[PATCH tip/core/rcu 0/N] v2 RCU commits for 3.4

From: Paul E. McKenney
Date: Fri Feb 03 2012 - 20:45:11 EST


Hello!

This is v2 of this patchset. Earlier versions may be found at
https://lkml.org/lkml/2012/2/1/354 and https://lkml.org/lkml/2012/2/2/575.
A big "thank you" to all the reviewers, particularly Josh Triplett, for the
excellent feedback.

This patchset makes RCU more aggressive about entering dyntick-idle mode
in order to improve energy efficiency, converts a few more call_rcu()s to
kfree_rcu(), applies a number of rcutree fixes and cleanups to rcutiny,
removes CONFIG_SMP #ifdef from treercu, allows RCU CPU stall times to
be set via sysfs, add CPU-stall capability to rcutorture, adds more
RCU-abuse diagnostics, updates documentation, and yet more fixes from
the still-ongoing top-to-bottom inspection of RCU with a special focus
on the CPU-hotplug code path. The patches are as follows:

1,26,31,33,41,40.
Documentation upgrades.
2. Improve synchronize_rcu() diagnostics, courtesy of
Frederic Weisbecker.
3. Add lockdep-RCU checks for simple self deadlock, such as calling
synchronize_rcu() while in an RCU read-side critical section.
4. Add a diagnostic for misaligned rcu_head structures. This is
preparation for a call_rcu_lazy() for added energy efficiency.
5,14,37.
Upgrades to CONFIG_RCU_FAST_NO_HZ.
6. Move CONFIG_RCU_TRACE to lib/Kconfig.debug: not for production use.
7-11. Convert several call_rcu() primitives to kfree_rcu().
12,13,15,16,35,38,39.
Fixes to and streamlining of CPU-hotplug handling based on review.
17. Remove dubious single-rcu_node optimization from rcu_start_gp().
18-22. Apply prior rcutree fixes to rcutiny.
23. Catch rcu_preempt_needs_cpu()'s name up with 2011.
24. Check for idle-loop entry while in an RCU read-side critical section.
25. Check for sleeping in TREE_RCU read-side critical sections.
27,36. Remove "#ifdef CONFIG_SMP" from treercu, move code accordingly.
28. Allow RCU CPU stall times to be adjusted at runtime via sysfs.
29. Print scheduling-clock timer information on RCU CPU stall warning
messages if requested by CONFIG_RCU_CPU_STALL_INFO config parameter.
30. Allow rcutorture to be told to hold off CPU-hotplug operations during
early boot.
32. Allow rcutorture to generate CPU stalls in order to test RCU CPU
stall warning facility.
34. Silence module-parameter warnings by converting a couple of
rcutorture's module parameters to bool.
41. Fix misplaced NULL-pointer check in rcutorture.
42. Convert WARN_ON_ONCE() in rcu_lock_acquire() to lockdep, in
part courtesy of Heiko Carstens.
43. Fix botched PTR_ERR() call, courtesy of Julia Lawall.
44. Remove now-redundant check for rcu_head misalignment.
45-47. Fix incorrect uses of RCU from the idle loop. Note that patch
47 will likely be replaced by some event-tracing upgrades from
Steven Rostedt.

For a testing-only version of this patchset from git, please see the
following subject-to-rebase branch:

git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git rcu/next

Thanx, Paul

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

Documentation/RCU/torture.txt | 20
b/Documentation/RCU/RTFP.txt | 1902 +++++++++++++++++++++++++++++++++----
b/Documentation/RCU/checklist.txt | 14
b/Documentation/RCU/stallwarn.txt | 87 +
b/Documentation/RCU/torture.txt | 13
b/Documentation/RCU/trace.txt | 36
b/arch/s390/kernel/irq.c | 9
b/drivers/cpuidle/cpuidle.c | 12
b/drivers/target/tcm_fc/tfc_sess.c | 12
b/include/linux/rcupdate.h | 2
b/include/linux/rcutiny.h | 6
b/include/linux/rcutree.h | 1
b/include/linux/sched.h | 3
b/include/linux/srcu.h | 11
b/include/trace/events/rcu.h | 63 -
b/init/Kconfig | 9
b/kernel/lockdep.c | 8
b/kernel/rcu.h | 4
b/kernel/rcupdate.c | 5
b/kernel/rcutiny.c | 4
b/kernel/rcutiny_plugin.h | 5
b/kernel/rcutorture.c | 4
b/kernel/rcutree.c | 8
b/kernel/rcutree.h | 3
b/kernel/rcutree_plugin.h | 4
b/kernel/rcutree_trace.c | 8
b/kernel/srcu.c | 6
b/lib/Kconfig.debug | 10
b/net/ipv4/cipso_ipv4.c | 11
b/net/ipv4/ip_sockglue.c | 7
b/net/mac80211/mesh_pathtbl.c | 8
include/linux/rcupdate.h | 81 +
include/linux/rcutiny.h | 4
include/linux/rcutree.h | 18
include/linux/srcu.h | 4
kernel/rcu.h | 22
kernel/rcutiny.c | 22
kernel/rcutiny_plugin.h | 72 +
kernel/rcutorture.c | 91 +
kernel/rcutree.c | 661 ++++++++----
kernel/rcutree.h | 24
kernel/rcutree_plugin.h | 443 +++++---
kernel/rcutree_trace.c | 6
kernel/srcu.c | 27
lib/Kconfig.debug | 14
45 files changed, 3055 insertions(+), 729 deletions(-)

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