[PATCH tip/core/rcu 0/17] Torture-test updates for v4.21/v5.0

[Paul E. McKenney]

Hello!

This series contains torture-test updates:

1.	Add call_rcu() flooding forward-progress tests.  If people
	are going to be seeing forward-progress issues with RCU, then
	rcutorture needs to up its game.

2.	Bring any extra CPUs online during kernel startup.

3.	Remove cbflood facility due to its being obsoleted by flooding
	forward-progress tests.

4.	Break up too-long rcu_torture_fwd_prog() function.

5.	Affinity forward-progress test to avoid housekeeping CPUs.

6.	Remove unnecessary "ret" variables, courtesy of Pierce Griffiths.

7.	Prepare for asynchronous access to rcu_fwd_startat.

8.	Dump grace-period diagnostics upon forward-progress OOM.

9.	Account for nocb-CPU callback counts in RCU CPU stall warnings.

10.	Print per-CPU callback counts for forward-progress failures.

11.	Print GP age upon forward-progress failure.

12.	Print histogram of CB invocation at OOM time.

13.	Print time since GP end upon forward-progress failure.

14.	Print forward-progress test age upon failure.

15.	Recover from OOM during forward-progress tests.

16.	Use 100ms buckets for forward-progress callback histograms.

17.	Don't do forward-progress testing of known-bad "RCU" variants.

							Thanx, Paul

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

 Documentation/admin-guide/kernel-parameters.txt |   18 
 kernel/rcu/rcu.h                                |    4 
 kernel/rcu/rcutorture.c                         |  603 ++++++++++++++----------
 kernel/rcu/tree.c                               |   64 ++
 kernel/rcu/tree.h                               |    3 
 kernel/rcu/tree_plugin.h                        |   35 +
 kernel/torture.c                                |   34 -
 7 files changed, 484 insertions(+), 277 deletions(-)