[PATCH tip/core/rcu 0/17] Torture-test changes for v4.20/v5.0

[Paul E. McKenney]

Hello!

This series contains torture-test changes that can be reasonably
separated from the RCU flavor consolidation and cleanup:

1.	Stop overwriting Make.out file with obsolete version.

2.	Force occasional reader waits to increase the probability
	of quiescent states interacting with RCU's scheduler hooks.

3-4.	Warn on bad torture type for built-in tests.

5.	Remove TREE06 and TREE08 from the default test list, as they
	are redundant after RCU flavor consolidation.

6.	Add RCU-reader forward-progress tests for RCU grace periods.

7.	Also use grace-period sequence numbers to judge forward progress.

8.	Avoid forward-progress no-test complaint if too few
	forward-progress tries.

9.	Vary forward-progress test interval in order to exercise RCU's
	varied forward-progress mechanisms.

10.	Add self-propagating callback to forward-progress testing in
	order to ensure that there is a reason for grace periods to
	exist in the first place, let alone make forward progress.

11.	Increase rcu_read_delay() longdelay_ms in order to exercise
	RCU's forward-progress machinery that kicks into gear at
	about 100 milliseconds into the grace period.

12.	Limit reader duration if irq or bh disabled to avoid triggering
	-rt bh-disabling complaints.

13.	Reduce priority of forward-progress testing for !SMP kernels
	and for PREEMPT kernels without RCU priority boosting.

14.	Adjust number of reader kthreads per CPU-hotplug operations.
	After all, having 32 readers is a great thing for a 32-CPU
	system, but not so much if 31 of the CPUs has been offlined.

15.	Print forward-progress test interval on error.

16.	Check grace-period completion at stutter end:  If the system is
	idle, grace periods should complete quickly.

17.	Maintain self-propagating CB only during forward-progress test.

							Thanx, Paul

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

 include/linux/rcutiny.h                                  |    1 
 include/linux/torture.h                                  |    2 
 kernel/rcu/rcuperf.c                                     |    1 
 kernel/rcu/rcutorture.c                                  |  188 +++++++++++++--
 kernel/rcu/update.c                                      |    1 
 kernel/torture.c                                         |    3 
 tools/testing/selftests/rcutorture/bin/kvm-test-1-run.sh |    1 
 tools/testing/selftests/rcutorture/configs/rcu/CFLIST    |    2 
 8 files changed, 172 insertions(+), 27 deletions(-)