linux/kernel/time, branch v3.5

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

2012-07-18T17:36:02Z

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

timekeeping: Add missing update call in timekeeping_resume()

2012-07-16T17:02:17Z

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

ntp: Fix STA_INS/DEL clearing bug

2012-07-15T07:48:49Z

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

Merge branches 'core-urgent-for-linus', 'perf-urgent-for-linus' and 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2012-07-14T18:16:24Z

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

timekeeping: Provide hrtimer update function

2012-07-11T21:34:39Z

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

timekeeping: Maintain ktime_t based offsets for hrtimers

2012-07-11T21:34:38Z

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

timekeeping: Fix leapsecond triggered load spike issue

2012-07-11T21:34:37Z

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 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

sched/nohz: Rewrite and fix load-avg computation -- again

2012-07-05T18:58:13Z

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

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

2012-06-15T23:52:35Z

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

Merge branch 'rcu/urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into core/urgent

2012-06-11T08:30:23Z

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