rcu: v2 patches queued for 2.6.35

Hello!

RFC preview of RCU patches queued for 2.6.35, take 2. Take 1 is at
http://lkml.org/lkml/2010/4/5/134. Changes to old patches noted in "[]", new patches flagged with "New".

1. substitute set_need_resched for sending resched IPIs
This reduces OS jitter.

2. make dead code really dead. [Updated commit message as suggested
by Mathieu Desnoyers.]
3. move some code from macro to function
Cleanups from Lai Jiangshan.

4. ignore offline CPUs in last non dyntick idle CPU check
Fix to my CONFIG_RCU_FAST_NO_HZ code to handle offline and non-existent CPUs, also from Lai Jiangshan.

5. fix bogus CONFIG_PROVE_LOCKING in comments to reality
6. fix now bogus rcu_scheduler_active comments
Comment fixups.

7. shrink rcutiny by making synchronize_rcu_bh be inline
Shrink TINY_RCU some more.

8. rename rcutiny rcu_ctrlblk to rcu_sched_ctrlblk
First step towards TINY_PREEMPTIBLE_RCU.

9. refactor RCU's context switch handling
Reduce the number of needless softirqs.

10. slim down rcutiny by removing rcu_scheduler_active and friends
More shrinkage for TINY_RCU

11. New: enable CPU_STALL_VERBOSE by default. It will have been in one
release, so time to enable it.

12. New: disable CPU stall warnings upon panic

13. New: print boot-time console messages if RCU configs out of ordinary

14. New: improve RCU CPU stall-warning messages

15. New: permit discontiguous cpu_possible_mask CPU numbering

16. New: v2: reduce the number of spurious RCU_SOFTIRQ invocations

Thanx, Paul

 b/Documentation/RCU/trace.txt |   35 ++++++------
 b/include/linux/rcupdate.h    |   15 ++---
 b/include/linux/rcutiny.h     |   12 +++-
 b/include/linux/rcutree.h     |    2 
 b/include/linux/srcu.h        |    4 -
 b/kernel/rcupdate.c           |   19 ------
 b/kernel/rcutiny.c            |    9 ---
 b/kernel/rcutiny_plugin.h     |   39 +++++++++++++
 b/kernel/rcutree.c            |   10 +++
 b/kernel/rcutree.h            |    1 
 b/kernel/rcutree_plugin.h     |    2 
 b/kernel/rcutree_trace.c      |    4 +
 b/kernel/sched.c              |    2 
 b/kernel/softirq.c            |    2 
 b/lib/Kconfig.debug           |    2 
 include/linux/rcupdate.h      |   12 +---
 include/linux/rcutiny.h       |   17 +++++
 include/linux/rcutree.h       |    4 +
 kernel/rcutiny.c              |   20 ++++--
 kernel/rcutree.c              |  121 +++++++++++++++++++++++++++++-------------
 kernel/rcutree.h              |    1 
 kernel/rcutree_plugin.h       |   55 +++++++++++++++++--
 22 files changed, 275 insertions(+), 113 deletions(-)