Post-gp_seq torture-test updates

Hello!

This series contains torture-test updates that are sequenced after the infamous ->gp_seq conversion:

1. Remove rcutorture test version and sequence number, as these
were useful only for ABAT testing in the long-lost past.

2. Remove unused torturing_tasks() function.

3. Extract common code from rcu_torture_reader().

4. Use atomic increment for n_rcu_torture_timers.

5. Use per-CPU random state for rcu_torture_timer().

6. Make rcu_torture_timer() use rcu_torture_one_read().

7. Handle extended read-side critical sections, thus adding the
ability to test a flavor-consolidated RCU. This can be tested on rcu_sched and (to a lesser extent) rcu_bh. Gotta test the test, after all!

8. Emphasize testing of single reader protection type.

9. Disable RT throttling for boost tests, courtesy of Joel Fernandes.

10. Make boost test more robust, courtesy of Joel Fernandes.

11. Use monotonic timestamp for stall detection, courtesy of
Arnd Bergmann.

12. Add support to detect if boost kthread prio is too low, courtesy
of Joel Fernandes.

13. Fix rcu_barrier successes counter, courtesy of Joel Fernandes.

Thanx, Paul

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

 include/linux/torture.h |    2 
 kernel/rcu/rcu.h        |    6 
 kernel/rcu/rcuperf.c    |    5 
 kernel/rcu/rcutorture.c |  452 ++++++++++++++++++++++++++++++++++--------------
 kernel/rcu/tree.c       |   44 ----
 5 files changed, 339 insertions(+), 170 deletions(-)