tick/nohz updates

Various updates for the timer/nohz side.

* Two fixes (maybe 01/10 deserves a stable tag, I should check)

* A Kconfig help change

* A debug check while enqueuing timers when the tick is stopped in idle.

* The rest is noise reduction for full nohz ("tick/nohz: Kick only _queued_ task whose tick dependency is updated").
It relies on the fact that p->on_rq is never set to anything else than TASK_ON_RQ_QUEUED while the task is running on a CPU, the only relevant exception being the task dequeuing itself on schedule().
I haven't found issues in my modest reviews of deactivate_task() callers but I lost my headlamp while visiting fair's sched entity dequeuing and throttling (had to find my way back in the dark again).

So please double check the last patch.

git://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux-dynticks.git
timers/nohz

HEAD: e469edfa00f97e5ec5d31fe31d3aef0a5c9bd607

Thanks,
Frederic
---

Frederic Weisbecker (5):
tick/nohz: Add tick_nohz_full_this_cpu()
tick/nohz: Remove superflous check for CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
timer: Report ignored local enqueue in nohz mode
tick/nohz: Update nohz_full Kconfig help
tick/nohz: Only wakeup a single target cpu when kicking a task

Marcelo Tosatti (2):
tick/nohz: Change signal tick dependency to wakeup CPUs of member tasks tick/nohz: Kick only _queued_ task whose tick dependency is updated

Yunfeng Ye (2):
tick/nohz: Conditionally restart tick on idle exit tick/nohz: Update idle_exittime on actual idle exit

Zhou Ti (x2019cwm) (1):
tick/nohz: Prevent tick_nohz_get_sleep_length() from returning negative value

 include/linux/sched.h          |   2 +
 include/linux/tick.h           |  19 ++++--
 kernel/sched/core.c            |  25 +++++++-
 kernel/time/Kconfig            |  11 ++--
 kernel/time/posix-cpu-timers.c |   4 +-
 kernel/time/tick-sched.c       | 134 +++++++++++++++++++++++++++++------------
 6 files changed, 142 insertions(+), 53 deletions(-)