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A queued hrtimer that gets restarted (hrtimer_start*() while
hrtimer_is_queued()) will briefly appear as unqueued/inactive, even
though the timer has always been active, we just moved it.
Close this hole by preserving timer->state in
hrtimer_start_range_ns()'s remove_hrtimer() call.
Reported-by: Oleg Nesterov <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Thomas Gleixner <[email protected]>
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I do not understand HRTIMER_STATE_MIGRATE. Unless I am totally
confused it looks buggy and simply unneeded.
migrate_hrtimer_list() sets it to keep hrtimer_active() == T, but this
is not enough: this can fool, say, hrtimer_is_queued() in
dequeue_signal().
Can't migrate_hrtimer_list() simply use HRTIMER_STATE_ENQUEUED?
This fixes the race and we can kill STATE_MIGRATE.
Signed-off-by: Oleg Nesterov <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Thomas Gleixner <[email protected]>
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In 0c4a5fc95b1df (Add leap-second timer edge testing to
leap-a-day.c), we added a timer to the test which checks to make
sure timers near the leapsecond edge behave correctly.
However, the output generated from the timer uses ctime_r, which
isn't async-signal safe, and should that signal land while the
main test is using ctime_r to print its output, its possible for
the test to deadlock on glibc internal locks.
Thus this patch reworks the output to avoid using ctime_r in
the signal handler.
Signed-off-by: John Stultz <[email protected]>
Cc: Prarit Bhargava <[email protected]>
Cc: Daniel Bristot de Oliveira <[email protected]>
Cc: Richard Cochran <[email protected]>
Cc: Jan Kara <[email protected]>
Cc: Jiri Bohac <[email protected]>
Cc: Shuah Khan <[email protected]>
Cc: Ingo Molnar <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Thomas Gleixner <[email protected]>
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The fix in d151832650ed9 (time: Move clock_was_set_seq update
before updating shadow-timekeeper) was unfortunately incomplete.
The main gist of that change was to do the shadow-copy update
last, so that any state changes were properly duplicated, and
we wouldn't accidentally have stale data in the shadow.
Unfortunately in the main update_wall_time() logic, we update
use the shadow-timekeeper to calculate the next update values,
then while holding the lock, copy the shadow-timekeeper over,
then call timekeeping_update() to do some additional
bookkeeping, (skipping the shadow mirror). The bug with this is
the additional bookkeeping isn't all read-only, and some
changes timkeeper state. Thus we might then overwrite this state
change on the next update.
To avoid this problem, do the timekeeping_update() on the
shadow-timekeeper prior to copying the full state over to
the real-timekeeper.
This avoids problems with both the clock_was_set_seq and
next_leap_ktime being overwritten and possibly the
fast-timekeepers as well.
Many thanks to Prarit for his rigorous testing, which discovered
this problem, along with Prarit and Daniel's work validating this
fix.
Reported-by: Prarit Bhargava <[email protected]>
Tested-by: Prarit Bhargava <[email protected]>
Tested-by: Daniel Bristot de Oliveira <[email protected]>
Signed-off-by: John Stultz <[email protected]>
Cc: Richard Cochran <[email protected]>
Cc: Jan Kara <[email protected]>
Cc: Jiri Bohac <[email protected]>
Cc: Ingo Molnar <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Thomas Gleixner <[email protected]>
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CLOCK_EVT_MODE_* macros are present for backward compatibility (as most
of the drivers are still using old ->set_mode() interface).
These macro's shouldn't be used anymore in code, that is common to both
driver interfaces, i.e. ->set_mode() and ->set_state_*().
Drivers implementing ->set_state_*() interface, which have their
clkevt->mode set to 0 (clkevt device structures are normally globally
defined), will not participate in suspend/resume as they will always be
marked as UNUSED.
Fix this by checking state of the clockevent device instead of mode,
which is updated for both the interfaces.
Fixes: ac34ad27fc16 ("clockevents: Do not suspend/resume if unused")
Signed-off-by: Viresh Kumar <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Link: http://lkml.kernel.org/r/a1964eef6e8a47d02b1ff9083c6c91f73f0ff643.1434537215.git.viresh.kumar@linaro.org
Signed-off-by: Thomas Gleixner <[email protected]>
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Prarit reported an issue w/ timers around the leapsecond, where a
timer set for Midnight UTC (00:00:00) might fire a second early right
before the leapsecond (23:59:60 - though it appears as a repeated
23:59:59) is applied.
So I've updated the leap-a-day.c test to integrate a similar test,
where we set a timer and check if it triggers at the right time, and
if the ntp state transition is managed properly.
Reported-by: Daniel Bristot de Oliveira <[email protected]>
Reported-by: Prarit Bhargava <[email protected]>
Signed-off-by: John Stultz <[email protected]>
Cc: Richard Cochran <[email protected]>
Cc: Jan Kara <[email protected]>
Cc: Jiri Bohac <[email protected]>
Cc: Shuah Khan <[email protected]>
Cc: Ingo Molnar <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Thomas Gleixner <[email protected]>
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Since the leapsecond is applied at tick-time, this means there is a
small window of time at the start of a leap-second where we cross into
the next second before applying the leap.
This patch modified adjtimex so that the leap-second is applied on the
second edge. Providing more correct leapsecond behavior.
This does make it so that adjtimex()'s returned time values can be
inconsistent with time values read from gettimeofday() or
clock_gettime(CLOCK_REALTIME,...) for a brief period of one tick at
the leapsecond. However, those other interfaces do not provide the
TIME_OOP time_state return that adjtimex() provides, which allows the
leapsecond to be properly represented. They instead only see a time
discontinuity, and cannot tell the first 23:59:59 from the repeated
23:59:59 leap second.
This seems like a reasonable tradeoff given clock_gettime() /
gettimeofday() cannot properly represent a leapsecond, and users
likely care more about performance, while folks who are using
adjtimex() more likely care about leap-second correctness.
Signed-off-by: John Stultz <[email protected]>
Cc: Prarit Bhargava <[email protected]>
Cc: Daniel Bristot de Oliveira <[email protected]>
Cc: Richard Cochran <[email protected]>
Cc: Jan Kara <[email protected]>
Cc: Jiri Bohac <[email protected]>
Cc: Ingo Molnar <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Thomas Gleixner <[email protected]>
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Currently, leapsecond adjustments are done at tick time. As a result,
the leapsecond was applied at the first timer tick *after* the
leapsecond (~1-10ms late depending on HZ), rather then exactly on the
second edge.
This was in part historical from back when we were always tick based,
but correcting this since has been avoided since it adds extra
conditional checks in the gettime fastpath, which has performance
overhead.
However, it was recently pointed out that ABS_TIME CLOCK_REALTIME
timers set for right after the leapsecond could fire a second early,
since some timers may be expired before we trigger the timekeeping
timer, which then applies the leapsecond.
This isn't quite as bad as it sounds, since behaviorally it is similar
to what is possible w/ ntpd made leapsecond adjustments done w/o using
the kernel discipline. Where due to latencies, timers may fire just
prior to the settimeofday call. (Also, one should note that all
applications using CLOCK_REALTIME timers should always be careful,
since they are prone to quirks from settimeofday() disturbances.)
However, the purpose of having the kernel do the leap adjustment is to
avoid such latencies, so I think this is worth fixing.
So in order to properly keep those timers from firing a second early,
this patch modifies the ntp and timekeeping logic so that we keep
enough state so that the update_base_offsets_now accessor, which
provides the hrtimer core the current time, can check and apply the
leapsecond adjustment on the second edge. This prevents the hrtimer
core from expiring timers too early.
This patch does not modify any other time read path, so no additional
overhead is incurred. However, this also means that the leap-second
continues to be applied at tick time for all other read-paths.
Apologies to Richard Cochran, who pushed for similar changes years
ago, which I resisted due to the concerns about the performance
overhead.
While I suspect this isn't extremely critical, folks who care about
strict leap-second correctness will likely want to watch
this. Potentially a -stable candidate eventually.
Originally-suggested-by: Richard Cochran <[email protected]>
Reported-by: Daniel Bristot de Oliveira <[email protected]>
Reported-by: Prarit Bhargava <[email protected]>
Signed-off-by: John Stultz <[email protected]>
Cc: Richard Cochran <[email protected]>
Cc: Jan Kara <[email protected]>
Cc: Jiri Bohac <[email protected]>
Cc: Shuah Khan <[email protected]>
Cc: Ingo Molnar <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Thomas Gleixner <[email protected]>
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Currently the leapsecond logic uses what looks like magic values.
Improve this by defining SECS_PER_DAY and using that macro
to make the logic more clear.
Signed-off-by: John Stultz <[email protected]>
Cc: Prarit Bhargava <[email protected]>
Cc: Daniel Bristot de Oliveira <[email protected]>
Cc: Richard Cochran <[email protected]>
Cc: Jan Kara <[email protected]>
Cc: Jiri Bohac <[email protected]>
Cc: Ingo Molnar <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Thomas Gleixner <[email protected]>
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It was reported that 868a3e915f7f5eba (hrtimer: Make offset
update smarter) was causing timer problems after suspend/resume.
The problem with that change is the modification to
clock_was_set_seq in timekeeping_update is done prior to
mirroring the time state to the shadow-timekeeper. Thus the
next time we do update_wall_time() the updated sequence is
overwritten by whats in the shadow copy.
This patch moves the shadow-timekeeper mirroring to the end
of the function, after all updates have been made, so all data
is kept in sync.
(This patch also affects the update_fast_timekeeper calls which
were also problematically done prior to the mirroring).
Reported-and-tested-by: Jeremiah Mahler <[email protected]>
Signed-off-by: John Stultz <[email protected]>
Cc: Preeti U Murthy <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Viresh Kumar <[email protected]>
Cc: Marcelo Tosatti <[email protected]>
Cc: Frederic Weisbecker <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Thomas Gleixner <[email protected]>
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clocksource messages aren't prefixed in dmesg so it's a bit unclear
what subsystem emits the messages.
Use pr_fmt and pr_<level> to auto-prefix the messages appropriately.
Miscellanea:
o Remove "Warning" from KERN_WARNING level messages
o Align "timekeeping watchdog: " messages
o Coalesce formats
o Align multiline arguments
Signed-off-by: Joe Perches <[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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To allow constant folding in usecs_to_jiffies() conditionally calls
the HZ dependent _usecs_to_jiffies() helpers or, when gcc can not
figure out constant folding, __usecs_to_jiffies, which is the renamed
original usecs_to_jiffies() function.
Signed-off-by: Nicholas Mc Guire <[email protected]>
Cc: Masahiro Yamada <[email protected]>
Cc: Sam Ravnborg <[email protected]>
Cc: Joe Perches <[email protected]>
Cc: John Stultz <[email protected]>
Cc: Andrew Hunter <[email protected]>
Cc: Paul Turner <[email protected]>
Cc: Michal Marek <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Thomas Gleixner <[email protected]>
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Refactor the usecs_to_jiffies conditional code part in time.c and
jiffies.h putting it into conditional functions rather than #ifdefs
to improve readability. This is analogous to the msecs_to_jiffies()
cleanup in commit ca42aaf0c861 ("time: Refactor msecs_to_jiffies")
Signed-off-by: Nicholas Mc Guire <[email protected]>
Cc: Masahiro Yamada <[email protected]>
Cc: Sam Ravnborg <[email protected]>
Cc: Joe Perches <[email protected]>
Cc: John Stultz <[email protected]>
Cc: Andrew Hunter <[email protected]>
Cc: Paul Turner <[email protected]>
Cc: Michal Marek <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Thomas Gleixner <[email protected]>
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... in the !CONFIG_HIGH_RES_TIMERS case too. And thus fix warnings like
this one:
net/sched/sch_api.c: In function ‘psched_show’:
net/sched/sch_api.c:1891:6: warning: format ‘%x’ expects argument of type ‘unsigned int’, but argument 6 has type ‘long int’ [-Wformat=]
(u32)NSEC_PER_SEC / hrtimer_resolution);
Signed-off-by: Borislav Petkov <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Thomas Gleixner <[email protected]>
Cc: Thomas Gleixner <[email protected]>
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http://git.linaro.org/people/daniel.lezcano/linux into timers/core
Pull clockevents/clocksource changes from Daniel Lezcano:
- Removed dead code in the files related to mach-msm for qcom (Stephen Boyd)
- Cleaned up code for exynos_mct (Krzysztof Kozlowski)
- Added the new timer lpc3220 (Joachim Eastwood)
- Added the new timer STM32 and ARM system timer (Maxime Coquelin)
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The only sensible way to make abuse of core internal fields obvious
and easy to grep for.
Signed-off-by: Thomas Gleixner <[email protected]>
Cc: Viresh Kumar <[email protected]>
Cc: Peter Zijlstra <[email protected]>
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Signed-off-by: Thomas Gleixner <[email protected]>
Cc: Viresh Kumar <[email protected]>
Cc: Peter Zijlstra <[email protected]>
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We want to rename dev->state, so provide proper get and set
functions. Rename clockevents_set_state() to
clockevents_switch_state() to avoid confusion.
Signed-off-by: Thomas Gleixner <[email protected]>
Cc: Viresh Kumar <[email protected]>
Cc: Peter Zijlstra <[email protected]>
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Use accessor functions to check the state of clockevent devices in
core code.
Signed-off-by: Viresh Kumar <[email protected]>
Cc: [email protected]
Cc: Peter Zijlstra <[email protected]>
Link: http://lkml.kernel.org/r/fa2b9869fd17f210eaa156ec2b594efd0230b6c7.1432192527.git.viresh.kumar@linaro.org
Signed-off-by: Thomas Gleixner <[email protected]>
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Some clockevent drivers, once migrated to use per-state callbacks,
need to check the state of the clockevent device in their callbacks or
interrupt handler.
Add accessor functions clockevent_state_*() to get this information.
Signed-off-by: Viresh Kumar <[email protected]>
Cc: [email protected]
Cc: Peter Zijlstra <[email protected]>
Link: http://lkml.kernel.org/r/04a717d490335c688dd7af899fbcede97e1bb8ee.1432192527.git.viresh.kumar@linaro.org
Signed-off-by: Thomas Gleixner <[email protected]>
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This patch fixes below warning spotted by kbuild test robot when building
with ARCH=powerpc:
drivers/clocksource/timer-stm32.c: In function 'stm32_clockevent_init':
>> drivers/clocksource/timer-stm32.c:140:9: warning: large integer implicitly
truncated to unsigned type [-Woverflow]
writel_relaxed(~0UL, data->base + TIM_ARR);
The fix consists in using 0U instead of 0UL.
Reported-by: kbuild test robot <[email protected]>
Signed-off-by: Maxime Coquelin <[email protected]>
Signed-off-by: Daniel Lezcano <[email protected]>
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STM32 MCUs feature 16 and 32 bits general purpose timers with prescalers.
The drivers detects whether the time is 16 or 32 bits, and applies a
1024 prescaler value if it is 16 bits.
Reviewed-by: Linus Walleij <[email protected]>
Tested-by: Chanwoo Choi <[email protected]>
Signed-off-by: Maxime Coquelin <[email protected]>
Signed-off-by: Daniel Lezcano <[email protected]>
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This adds documentation of device tree bindings for the
STM32 timer.
Tested-by: Chanwoo Choi <[email protected]>
Acked-by: Rob Herring <[email protected]>
Signed-off-by: Maxime Coquelin <[email protected]>
Signed-off-by: Daniel Lezcano <[email protected]>
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This patch adds clocksource support for ARMv7-M's System timer,
also known as SysTick.
Tested-by: Chanwoo Choi <[email protected]>
Acked-by: Daniel Lezcano <[email protected]>
Signed-off-by: Maxime Coquelin <[email protected]>
Signed-off-by: Daniel Lezcano <[email protected]>
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This adds documentation of device tree bindings for the
ARM System timer.
Tested-by: Chanwoo Choi <[email protected]>
Acked-by: Rob Herring <[email protected]>
Signed-off-by: Maxime Coquelin <[email protected]>
Signed-off-by: Daniel Lezcano <[email protected]>
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Add DT bindings documentation for lpc3220-timer. This timer is
used as clocksource on many NXP platforms.
Signed-off-by: Joachim Eastwood <[email protected]>
Signed-off-by: Daniel Lezcano <[email protected]>
Acked-by: Arnd Bergmann <[email protected]>
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Add support for using the NXP LPC timer as clocksource and clock
event. These timers are present on many NXP devices including
LPC32xx, LPC17xx, LPC18xx and LPC43xx.
The timer has a 32-bit timer counter register with a programmable
32-bit prescaler. It supports up to 4 compare match values with
interrupt generation and reset/stop timer counter action.
Signed-off-by: Joachim Eastwood <[email protected]>
Signed-off-by: Daniel Lezcano <[email protected]>
Reviewed-by: Ezequiel Garcia <[email protected]>
Acked-by: Arnd Bergmann <[email protected]>
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Since commit 228e3023eb04 ("Merge tag 'mct-exynos-for-v3.10' of ...") the
mct_init() was superseded by mct_init_dt() and is not referenced
anywhere. Remove it.
Signed-off-by: Krzysztof Kozlowski <[email protected]>
Signed-off-by: Daniel Lezcano <[email protected]>
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The struct clocksource 'mct_frc' is not exported and used outside so
make it static.
Signed-off-by: Krzysztof Kozlowski <[email protected]>
Signed-off-by: Daniel Lezcano <[email protected]>
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void
Return value of exynos4_mct_tick_clear() was never checked so it can
be safely changed to void.
Signed-off-by: Krzysztof Kozlowski <[email protected]>
Signed-off-by: Daniel Lezcano <[email protected]>
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This code is no longer used now that mach-msm has been removed.
Delete it.
Cc: David Brown <[email protected]>
Cc: Bryan Huntsman <[email protected]>
Cc: Daniel Walker <[email protected]>
Signed-off-by: Stephen Boyd <[email protected]>
Signed-off-by: Daniel Lezcano <[email protected]>
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There is no point in calling suspend/resume for unused clockevents as
they are already stopped and disabled.
This is really important for AT91 as the hardware is a trainwreck and
takes ages to synchronize.
Reported-by: Sylvain Rochet <[email protected]>
Signed-off-by: Alexandre Belloni <[email protected]>
Cc: Daniel Lezcano <[email protected]>
Cc: Nicolas Ferre <[email protected]>
Cc: Boris Brezillon <[email protected]>
Cc: Maxime Ripard <[email protected]>
Cc: [email protected]
Link: http://lkml.kernel.org/r/1421399151-26800-1-git-send-email-alexandre.belloni@free-electrons.com
Signed-off-by: Thomas Gleixner <[email protected]>
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Now that we have a read_boot_clock64() function available on every
architecture, and converted all the users to it, it's time to remove
the (now unused) read_boot_clock() completely from the kernel.
Cc: Thomas Gleixner <[email protected]>
Cc: Ingo Molnar <[email protected]>
Signed-off-by: Xunlei Pang <[email protected]>
[jstultz: Minor commit message tweak suggested by Ingo]
Signed-off-by: John Stultz <[email protected]>
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As part of addressing the "y2038 problem" for in-kernel uses,
this patch converts read_boot_clock() to read_boot_clock64()
and read_persistent_clock() to read_persistent_clock64() using
timespec64.
Rename some instances of 'timespec' to 'timespec64' in time.c and
related references
Cc: Thomas Gleixner <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Martin Schwidefsky <[email protected]>
Cc: Heiko Carstens <[email protected]>
Cc: [email protected]
Signed-off-by: Xunlei Pang <[email protected]>
[jstultz: Fixed minor style and grammer tweaks
pointed out by Ingo]
Signed-off-by: John Stultz <[email protected]>
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On 32-bit systems, timespec64_add_ns() calls __iter_div_u64_rem()
which needs math64.h, and we want to include time64.h in some
cases.
Cc: Thomas Gleixner <[email protected]>
Cc: Ingo Molnar <[email protected]>
Signed-off-by: Xunlei Pang <[email protected]>
Signed-off-by: John Stultz <[email protected]>
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The timer_start event now shows whether the timer is
deferrable in case of a low-res timer. The debug_activate
function now includes a deferrable flag while calling
the trace_timer_start event.
Cc: Thomas Gleixner <[email protected]>
Cc: Ingo Molnar <[email protected]>
Acked-by: Steven Rostedt <[email protected]>
Signed-off-by: Badhri Jagan Sridharan <[email protected]>
[jstultz: Fixed minor whitespace and grammer tweaks
pointed out by Ingo]
Signed-off-by: John Stultz <[email protected]>
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Ingo suggested that the timekeeping debugging variables
recently added should not be global, and should be tied
to the timekeeper's read_base.
Thus this patch implements that suggestion.
This version is different from the earlier versions
as it keeps the variables in the timekeeper structure
rather then in the tkr.
Cc: Ingo Molnar <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Prarit Bhargava <[email protected]>
Cc: Richard Cochran <[email protected]>
Signed-off-by: John Stultz <[email protected]>
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This patch series introduces a new function
u32 ktime_get_resolution_ns(void)
which allows to clean up some driver code.
In particular the IIO subsystem has a function to provide timestamps for
events but no means to get their resolution. So currently the dht11 driver
tries to guess the resolution in a rather messy and convoluted way. We
can do much better with the new code.
This API is not designed to be exposed to user space.
This has been tested on i386, sunxi and mxs.
Cc: Thomas Gleixner <[email protected]>
Cc: Ingo Molnar <[email protected]>
Signed-off-by: Harald Geyer <[email protected]>
[jstultz: Tweaked to make it build after upstream changes]
Signed-off-by: John Stultz <[email protected]>
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Invalid values may overflow later, leading to undefined behaviour when
multiplied by 60 to get the amount of seconds.
Cc: Thomas Gleixner <[email protected]>
Cc: Ingo Molnar <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
Signed-off-by: John Stultz <[email protected]>
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Somehow I missed to clean that up when applying the patches. Fix it up
now.
Reported-by: Joe Perches <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Cc: Nicholas Mc Guire <[email protected]>
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To avoid getting spurious interrupts on a tickless CPU, clockevent
device can now be stopped by switching to ONESHOT_STOPPED state.
The natural place for handling this transition is tick_program_event().
On 'expires == KTIME_MAX', we skip programming the event and so we need
to fix such call sites as well, to always call tick_program_event()
irrespective of the expires value.
Once the clockevent device is required again, check if it was earlier
put into ONESHOT_STOPPED state. If yes, switch its state to ONESHOT
before programming its event.
To make sure we haven't missed any corner case, add a WARN() for the
case where we try to reprogram clockevent device while we aren't
configured in ONESHOT_STOPPED state.
Signed-off-by: Viresh Kumar <[email protected]>
Cc: [email protected]
Cc: Frederic Weisbecker <[email protected]>
Cc: Kevin Hilman <[email protected]>
Cc: Daniel Lezcano <[email protected]>
Cc: Preeti U Murthy <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Link: http://lkml.kernel.org/r/5146b07be7f0bc497e0ebae036590ec2fa73e540.1428031396.git.viresh.kumar@linaro.org
Signed-off-by: Thomas Gleixner <[email protected]>
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When no timers/hrtimers are pending, the expiry time is set to a
special value: 'KTIME_MAX'. This normally happens with
NO_HZ_{IDLE|FULL} in both LOWRES/HIGHRES modes.
When 'expiry == KTIME_MAX', we either cancel the 'tick-sched' hrtimer
(NOHZ_MODE_HIGHRES) or skip reprogramming clockevent device
(NOHZ_MODE_LOWRES). But, the clockevent device is already
reprogrammed from the tick-handler for next tick.
As the clock event device is programmed in ONESHOT mode it will at
least fire one more time (unnecessarily). Timers on few
implementations (like arm_arch_timer, etc.) only support PERIODIC mode
and their drivers emulate ONESHOT over that. Which means that on these
platforms we will get spurious interrupts periodically (at last
programmed interval rate, normally tick rate).
In order to avoid spurious interrupts, the clockevent device should be
stopped or its interrupts should be masked.
A simple (yet hacky) solution to get this fixed could be: update
hrtimer_force_reprogram() to always reprogram clockevent device and
update clockevent drivers to STOP generating events (or delay it to
max time) when 'expires' is set to KTIME_MAX. But the drawback here is
that every clockevent driver has to be hacked for this particular case
and its very easy for new ones to miss this.
However, Thomas suggested to add an optional state ONESHOT_STOPPED to
solve this problem: lkml.org/lkml/2014/5/9/508.
This patch adds support for ONESHOT_STOPPED state in clockevents
core. It will only be available to drivers that implement the
state-specific callbacks instead of the legacy ->set_mode() callback.
Signed-off-by: Viresh Kumar <[email protected]>
Reviewed-by: Preeti U. Murthy <[email protected]>
Cc: [email protected]
Cc: Frederic Weisbecker <[email protected]>
Cc: Kevin Hilman <[email protected]>
Cc: Daniel Lezcano <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Link: http://lkml.kernel.org/r/b8b383a03ac07b13312c16850b5106b82e4245b5.1428031396.git.viresh.kumar@linaro.org
Signed-off-by: Thomas Gleixner <[email protected]>
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Make sure the upstream fixes are applied before adding further
modifications.
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To allow constant folding in msecs_to_jiffies() conditionally calls
the HZ dependent _msecs_to_jiffies() helpers or, when gcc can not
figure out constant folding, __msecs_to_jiffies which is the renamed
original msecs_to_jiffies() function.
Signed-off-by: Nicholas Mc Guire <[email protected]>
Cc: Masahiro Yamada <[email protected]>
Cc: Sam Ravnborg <[email protected]>
Cc: Joe Perches <[email protected]>
Cc: John Stultz <[email protected]>
Cc: Andrew Hunter <[email protected]>
Cc: Paul Turner <[email protected]>
Cc: Michal Marek <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Thomas Gleixner <[email protected]>
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Refactor the msecs_to_jiffies conditional code part in time.c and
jiffies.h putting it into conditional functions rather than #ifdefs
to improve readability.
[ tglx: Verified that there is no binary code change ]
Signed-off-by: Nicholas Mc Guire <[email protected]>
Cc: Masahiro Yamada <[email protected]>
Cc: Sam Ravnborg <[email protected]>
Cc: Joe Perches <[email protected]>
Cc: John Stultz <[email protected]>
Cc: Andrew Hunter <[email protected]>
Cc: Paul Turner <[email protected]>
Cc: Michal Marek <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Thomas Gleixner <[email protected]>
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kernel/time/timeconst.h is moved to include/generated/ and generated
by the top level Kbuild. This allows using timeconst.h in an earlier
build stage.
Signed-off-by: Nicholas Mc Guire <[email protected]>
Cc: Masahiro Yamada <[email protected]>
Cc: Sam Ravnborg <[email protected]>
Cc: Joe Perches <[email protected]>
Cc: John Stultz <[email protected]>
Cc: Andrew Hunter <[email protected]>
Cc: Paul Turner <[email protected]>
Cc: Michal Marek <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Thomas Gleixner <[email protected]>
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Two watchdog changes that came through different trees had a non
conflicting conflict, that is, one changed the semantics of a variable
but no actual code conflict happened. So the merge appeared fine, but
the resulting code did not behave as expected.
Commit 195daf665a62 ("watchdog: enable the new user interface of the
watchdog mechanism") changes the semantics of watchdog_user_enabled,
which thereafter is only used by the functions introduced by
b3738d293233 ("watchdog: Add watchdog enable/disable all functions").
There further appears to be a distinct lack of serialization between
setting and using watchdog_enabled, so perhaps we should wrap the
{en,dis}able_all() things in watchdog_proc_mutex.
This patch fixes a s2r failure reported by Michal; which I cannot
readily explain. But this does make the code internally consistent
again.
Reported-and-tested-by: Michal Hocko <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Pull MTD fixes from Brian Norris:
"Two MTD fixes for 4.1:
- readtest: the signal-handling code was clobbering the error codes
we should be handling/reporting in this test, rendering it useless.
Noticed by Coverity.
- the common SPI NOR flash DT binding (merged for 4.1-rc1) is being
revised, so let's change that before 4.1 is minted"
* tag 'for-linus-20150516' of git://git.infradead.org/linux-mtd:
Documentation: dt: mtd: replace "nor-jedec" binding with "jedec, spi-nor"
mtd: readtest: don't clobber error reports
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In the below two commits (see Fixes) we have periodic timers that can
stop themselves when they're no longer required, but need to be
(re)-started when their idle condition changes.
Further complications is that we want the timer handler to always do
the forward such that it will always correctly deal with the overruns,
and we do not want to race such that the handler has already decided
to stop, but the (external) restart sees the timer still active and we
end up with a 'lost' timer.
The problem with the current code is that the re-start can come before
the callback does the forward, at which point the forward from the
callback will WARN about forwarding an enqueued timer.
Now, conceptually its easy to detect if you're before or after the fwd
by comparing the expiration time against the current time. Of course,
that's expensive (and racy) because we don't have the current time.
Alternatively one could cache this state inside the timer, but then
everybody pays the overhead of maintaining this extra state, and that
is undesired.
The only other option that I could see is the external timer_active
variable, which I tried to kill before. I would love a nicer interface
for this seemingly simple 'problem' but alas.
Fixes: 272325c4821f ("perf: Fix mux_interval hrtimer wreckage")
Fixes: 77a4d1a1b9a1 ("sched: Cleanup bandwidth timers")
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: Sasha Levin <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
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