[PATCH rcu 0/16 Lazy call_rcu() updates for v6.2

[Paul E. McKenney]

Hello!

This series provides energy efficiency for nearly-idle systems by making
call_rcu() more lazy.  Several NOCB changes come along for the ride:

1.	Simplify rcu_init_nohz() cpumask handling, courtesy of Zhen Lei.

2.	Fix late wakeup when flush of bypass cblist happens, courtesy of
	"Joel Fernandes (Google)".

3.	Fix missing nocb gp wake on rcu_barrier(), courtesy of Frederic
	Weisbecker.

4.	Make call_rcu() lazy to save power, courtesy of "Joel Fernandes
	(Google)".

5.	Refactor code a bit in rcu_nocb_do_flush_bypass(), courtesy of
	"Joel Fernandes (Google)".

6.	Shrinker for lazy rcu, courtesy of Vineeth Pillai.

7.	Add laziness and kfree tests, courtesy of "Joel Fernandes
	(Google)".

8.	percpu-refcount: Use call_rcu_flush() for atomic switch, courtesy
	of "Joel Fernandes (Google)".

9.	Use call_rcu_flush() instead of call_rcu, courtesy of "Joel
	Fernandes (Google)".

10.	Use call_rcu_flush() for async reader test, courtesy of "Joel
	Fernandes (Google)".

11.	Use call_rcu_flush() where needed, courtesy of "Joel Fernandes
	(Google)".

12.	scsi/scsi_error: Use call_rcu_flush() instead of call_rcu(),
	courtesy of Uladzislau Rezki.

13.	Make queue_rcu_work() use call_rcu_flush(), courtesy of Uladzislau
	Rezki.

14.	Use call_rcu_flush() instead of call_rcu(), courtesy of "Joel
	Fernandes (Google)".

15.	Use call_rcu_flush() for dst_release(), courtesy of "Joel
	Fernandes (Google)".

16.	devinet: Reduce refcount before grace period, courtesy of Eric
	Dumazet.

Changes since v1:

o	Add more adjustments to avoid excessive laziness (#15 and
	#16 above).

o	Get appropriate Cc lines onto non-RCU patches.

https://lore.kernel.org/all/20221019225138.GA2499943@paulmck-ThinkPad-P17-Gen-1/

						Thanx, Paul

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

 b/drivers/scsi/scsi_error.c |    2 
 b/include/linux/rcupdate.h  |    9 +
 b/kernel/rcu/Kconfig        |    8 +
 b/kernel/rcu/rcu.h          |    8 +
 b/kernel/rcu/rcuscale.c     |   67 +++++++++++-
 b/kernel/rcu/rcutorture.c   |   16 +-
 b/kernel/rcu/sync.c         |    2 
 b/kernel/rcu/tiny.c         |    2 
 b/kernel/rcu/tree.c         |   11 +
 b/kernel/rcu/tree.h         |    1 
 b/kernel/rcu/tree_exp.h     |    2 
 b/kernel/rcu/tree_nocb.h    |   34 +-----
 b/kernel/workqueue.c        |    2 
 b/lib/percpu-refcount.c     |    3 
 b/net/core/dst.c            |    2 
 b/net/ipv4/devinet.c        |   19 +--
 b/net/rxrpc/conn_object.c   |    2 
 kernel/rcu/rcuscale.c       |    2 
 kernel/rcu/tree.c           |  129 +++++++++++++++--------
 kernel/rcu/tree.h           |   11 +
 kernel/rcu/tree_nocb.h      |  243 ++++++++++++++++++++++++++++++++++++--------
 21 files changed, 434 insertions(+), 141 deletions(-)