23 Jul, 2012
2 commits
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Pull timer core changes from Ingo Molnar:
"Continued cleanups of the core time and NTP code, plus more nohz work
preparing for tick-less userspace execution."* 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
time: Rework timekeeping functions to take timekeeper ptr as argument
time: Move xtime_nsec adjustment underflow handling timekeeping_adjust
time: Move arch_gettimeoffset() usage into timekeeping_get_ns()
time: Refactor accumulation of nsecs to secs
time: Condense timekeeper.xtime into xtime_sec
time: Explicitly use u32 instead of int for shift values
time: Whitespace cleanups per Ingo%27s requests
nohz: Move next idle expiry time record into idle logic area
nohz: Move ts->idle_calls incrementation into strict idle logic
nohz: Rename ts->idle_tick to ts->last_tick
nohz: Make nohz API agnostic against idle ticks cputime accounting
nohz: Separate idle sleeping time accounting from nohz logic
timers: Improve get_next_timer_interrupt()
timers: Add accounting of non deferrable timers
timers: Consolidate base->next_timer update
timers: Create detach_if_pending() and use it -
Pull RCU changes from Ingo Molnar:
"Quoting from Paul, the major features of this series are:1. Preventing latency spikes of more than 200 microseconds for
kernels built with NR_CPUS=4096, which is reportedly becoming the
default for some distros. This is a first step, as it does not
help with systems that actually -have- 4096 CPUs (work on this case
is in progress, but is not yet ready for mainline).This category also includes improving concurrency of rcu_barrier(),
placed here due to conflicts. Posted to LKML at:https://lkml.org/lkml/2012/6/22/381
Note that patches 18-22 of that series have been defered to 3.7, as
they have not yet proven themselves to be mainline-ready (and yes,
these are the ones intended to get rid of RCU's latency spikes for
systems that actually have 4096 CPUs).2. Updates to documentation and rcutorture fixes, the latter category
including improvements to rcu_barrier() testing. Posted to LKML athttp://lkml.indiana.edu/hypermail/linux/kernel/1206.1/04094.html.
3. Miscellaneous fixes posted to LKML at:
https://lkml.org/lkml/2012/6/22/500
with the exception of the last commit, which was posted here:
http://www.gossamer-threads.com/lists/linux/kernel/1561830
4. RCU_FAST_NO_HZ fixes and improvements. Posted to LKML at:
http://lkml.indiana.edu/hypermail/linux/kernel/1206.1/00006.html
http://www.gossamer-threads.com/lists/linux/kernel/1561833The first four patches of the first series went into 3.5 to fix a
regression.5. Code-style fixes. These were posted to LKML at
http://lkml.indiana.edu/hypermail/linux/kernel/1205.2/01180.html
http://lkml.indiana.edu/hypermail/linux/kernel/1205.2/01181.html"* 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (48 commits)
rcu: Fix broken strings in RCU's source code.
rcu: Fix code-style issues involving "else"
rcu: Introduce check for callback list/count mismatch
rcu: Make RCU_FAST_NO_HZ respect nohz= boot parameter
rcu: Fix qlen_lazy breakage
rcu: Round FAST_NO_HZ lazy timeout to nearest second
rcu: The rcu_needs_cpu() function is not a quiescent state
rcu: Dump only the current CPU's buffers for idle-entry/exit warnings
rcu: Add check for CPUs going offline with callbacks queued
rcu: Disable preemption in rcu_blocking_is_gp()
rcu: Prevent uninitialized string in RCU CPU stall info
rcu: Fix rcu_is_cpu_idle() #ifdef in TINY_RCU
rcu: Split RCU core processing out of __call_rcu()
rcu: Prevent __call_rcu() from invoking RCU core on offline CPUs
rcu: Make __call_rcu() handle invocation from idle
rcu: Remove function versions of __kfree_rcu and __is_kfree_rcu_offset
rcu: Consolidate tree/tiny __rcu_read_{,un}lock() implementations
rcu: Remove return value from rcu_assign_pointer()
key: Remove extraneous parentheses from rcu_assign_keypointer()
rcu: Remove return value from RCU_INIT_POINTER()
...
19 Jul, 2012
1 commit
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One more time/ntp fix pulled from Ingo Molnar.
* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
ntp: Fix STA_INS/DEL clearing bug
18 Jul, 2012
1 commit
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Resolve semantic conflict in kernel/time/timekeeping.c.
Signed-off-by: Ingo Molnar
17 Jul, 2012
1 commit
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The leap second rework unearthed another issue of inconsistent data.
On timekeeping_resume() the timekeeper data is updated, but nothing
calls timekeeping_update(), so now the update code in the timer
interrupt sees stale values.This has been the case before those changes, but then the timer
interrupt was using stale data as well so this went unnoticed for quite
some time.Add the missing update call, so all the data is consistent everywhere.
Reported-by: Andreas Schwab
Reported-and-tested-by: "Rafael J. Wysocki"
Reported-and-tested-by: Martin Steigerwald
Cc: LKML
Cc: Linux PM list
Cc: John Stultz
Cc: Ingo Molnar
Cc: Peter Zijlstra ,
Cc: Prarit Bhargava
Cc: stable@vger.kernel.org
Signed-off-by: Thomas Gleixner
Signed-off-by: John Stultz
Signed-off-by: Linus Torvalds
15 Jul, 2012
10 commits
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As part of cleaning up the timekeeping code, this patch converts
a number of internal functions to takei a timekeeper ptr as an
argument, so that the internal functions don't access the global
timekeeper structure directly. This allows for further optimizations
to reduce lock hold time later.This patch has been updated to include more consistent usage of the
timekeeper value, by making sure it is always passed as a argument
to non top-level functions.Signed-off-by: John Stultz
Reviewed-by: Ingo Molnar
Cc: Peter Zijlstra
Cc: Richard Cochran
Cc: Prarit Bhargava
Link: http://lkml.kernel.org/r/1342156917-25092-9-git-send-email-john.stultz@linaro.org
Signed-off-by: Thomas Gleixner -
When we make adjustments speeding up the clock, its possible
for xtime_nsec to underflow. We already handle this properly,
but we do so from update_wall_time() instead of the more logical
timekeeping_adjust(), where the possible underflow actually
occurs.Thus, move the correction logic to the timekeeping_adjust, which
is the function that causes the issue. Making update_wall_time()
more readable.Signed-off-by: John Stultz
Reviewed-by: Ingo Molnar
Cc: Peter Zijlstra
Cc: Richard Cochran
Cc: Prarit Bhargava
Link: http://lkml.kernel.org/r/1342156917-25092-8-git-send-email-john.stultz@linaro.org
Signed-off-by: Thomas Gleixner -
Since we call arch_gettimeoffset() in all the accessor
functions, move arch_gettimeoffset() calls into
timekeeping_get_ns() and timekeeping_get_ns_raw() to simplify
the code.This also makes the code easier to maintain as we don't have to
worry about forgetting the arch_gettimeoffset() as has happened
in the past.Signed-off-by: John Stultz
Reviewed-by: Ingo Molnar
Cc: Peter Zijlstra
Cc: Richard Cochran
Cc: Prarit Bhargava
Link: http://lkml.kernel.org/r/1342156917-25092-7-git-send-email-john.stultz@linaro.org
Signed-off-by: Thomas Gleixner -
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
Reviewed-by: Ingo Molnar
Cc: Peter Zijlstra
Cc: Richard Cochran
Cc: Prarit Bhargava
Link: http://lkml.kernel.org/r/1342156917-25092-6-git-send-email-john.stultz@linaro.org
Signed-off-by: Thomas Gleixner -
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
Reviewed-by: Ingo Molnar
Cc: Peter Zijlstra
Cc: Richard Cochran
Cc: Prarit Bhargava
Link: http://lkml.kernel.org/r/1342156917-25092-5-git-send-email-john.stultz@linaro.org
Signed-off-by: Thomas Gleixner -
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
Reviewed-by: Ingo Molnar
Cc: Peter Zijlstra
Cc: Richard Cochran
Cc: Prarit Bhargava
Link: http://lkml.kernel.org/r/1342156917-25092-4-git-send-email-john.stultz@linaro.org
Signed-off-by: Thomas Gleixner -
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
Reviewed-by: Ingo Molnar
Cc: Peter Zijlstra
Cc: Richard Cochran
Cc: Prarit Bhargava
Link: http://lkml.kernel.org/r/1342156917-25092-3-git-send-email-john.stultz@linaro.org
Signed-off-by: Thomas Gleixner -
Reason: Update to upstream changes to avoid further conflicts.
Fixup a trivial merge conflict in kernel/time/tick-sched.cSigned-off-by: Thomas Gleixner
-
In commit 6b43ae8a619d17c4935c3320d2ef9e92bdeed05d, 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
Cc: Ingo Molnar
Cc: Peter Zijlstra
Cc: Richard Cochran
Cc: Prarit Bhargava
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 -
…t-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
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 (164c33c6adee "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
12 Jul, 2012
3 commits
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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
Reviewed-by: Ingo Molnar
Acked-by: Peter Zijlstra
Acked-by: Prarit Bhargava
Cc: stable@vger.kernel.org
Signed-off-by: John Stultz
Link: http://lkml.kernel.org/r/1341960205-56738-7-git-send-email-johnstul@us.ibm.com
Signed-off-by: Thomas Gleixner -
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
Signed-off-by: John Stultz
Reviewed-by: Ingo Molnar
Acked-by: Peter Zijlstra
Acked-by: Prarit Bhargava
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 -
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-fixAdd 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
Reported-by: Jan Engelhardt
Reviewed-by: Ingo Molnar
Acked-by: Peter Zijlstra
Acked-by: Prarit Bhargava
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
06 Jul, 2012
1 commit
-
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
Reported-and-tested-by: Charles Wang
Signed-off-by: Peter Zijlstra
Cc: Linus Torvalds
Cc: Andrew Morton
Cc: stable@kernel.org
Link: http://lkml.kernel.org/r/1340373782.18025.74.camel@twins
[ minor edits ]
Signed-off-by: Ingo Molnar
03 Jul, 2012
1 commit
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If the nohz= boot parameter disables nohz, then RCU_FAST_NO_HZ needs to
also disable itself. This commit therefore checks for tick_nohz_enabled
being zero, disabling rcu_prepare_for_idle() if so. This commit assumes
that tick_nohz_enabled can change at runtime: If this is not the case,
then a simpler approach suffices.Signed-off-by: Paul E. McKenney
Signed-off-by: Paul E. McKenney
16 Jun, 2012
1 commit
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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
12 Jun, 2012
5 commits
-
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
Cc: Alessio Igor Bogani
Cc: Andrew Morton
Cc: Avi Kivity
Cc: Chris Metcalf
Cc: Christoph Lameter
Cc: Daniel Lezcano
Cc: Geoff Levand
Cc: Gilad Ben Yossef
Cc: Hakan Akkan
Cc: Ingo Molnar
Cc: Kevin Hilman
Cc: Max Krasnyansky
Cc: Paul E. McKenney
Cc: Peter Zijlstra
Cc: Stephen Hemminger
Cc: Steven Rostedt
Cc: Sven-Thorsten Dietrich
Cc: Thomas Gleixner -
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
Cc: Alessio Igor Bogani
Cc: Andrew Morton
Cc: Avi Kivity
Cc: Chris Metcalf
Cc: Christoph Lameter
Cc: Daniel Lezcano
Cc: Geoff Levand
Cc: Gilad Ben Yossef
Cc: Hakan Akkan
Cc: Ingo Molnar
Cc: Kevin Hilman
Cc: Max Krasnyansky
Cc: Paul E. McKenney
Cc: Peter Zijlstra
Cc: Stephen Hemminger
Cc: Steven Rostedt
Cc: Sven-Thorsten Dietrich
Cc: Thomas Gleixner -
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
Cc: Alessio Igor Bogani
Cc: Andrew Morton
Cc: Avi Kivity
Cc: Chris Metcalf
Cc: Christoph Lameter
Cc: Daniel Lezcano
Cc: Geoff Levand
Cc: Gilad Ben Yossef
Cc: Hakan Akkan
Cc: Ingo Molnar
Cc: Kevin Hilman
Cc: Max Krasnyansky
Cc: Paul E. McKenney
Cc: Peter Zijlstra
Cc: Stephen Hemminger
Cc: Steven Rostedt
Cc: Sven-Thorsten Dietrich
Cc: Thomas Gleixner -
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
Cc: Alessio Igor Bogani
Cc: Andrew Morton
Cc: Avi Kivity
Cc: Chris Metcalf
Cc: Christoph Lameter
Cc: Daniel Lezcano
Cc: Geoff Levand
Cc: Gilad Ben Yossef
Cc: Hakan Akkan
Cc: Ingo Molnar
Cc: Kevin Hilman
Cc: Max Krasnyansky
Cc: Paul E. McKenney
Cc: Peter Zijlstra
Cc: Stephen Hemminger
Cc: Steven Rostedt
Cc: Sven-Thorsten Dietrich
Cc: Thomas Gleixner -
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
Cc: Alessio Igor Bogani
Cc: Andrew Morton
Cc: Avi Kivity
Cc: Chris Metcalf
Cc: Christoph Lameter
Cc: Daniel Lezcano
Cc: Geoff Levand
Cc: Gilad Ben Yossef
Cc: Hakan Akkan
Cc: Ingo Molnar
Cc: Kevin Hilman
Cc: Max Krasnyansky
Cc: Paul E. McKenney
Cc: Peter Zijlstra
Cc: Stephen Hemminger
Cc: Steven Rostedt
Cc: Sven-Thorsten Dietrich
Cc: Thomas Gleixner
11 Jun, 2012
1 commit
-
…ck/linux-rcu into core/urgent
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>
09 Jun, 2012
1 commit
-
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
07 Jun, 2012
1 commit
-
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
Reported-by: Heiko Carstens
Signed-off-by: Paul E. McKenney
Signed-off-by: Paul E. McKenney
Tested-by: Heiko Carstens
Tested-by: Pascal Chapperon
06 Jun, 2012
1 commit
-
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
05 Jun, 2012
1 commit
-
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
Signed-off-by: John Stultz
Tested-by: Richard Cochran
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
30 May, 2012
1 commit
-
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
Cc: pjt@google.com
Cc: Venkatesh Pallipadi
Link: http://lkml.kernel.org/n/tip-kt0trz0apodbf84ucjfdbr1a@git.kernel.org
Signed-off-by: Ingo Molnar
25 May, 2012
4 commits
-
commit 5307c95 (tick: Add tick skew boot option) broke the
!CONFIG_HIGH_RES_TIMERS build.Move the boot option parsing into the CONFIG_HIGH_RES_TIMERS section.
Reported-by: Ingo Molnar
Signed-off-by: Thomas Gleixner
Cc: Mike Galbraith -
Make clockevents_config() into a global symbol to allow it to be used
by compiled-in clockevent drivers. This is needed by drivers that want
to update the timer frequency after registration time.Signed-off-by: Magnus Damm
Tested-by: Simon Horman
Cc: arnd@arndb.de
Cc: johnstul@us.ibm.com
Cc: rjw@sisk.pl
Cc: lethal@linux-sh.org
Cc: gregkh@linuxfoundation.org
Cc: olof@lixom.net
Cc: Magnus Damm
Link: http://lkml.kernel.org/r/20120509143934.27521.46553.sendpatchset@w520
Signed-off-by: Thomas Gleixner -
Let the user decide whether power consumption or jitter is the
more important consideration for their machines.Quoting removal commit af5ab277ded04bd9bc6b048c5a2f0e7d70ef0867:
"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
Link: http://lkml.kernel.org/r/1336472458.21924.78.camel@marge.simpson.net
Signed-off-by: Thomas Gleixner -
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
...
22 May, 2012
4 commits
-
Fix a few minor newline issues.
Signed-off-by: Richard Cochran
Signed-off-by: John Stultz -
Signed-off-by: Richard Cochran
Signed-off-by: John Stultz -
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
Signed-off-by: John Stultz
