[PATCH tip/core/rcu 0/10] Forward-progress changes for v4.20/v5.0

[PATCH tip/core/rcu 0/10] Forward-progress changes for v4.20/v5.0

[Paul E. McKenney]

Hello!

This series includes changes that improve RCU's forward-progress
guarantees for normal grace periods, with a few stray RCU-consolidation
cleanups thrown in for good measure.

1.	Make need_resched() respond to urgent RCU-QS needs.

2.	Provide improved interrupt-from-idle check in rcu_check_callbacks().

3.	Make rcutorture dump out the reader protection sequence when
	an RCU failures or close calls occurs.

4.	Motivate Tiny RCU forward progress.

5.	Eliminate ->rcu_qs_ctr from the rcu_dynticks structure on account
	of its no longer being used.  And let that be a lesson to the
	rest of that structure's fields!!!

6.	Provide functions for determining if call_rcu() has been invoked
	for debugging purposes by the users of call_rcu().

7.	Compute jiffies_till_sched_qs from other kernel parameters,
	because one size simply does not fit all.

8.	More aggressively enlist scheduler aid for nohz_full CPUs.
	After all, they might never see a scheduler-clock interrupt.

9.	Avoid resched_cpu() when rescheduling the current CPU.

10.	Convert "1UL << x" to "BIT(x)" to save a few characters.

							Thanx, Paul

------------------------------------------------------------------------

 Documentation/admin-guide/kernel-parameters.txt |    9 +
 include/linux/rcupdate.h                        |   40 +++++
 include/trace/events/rcu.h                      |    5 
 kernel/rcu/rcu.h                                |    5 
 kernel/rcu/rcutorture.c                         |  119 +++++++++++++---
 kernel/rcu/tiny.c                               |    6 
 kernel/rcu/tree.c                               |  171 ++++++++++++++----------
 kernel/rcu/tree.h                               |    6 
 kernel/rcu/tree_exp.h                           |   17 +-
 kernel/rcu/tree_plugin.h                        |   14 +
 10 files changed, 280 insertions(+), 112 deletions(-)