git/kernel/time/timekeeping.c, branch v3.0.3

timerfd: Allow timers to be cancelled when clock was set

2011-05-02T19:39:15+00:00

Some applications must be aware of clock realtime being set
backward. A simple example is a clock applet which arms a timer for
the next minute display. If clock realtime is set backward then the
applet displays a stale time for the amount of time which the clock
was set backwards. Due to that applications poll the time because we
don't have an interface.

Extend the timerfd interface by adding a flag which puts the timer
onto a different internal realtime clock. All timers on this clock are
expired whenever the clock was set.

The timerfd core records the monotonic offset when the timer is
created. When the timer is armed, then the current offset is compared
to the previous recorded offset. When it has changed, then
timerfd_settime returns -ECANCELED. When a timer is read the offset is
compared and if it changed -ECANCELED returned to user space. Periodic
timers are not rearmed in the cancelation case.

Signed-off-by: Thomas Gleixner 
Acked-by: John Stultz 
Cc: Chris Friesen 
Tested-by: Kay Sievers 
Cc: "Kirill A. Shutemov" 
Cc: Peter Zijlstra 
Cc: Davide Libenzi 
Reviewed-by: Alexander Shishkin 
Link: http://lkml.kernel.org/r/%3Calpine.LFD.2.02.1104271359580.3323%40ionos%3E
Signed-off-by: Thomas Gleixner

hrtimers: Prepare for cancel on clock was set timers

2011-05-02T19:37:58+00:00

Make clock_was_set() unconditional and rename hres_timers_resume to
hrtimers_resume. This is a preparatory patch for hrtimers which are
cancelled when clock realtime was set.

Signed-off-by: Thomas Gleixner

time: Add timekeeping_inject_sleeptime

2011-04-26T21:01:41+00:00

Some platforms cannot implement read_persistent_clock, as
their RTC devices are only accessible when interrupts are enabled.
This keeps them from being used by the timekeeping code on resume
to measure the time in suspend.

The RTC layer tries to work around this, by calling do_settimeofday
on resume after irqs are reenabled to set the time properly. However,
this only corrects CLOCK_REALTIME, and does not properly adjust
the sleep time value. This causes btime in /proc/stat to be incorrect
as well as making the new CLOCK_BOTTTIME inaccurate.

This patch resolves the issue by introducing a new timekeeping hook
to allow the RTC layer to inject the sleep time on resume.

The code also checks to make sure that read_persistent_clock is
nonfunctional before setting the sleep time, so that should the RTC's
HCTOSYS option be configured in on a system that does support
read_persistent_clock we will not increase the total_sleep_time twice.

CC: Arve Hjønnevåg 
CC: Thomas Gleixner 
Acked-by: Arnd Bergmann 
Signed-off-by: John Stultz

timekeeping: Use syscore_ops instead of sysdev class and sysdev

2011-03-23T21:16:04+00:00

The timekeeping subsystem uses a sysdev class and a sysdev for
executing timekeeping_suspend() after interrupts have been turned off
on the boot CPU (during system suspend) and for executing
timekeeping_resume() before turning on interrupts on the boot CPU
(during system resume).  However, since both of these functions
ignore their arguments, the entire mechanism may be replaced with a
struct syscore_ops object which is simpler.

Signed-off-by: Rafael J. Wysocki 
Reviewed-by: Thomas Gleixner

time: Extend get_xtime_and_monotonic_offset() to also return sleep

2011-02-21T20:53:07+00:00

Extend get_xtime_and_monotonic_offset to
get_xtime_and_monotonic_and_sleep_offset().

CC: Jamie Lokier 
CC: Thomas Gleixner 
CC: Alexander Shishkin 
CC: Arve Hjønnevåg 
Signed-off-by: John Stultz

time: Introduce get_monotonic_boottime and ktime_get_boottime

2011-02-21T20:53:05+00:00

This adds new functions that return the monotonic time since boot
(in other words, CLOCK_MONOTONIC + suspend time).

CC: Jamie Lokier 
CC: Thomas Gleixner 
CC: Alexander Shishkin 
CC: Arve Hjønnevåg 
Signed-off-by: John Stultz

time: Introduce timekeeping_inject_offset

2011-02-02T14:28:18+00:00

This adds a kernel-internal timekeeping interface to add or subtract
a fixed amount from CLOCK_REALTIME. This makes it so kernel users or
interfaces trying to do so do not have to read the time, then add an
offset and then call settimeofday(), which adds some extra error in
comparision to just simply adding the offset in the kernel timekeeping
core.

Signed-off-by: John Stultz 
Signed-off-by: Richard Cochran 
LKML-Reference: <20110201134419.584311693@linutronix.de>
Signed-off-by: Thomas Gleixner

time: Correct the settime parameters

2011-02-02T14:28:11+00:00

Both settimeofday() and clock_settime() promise with a 'const'
attribute not to alter the arguments passed in. This patch adds the
missing 'const' attribute into the various kernel functions
implementing these calls.

Signed-off-by: Richard Cochran 
Acked-by: John Stultz 
LKML-Reference: <20110201134417.545698637@linutronix.de>
Signed-off-by: Thomas Gleixner

time: Provide xtime_update()

2011-01-31T13:55:43+00:00

xtime_update() takes xtime_lock write locked and calls
do_timer(). Provided to replace the do_timer() calls in the
architecture code.

Signed-off-by: Torben Hohn 
Cc: Peter Zijlstra 
Cc: johnstul@us.ibm.com
Cc: yong.zhang0@gmail.com
Cc: hch@infradead.org
LKML-Reference: <20110127145910.23248.21379.stgit@localhost>
Signed-off-by: Thomas Gleixner

time: Remove unused __get_wall_to_monotonic()