We do the exact same logic moving nsecs to secs in the
timekeeper in multiple places, so condense this into a
single function.
Signed-off-by: John Stultz <john.stultz@linaro.org>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Link: http://lkml.kernel.org/r/1342156917-25092-6-git-send-email-john.stultz@linaro.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
The timekeeper struct has a xtime_nsec, which keeps the
sub-nanosecond remainder. This ends up being somewhat
duplicative of the timekeeper.xtime.tv_nsec value, and we
have to do extra work to keep them apart, copying the full
nsec portion out and back in over and over.
This patch simplifies some of the logic by taking the timekeeper
xtime value and splitting it into timekeeper.xtime_sec and
reuses the timekeeper.xtime_nsec for the sub-second portion
(stored in higher res shifted nanoseconds).
This simplifies some of the accumulation logic. And will
allow for more accurate timekeeping once the vsyscall code
is updated to use the shifted nanosecond remainder.
Signed-off-by: John Stultz <john.stultz@linaro.org>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Link: http://lkml.kernel.org/r/1342156917-25092-5-git-send-email-john.stultz@linaro.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Ingo noted that using a u32 instead of int for shift values
would be better to make sure the compiler doesn't unnecessarily
use complex signed arithmetic.
Signed-off-by: John Stultz <john.stultz@linaro.org>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Link: http://lkml.kernel.org/r/1342156917-25092-4-git-send-email-john.stultz@linaro.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Ingo noted a number of places where there is inconsistent
use of whitespace. This patch tries to address the main
culprits.
Signed-off-by: John Stultz <john.stultz@linaro.org>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Link: http://lkml.kernel.org/r/1342156917-25092-3-git-send-email-john.stultz@linaro.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reason: Update to upstream changes to avoid further conflicts.
Fixup a trivial merge conflict in kernel/time/tick-sched.c
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
In commit 6b43ae8a61, I
introduced a bug that kept the STA_INS or STA_DEL bit
from being cleared from time_status via adjtimex()
without forcing STA_PLL first.
Usually once the STA_INS is set, it isn't cleared
until the leap second is applied, so its unlikely this
affected anyone. However during testing I noticed it
took some effort to cancel a leap second once STA_INS
was set.
Signed-off-by: John Stultz <johnstul@us.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Prarit Bhargava <prarit@redhat.com>
CC: stable@vger.kernel.org # 3.4
Link: http://lkml.kernel.org/r/1342156917-25092-2-git-send-email-john.stultz@linaro.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Pull RCU, perf, and scheduler fixes from Ingo Molnar.
The RCU fix is a revert for an optimization that could cause deadlocks.
One of the scheduler commits (164c33c6ad "sched: Fix fork() error path
to not crash") is correct but not complete (some architectures like Tile
are not covered yet) - the resulting additional fixes are still WIP and
Ingo did not want to delay these pending fixes. See this thread on
lkml:
[PATCH] fork: fix error handling in dup_task()
The perf fixes are just trivial oneliners.
* 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
Revert "rcu: Move PREEMPT_RCU preemption to switch_to() invocation"
* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
perf kvm: Fix segfault with report and mixed guestmount use
perf kvm: Fix regression with guest machine creation
perf script: Fix format regression due to libtraceevent merge
ring-buffer: Fix accounting of entries when removing pages
ring-buffer: Fix crash due to uninitialized new_pages list head
* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
MAINTAINERS/sched: Update scheduler file pattern
sched/nohz: Rewrite and fix load-avg computation -- again
sched: Fix fork() error path to not crash
To finally fix the infamous leap second issue and other race windows
caused by functions which change the offsets between the various time
bases (CLOCK_MONOTONIC, CLOCK_REALTIME and CLOCK_BOOTTIME) we need a
function which atomically gets the current monotonic time and updates
the offsets of CLOCK_REALTIME and CLOCK_BOOTTIME with minimalistic
overhead. The previous patch which provides ktime_t offsets allows us
to make this function almost as cheap as ktime_get() which is going to
be replaced in hrtimer_interrupt().
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Prarit Bhargava <prarit@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: John Stultz <johnstul@us.ibm.com>
Link: http://lkml.kernel.org/r/1341960205-56738-7-git-send-email-johnstul@us.ibm.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
We need to update the hrtimer clock offsets from the hrtimer interrupt
context. To avoid conversions from timespec to ktime_t maintain a
ktime_t based representation of those offsets in the timekeeper. This
puts the conversion overhead into the code which updates the
underlying offsets and provides fast accessible values in the hrtimer
interrupt.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <johnstul@us.ibm.com>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Prarit Bhargava <prarit@redhat.com>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/1341960205-56738-4-git-send-email-johnstul@us.ibm.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
The timekeeping code misses an update of the hrtimer subsystem after a
leap second happened. Due to that timers based on CLOCK_REALTIME are
either expiring a second early or late depending on whether a leap
second has been inserted or deleted until an operation is initiated
which causes that update. Unless the update happens by some other
means this discrepancy between the timekeeping and the hrtimer data
stays forever and timers are expired either early or late.
The reported immediate workaround - $ data -s "`date`" - is causing a
call to clock_was_set() which updates the hrtimer data structures.
See: http://www.sheeri.com/content/mysql-and-leap-second-high-cpu-and-fix
Add the missing clock_was_set() call to update_wall_time() in case of
a leap second event. The actual update is deferred to softirq context
as the necessary smp function call cannot be invoked from hard
interrupt context.
Signed-off-by: John Stultz <johnstul@us.ibm.com>
Reported-by: Jan Engelhardt <jengelh@inai.de>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Prarit Bhargava <prarit@redhat.com>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/1341960205-56738-3-git-send-email-johnstul@us.ibm.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Thanks to Charles Wang for spotting the defects in the current code:
- If we go idle during the sample window -- after sampling, we get a
negative bias because we can negate our own sample.
- If we wake up during the sample window we get a positive bias
because we push the sample to a known active period.
So rewrite the entire nohz load-avg muck once again, now adding
copious documentation to the code.
Reported-and-tested-by: Doug Smythies <dsmythies@telus.net>
Reported-and-tested-by: Charles Wang <muming.wq@gmail.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: stable@kernel.org
Link: http://lkml.kernel.org/r/1340373782.18025.74.camel@twins
[ minor edits ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull core updates (RCU and locking) from Ingo Molnar:
"Most of the diffstat comes from the RCU slow boot regression fixes,
but there's also a debuggability improvements/fixes."
* 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
memblock: Document memblock_is_region_{memory,reserved}()
rcu: Precompute RCU_FAST_NO_HZ timer offsets
rcu: Move RCU_FAST_NO_HZ per-CPU variables to rcu_dynticks structure
rcu: Update RCU_FAST_NO_HZ tracing for lazy callbacks
rcu: RCU_FAST_NO_HZ detection of callback adoption
spinlock: Indicate that a lockup is only suspected
kdump: Execute kmsg_dump(KMSG_DUMP_PANIC) after smp_send_stop()
panic: Make panic_on_oops configurable
The next idle expiry time record and idle sleeps tracking are
statistics that only concern idle.
Since we want the nohz APIs to become usable further idle
context, let's pull up the handling of these statistics to the
callers in idle.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Alessio Igor Bogani <abogani@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Avi Kivity <avi@redhat.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Geoff Levand <geoff@infradead.org>
Cc: Gilad Ben Yossef <gilad@benyossef.com>
Cc: Hakan Akkan <hakanakkan@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Kevin Hilman <khilman@ti.com>
Cc: Max Krasnyansky <maxk@qualcomm.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephen Hemminger <shemminger@vyatta.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Sven-Thorsten Dietrich <thebigcorporation@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Since we want to prepare for making the nohz API to work further
the idle case, we need to pull ts->idle_calls incrementation up to
the callers in idle.
To perform this, we split tick_nohz_stop_sched_tick() in two parts:
a first one that checks if we can really stop the tick for idle,
and another that actually stops it. Then from the callers in idle,
we check if we can stop the tick and only then we increment idle_calls
and finally relay to the nohz API that won't care about these details
anymore.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Alessio Igor Bogani <abogani@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Avi Kivity <avi@redhat.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Geoff Levand <geoff@infradead.org>
Cc: Gilad Ben Yossef <gilad@benyossef.com>
Cc: Hakan Akkan <hakanakkan@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Kevin Hilman <khilman@ti.com>
Cc: Max Krasnyansky <maxk@qualcomm.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephen Hemminger <shemminger@vyatta.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Sven-Thorsten Dietrich <thebigcorporation@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Now that idle and nohz logics are going to be independant each others,
ts->idle_tick becomes too much a biased name to describe the field that
saves the last scheduled tick on top of which we re-calculate the next
tick to schedule when the timer is restarted.
We want to reuse this even to stop the tick outside idle cases. So let's
rename it to some more generic name: ts->last_tick.
This changes a bit the timer list stat export so we need to increase its
version.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Alessio Igor Bogani <abogani@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Avi Kivity <avi@redhat.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Geoff Levand <geoff@infradead.org>
Cc: Gilad Ben Yossef <gilad@benyossef.com>
Cc: Hakan Akkan <hakanakkan@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Kevin Hilman <khilman@ti.com>
Cc: Max Krasnyansky <maxk@qualcomm.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephen Hemminger <shemminger@vyatta.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Sven-Thorsten Dietrich <thebigcorporation@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
When the timer tick fires, it accounts the new jiffy as either part
of system, user or idle time. This is how we record the cputime
statistics.
But when the tick is stopped from the idle task, we still need
to record the number of jiffies spent tickless until we restart
the tick and fall back to traditional tick-based cputime accounting.
To do this, we take a snapshot of jiffies when the tick is stopped
and compute the difference against the new value of jiffies when
the tick is restarted. Then we account this whole difference to
the idle cputime.
However we are preparing to be able to stop the tick from other places
than idle. So this idle time accounting needs to be performed from
the callers of nohz APIs, not from the nohz APIs themselves because
we now want them to be agnostic against places that stop/restart tick.
Therefore, we pull the tickless idle time accounting out of generic
nohz helpers up to idle entry/exit callers.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Alessio Igor Bogani <abogani@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Avi Kivity <avi@redhat.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Geoff Levand <geoff@infradead.org>
Cc: Gilad Ben Yossef <gilad@benyossef.com>
Cc: Hakan Akkan <hakanakkan@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Kevin Hilman <khilman@ti.com>
Cc: Max Krasnyansky <maxk@qualcomm.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephen Hemminger <shemminger@vyatta.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Sven-Thorsten Dietrich <thebigcorporation@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
As we plan to be able to stop the tick outside the idle task, we
need to prepare for separating nohz logic from idle. As a start,
this pulls the idle sleeping time accounting out of the tick
stop/restart API to the callers on idle entry/exit.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Alessio Igor Bogani <abogani@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Avi Kivity <avi@redhat.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Geoff Levand <geoff@infradead.org>
Cc: Gilad Ben Yossef <gilad@benyossef.com>
Cc: Hakan Akkan <hakanakkan@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Kevin Hilman <khilman@ti.com>
Cc: Max Krasnyansky <maxk@qualcomm.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephen Hemminger <shemminger@vyatta.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Sven-Thorsten Dietrich <thebigcorporation@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Merge RCU fixes from Paul E. McKenney:
" This series has four patches, the major point of which is to eliminate
some slowdowns (including boot-time slowdowns) resulting from some
RCU_FAST_NO_HZ changes. The issue with the changes is that posting timers
from the idle loop has no effect if the CPU has entered dyntick-idle
mode because the CPU has already computed its wakeup time, and posting
a timer does not cause it to be recomputed. The short-term fix is for
RCU to precompute the timeout value so that the CPU's calculation is
correct. "
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull leap second timer fix from Thomas Gleixner.
* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
timekeeping: Fix CLOCK_MONOTONIC inconsistency during leapsecond
When a CPU is entering dyntick-idle mode, tick_nohz_stop_sched_tick()
calls rcu_needs_cpu() see if RCU needs that CPU, and, if not, computes the
next wakeup time based on the timer wheels. Only later, when actually
entering the idle loop, rcu_prepare_for_idle() will be invoked. In some
cases, rcu_prepare_for_idle() will post timers to wake the CPU back up.
But all for naught: The next wakeup time for the CPU has already been
computed, and posting a timer afterwards does not force that wakeup
time to be recomputed. This means that rcu_prepare_for_idle()'s have
no effect.
This is not a problem on a busy system because something else will wake
up the CPU soon enough. However, on lightly loaded systems, the CPU
might stay asleep for a considerable length of time. If that CPU has
a callback that the rest of the system is waiting on, the system might
run very slowly or (in theory) even hang.
This commit avoids this problem by having rcu_needs_cpu() give
tick_nohz_stop_sched_tick() an estimate of when RCU will need the CPU
to wake back up, which tick_nohz_stop_sched_tick() takes into account
when programming the CPU's wakeup time. An alternative approach is
for rcu_prepare_for_idle() to use hrtimers instead of normal timers,
but timers are much more efficient than are hrtimers for frequently
and repeatedly posting and cancelling a given timer, which is exactly
what RCU_FAST_NO_HZ does.
Reported-by: Pascal Chapperon <pascal.chapperon@wanadoo.fr>
Reported-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Tested-by: Pascal Chapperon <pascal.chapperon@wanadoo.fr>
Pull scheduler fixes from Ingo Molnar.
* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
sched: Remove NULL assignment of dattr_cur
sched: Remove the last NULL entry from sched_feat_names
sched: Make sched_feat_names const
sched/rt: Fix SCHED_RR across cgroups
sched: Move nr_cpus_allowed out of 'struct sched_rt_entity'
sched: Make sure to not re-read variables after validation
sched: Fix SD_OVERLAP
sched: Don't try allocating memory from offline nodes
sched/nohz: Fix rq->cpu_load calculations some more
sched/x86: Use cpu_llc_shared_mask(cpu) for coregroup_mask
Commit 6b43ae8a61 (ntp: Fix leap-second hrtimer livelock) broke the
leapsecond update of CLOCK_MONOTONIC. The missing leapsecond update to
wall_to_monotonic causes discontinuities in CLOCK_MONOTONIC.
Adjust wall_to_monotonic when NTP inserted a leapsecond.
Reported-by: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Tested-by: Richard Cochran <richardcochran@gmail.com>
Cc: stable@kernel.org
Link: http://lkml.kernel.org/r/1338400497-12420-1-git-send-email-john.stultz@linaro.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Follow up on commit 556061b00 ("sched/nohz: Fix rq->cpu_load[]
calculations") since while that fixed the busy case it regressed the
mostly idle case.
Add a callback from the nohz exit to also age the rq->cpu_load[]
array. This closes the hole where either there was no nohz load
balance pass during the nohz, or there was a 'significant' amount of
idle time between the last nohz balance and the nohz exit.
So we'll update unconditionally from the tick to not insert any
accidental 0 load periods while busy, and we try and catch up from
nohz idle balance and nohz exit. Both these are still prone to missing
a jiffy, but that has always been the case.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: pjt@google.com
Cc: Venkatesh Pallipadi <venki@google.com>
Link: http://lkml.kernel.org/n/tip-kt0trz0apodbf84ucjfdbr1a@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Let the user decide whether power consumption or jitter is the
more important consideration for their machines.
Quoting removal commit af5ab277de:
"Historically, Linux has tried to make the regular timer tick on the
various CPUs not happen at the same time, to avoid contention on
xtime_lock.
Nowadays, with the tickless kernel, this contention no longer happens
since time keeping and updating are done differently. In addition,
this skew is actually hurting power consumption in a measurable way on
many-core systems."
Problems:
- Contrary to the above, systems do encounter contention on both
xtime_lock and RCU structure locks when the tick is synchronized.
- Moderate sized RT systems suffer intolerable jitter due to the tick
being synchronized.
- SGI reports the same for their large systems.
- Fully utilized systems reap no power saving benefit from skew removal,
but do suffer from resulting induced lock contention.
- 0209f649 rcu: limit rcu_node leaf-level fanout
This patch was born to combat lock contention which testing showed
to have been _induced by_ skew removal. Skew the tick, contention
disappeared virtually completely.
Signed-off-by: Mike Galbraith <mgalbraith@suse.de>
Link: http://lkml.kernel.org/r/1336472458.21924.78.camel@marge.simpson.net
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Pull timer updates from Thomas Gleixner.
Various trivial conflict fixups in arch Kconfig due to addition of
unrelated entries nearby. And one slightly more subtle one for sparc32
(new user of GENERIC_CLOCKEVENTS), fixed up as per Thomas.
* 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (31 commits)
timekeeping: Fix a few minor newline issues.
time: remove obsolete declaration
ntp: Fix a stale comment and a few stray newlines.
ntp: Correct TAI offset during leap second
timers: Fixup the Kconfig consolidation fallout
x86: Use generic time config
unicore32: Use generic time config
um: Use generic time config
tile: Use generic time config
sparc: Use: generic time config
sh: Use generic time config
score: Use generic time config
s390: Use generic time config
openrisc: Use generic time config
powerpc: Use generic time config
mn10300: Use generic time config
mips: Use generic time config
microblaze: Use generic time config
m68k: Use generic time config
m32r: Use generic time config
...
When repeating a UTC time value during a leap second (when the UTC
time should be 23:59:60), the TAI timescale should not stop. The kernel
NTP code increments the TAI offset one second too late. This patch fixes
the issue by incrementing the offset during the leap second itself.
Signed-off-by: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Sigh, I missed to check which architecture Kconfig files actually
include the core Kconfig file. There are a few which did not. So we
broke them.
Instead of adding the includes to those, we are better off to move the
include to init/Kconfig like we did already with irqs and others.
This does not change anything for the architectures using the old
style periodic timer mode. It just solves the build wreckage there.
For those architectures which use the clock events infrastructure it
moves the include of the core Kconfig file to "General setup" which is
a way more logical place than having it at random locations specified
by the architecture specific Kconfigs.
Reported-by: Ingo Molnar <mingo@kernel.org>
Cc: Anna-Maria Gleixner <anna-maria@glx-um.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
We really don't want all the arch code defining stuff
over and over.
[ anna-maria: Added missing GENERIC_CMOS_UPDATE switch ]
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Anna-Maria Gleixner <anna-maria@glx-um.de>
Cc: Paul Mundt <lethal@linux-sh.org>
Link: http://lkml.kernel.org/r/1337529587.3208.2.camel@dionysos
Acked-by: Sam Ravnborg <sam@ravnborg.org>
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 <ccross@android.com>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: Android Kernel Team <kernel-team@android.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
During resume, tick_resume_broadcast() programs the broadcast timer in
oneshot mode unconditionally. On the platforms where broadcast timer
is not really required, this will generate spurious broadcast timer
ticks upon resume. For example, on the always running apic timer
platforms with HPET, I see spurious hpet tick once every ~5minutes
(which is the 32-bit hpet counter wraparound time).
Similar to boot time, during resume make the oneshot mode setting of
the broadcast clock event device conditional on the state of active
broadcast users.
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Tested-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Tested-by: svenjoac@gmx.de
Cc: torvalds@linux-foundation.org
Cc: rjw@sisk.pl
Link: http://lkml.kernel.org/r/1334802459.28674.209.camel@sbsiddha-desk.sc.intel.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Santosh found another trap when we avoid to initialize the broadcast
device in the switch_to_oneshot code. The broadcast device might be
still in SHUTDOWN state when we actually need to use it. That
obviously breaks, as set_next_event() is called on a shutdown
device. This did not break on x86, but Suresh analyzed it:
From the review, most likely on Sven's system we are force enabling
the hpet using the pci quirk's method very late. And in this case,
hpet_clockevent (which will be global_clock_event) handler can be
null, specifically as this platform might not be using deeper c-states
and using the reliable APIC timer.
Prior to commit 'fa4da365bc7772c', that handler will be set to
'tick_handle_oneshot_broadcast' when we switch the broadcast timer to
oneshot mode, even though we don't use it. Post commit
'fa4da365bc7772c', we stopped switching the broadcast mode to oneshot
as this is not really needed and his platform's global_clock_event's
handler will remain null. While on my SNB laptop, same is set to
'clockevents_handle_noop' because hpet gets enabled very early. (noop
handler on my platform set when the early enabled hpet timer gets
replaced by the lapic timer).
But the commit 'fa4da365bc7772c' tracked the broadcast timer mode in
the SW as oneshot, even though it didn't touch the HW timer. During
resume however, tick_resume_broadcast() saw the SW broadcast mode as
oneshot and actually programmed the broadcast device also into oneshot
mode. So this triggered the null pointer de-reference after the hpet
wraps around and depending on what the hpet counter is set to. On the
normal platforms where hpet gets enabled early we should be seeing a
spurious interrupt (in my SNB laptop I see one spurious interrupt
after around 5 minutes ;) which is 32-bit hpet counter wraparound
time), but that's a separate issue.
Enforce the mode setting when trying to set an event.
Reported-and-tested-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: torvalds@linux-foundation.org
Cc: svenjoac@gmx.de
Cc: rjw@sisk.pl
Link: http://lkml.kernel.org/r/alpine.LFD.2.02.1204181723350.2542@ionos
Sven Joachim reported, that suspend/resume on rc3 trips over a NULL
pointer dereference. Linus spotted the clockevent handler being NULL.
commit fa4da365b(clockevents: tTack broadcast device mode change in
tick_broadcast_switch_to_oneshot()) tried to fix a problem with the
broadcast device setup, which was introduced in commit 77b0d60c5(
clockevents: Leave the broadcast device in shutdown mode when not
needed).
The initial commit avoided to set up the broadcast device when no
broadcast request bits were set, but that left the broadcast device
disfunctional. In consequence deep idle states which need the
broadcast device were not woken up.
commit fa4da365b tried to fix that by initializing the state of the
broadcast facility, but that missed the fact, that nothing initializes
the event handler and some other state of the underlying clock event
device.
The fix is to revert both commits and make only the mode setting of
the clock event device conditional on the state of active broadcast
users.
That initializes everything except the low level device mode, but this
happens when the broadcast functionality is invoked by deep idle.
Reported-and-tested-by: Sven Joachim <svenjoac@gmx.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Link: http://lkml.kernel.org/r/alpine.LFD.2.02.1204181205540.2542@ionos
In the commit 77b0d60c5a,
"clockevents: Leave the broadcast device in shutdown mode when not needed",
we were bailing out too quickly in tick_broadcast_switch_to_oneshot(),
with out tracking the broadcast device mode change to 'TICKDEV_MODE_ONESHOT'.
This breaks the platforms which need broadcast device oneshot services during
deep idle states. tick_broadcast_oneshot_control() thinks that it is
in periodic mode and fails to take proper decisions based on the
CLOCK_EVT_NOTIFY_BROADCAST_[ENTER, EXIT] notifications during deep
idle entry/exit.
Fix this by tracking the broadcast device mode as 'TICKDEV_MODE_ONESHOT',
before leaving the broadcast HW device in shutdown mode if there are no active
requests for the moment.
Reported-and-tested-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: johnstul@us.ibm.com
Link: http://lkml.kernel.org/r/1334011304.12400.81.camel@sbsiddha-desk.sc.intel.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Fix tick_nohz_restart() to not use a stale ktime_t "now" value when
calling tick_do_update_jiffies64(now).
If we reach this point in the loop it means that we crossed a tick
boundary since we grabbed the "now" timestamp, so at this point "now"
refers to a time in the old jiffy, so using the old value for "now" is
incorrect, and is likely to give us a stale jiffies value.
In particular, the first time through the loop the
tick_do_update_jiffies64(now) call is always a no-op, since the
caller, tick_nohz_restart_sched_tick(), will have already called
tick_do_update_jiffies64(now) with that "now" value.
Note that tick_nohz_stop_sched_tick() already uses the correct
approach: when we notice we cross a jiffy boundary, grab a new
timestamp with ktime_get(), and *then* update jiffies.
Signed-off-by: Neal Cardwell <ncardwell@google.com>
Cc: Ben Segall <bsegall@google.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/1332875377-23014-1-git-send-email-ncardwell@google.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This option has been selected from arch code as it was assumed that
it's necessary to support oneshot mode clockevent devices. But it's
just a core internal helper to compile tick-oneshot.c if NOHZ or
HIG_RES_TIMERS are selected.
Reported-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Pull timer core updates from Thomas Gleixner.
* 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
ia64: vsyscall: Add missing paranthesis
alarmtimer: Don't call rtc_timer_init() when CONFIG_RTC_CLASS=n
x86: vdso: Put declaration before code
x86-64: Inline vdso clock_gettime helpers
x86-64: Simplify and optimize vdso clock_gettime monotonic variants
kernel-time: fix s/then/than/ spelling errors
time: remove no_sync_cmos_clock
time: Avoid scary backtraces when warning of > 11% adj
alarmtimer: Make sure we initialize the rtctimer
ntp: Fix leap-second hrtimer livelock
x86, tsc: Skip refined tsc calibration on systems with reliable TSC
rtc: Provide flag for rtc devices that don't support UIE
ia64: vsyscall: Use seqcount instead of seqlock
x86: vdso: Use seqcount instead of seqlock
x86: vdso: Remove bogus locking in update_vsyscall_tz()
time: Remove bogus comments
time: Fix change_clocksource locking
time: x86: Fix race switching from vsyscall to non-vsyscall clock
rtc_timer_init() is not available when CONFIG_RTC_CLASS=n. Provide a
proper wrapper in the RTC section of alarmtimer.c
Reported-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: John Stultz <john.stultz@linaro.org>
Use than for comparisons, like more than.
CC: John Stultz <john.stultz@linaro.org>
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Commit 9863c90f68 (x86, vmware: Remove
deprecated VMI kernel support) removed the only place which set
no_sync_cmos_clock. Since that commit, this variable is never set.
Signed-off-by: Cesar Eduardo Barros <cesarb@cesarb.net>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Folks have been getting a number of warnings about time
adjustments > 11%. The WARN_ON leaves a big useless backtrace
so this patch removes it for a printk_once().
I'm still working to narrow down the cause of the > 11% adjustment.
Signed-off-by: John Stultz <john.stultz@linaro.org>
jonghwan Choi reported seeing warnings with the alarmtimer
code at suspend/resume time, and pointed out that the
rtctimer isn't being properly initialized.
This patch corrects this issue.
Reported-by: jonghwan Choi <jhbird.choi@gmail.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Pull input subsystem updates from Dmitry Torokhov:
"- we finally merged driver for USB version of Synaptics touchpads
(I guess most commonly found in IBM/Lenovo keyboard/touchpad combo);
- a bunch of new drivers for embedded platforms (Cypress
touchscreens, DA9052 OnKey, MAX8997-haptic, Ilitek ILI210x
touchscreens, TI touchscreen);
- input core allows clients to specify desired clock source for
timestamps on input events (EVIOCSCLOCKID ioctl);
- input core allows querying state of all MT slots for given event
code via EVIOCGMTSLOTS ioctl;
- various driver fixes and improvements."
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input: (45 commits)
Input: ili210x - add support for Ilitek ILI210x based touchscreens
Input: altera_ps2 - use of_match_ptr()
Input: synaptics_usb - switch to module_usb_driver()
Input: convert I2C drivers to use module_i2c_driver()
Input: convert SPI drivers to use module_spi_driver()
Input: omap4-keypad - move platform_data to <linux/platform_data>
Input: kxtj9 - who_am_i check value and initial data rate fixes
Input: add driver support for MAX8997-haptic
Input: tegra-kbc - revise device tree support
Input: of_keymap - add device tree bindings for simple key matrices
Input: wacom - fix physical size calculation for 3rd-gen Bamboo
Input: twl4030-vibra - really switch from #if to #ifdef
Input: hp680_ts_input - ensure arguments to request_irq and free_irq are compatible
Input: max8925_onkey - avoid accessing input device too early
Input: max8925_onkey - allow to be used as a wakeup source
Input: atmel-wm97xx - convert to dev_pm_ops
Input: atmel-wm97xx - set driver owner
Input: add cyttsp touchscreen maintainer entry
Input: cyttsp - remove useless checks in cyttsp_probe()
Input: usbtouchscreen - add support for Data Modul EasyTouch TP 72037
...
Since commit 7dffa3c673 the ntp
subsystem has used an hrtimer for triggering the leapsecond
adjustment. However, this can cause a potential livelock.
Thomas diagnosed this as the following pattern:
CPU 0 CPU 1
do_adjtimex()
spin_lock_irq(&ntp_lock);
process_adjtimex_modes(); timer_interrupt()
process_adj_status(); do_timer()
ntp_start_leap_timer(); write_lock(&xtime_lock);
hrtimer_start(); update_wall_time();
hrtimer_reprogram(); ntp_tick_length()
tick_program_event() spin_lock(&ntp_lock);
clockevents_program_event()
ktime_get()
seq = req_seqbegin(xtime_lock);
This patch tries to avoid the problem by reverting back to not using
an hrtimer to inject leapseconds, and instead we handle the leapsecond
processing in the second_overflow() function.
The downside to this change is that on systems that support highres
timers, the leap second processing will occur on a HZ tick boundary,
(ie: ~1-10ms, depending on HZ) after the leap second instead of
possibly sooner (~34us in my tests w/ x86_64 lapic).
This patch applies on top of tip/timers/core.
CC: Sasha Levin <levinsasha928@gmail.com>
CC: Thomas Gleixner <tglx@linutronix.de>
Reported-by: Sasha Levin <levinsasha928@gmail.com>
Diagnoised-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Sasha Levin <levinsasha928@gmail.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
change_clocksource() fails to grab locks or call timekeeping_update(),
which leaves a race window for time inconsistencies.
This adds proper locking and a call to timekeeping_update() to fix this.
CC: Andy Lutomirski <luto@amacapital.net>
CC: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>
