[RFC GIT PULL rcu/next] v2 RCU commits for 3.7

From: Paul E. McKenney
Date: Wed Sep 26 2012 - 00:45:44 EST


Hello, Ingo,

This is now an RFC pull for only one of the previous two reasons.
The commits have how been through -next without the adaptive-idle patches,
but although good progress has been made on the adaptive-idle patches,
they are still not quite there yet. Again, the current adaptive-idle
series has been rebased as rcu/idle on top of rcu/next, the latter branch
being the subject of this pull request. Also, I have merged the
conflicting -tip branches into rcu/next, resolving the conflicts.
(One set was adjacent insertions/deletions, the other was resolved
as Peter Zijlstra described at https://lkml.org/lkml/2012/9/5/585.

Again, the major features of this series are:

0. A fix for a latent bug that has been in RCU ever since the
addition of CPU stall warnings. This bug results in
false-positive stall warnings, but thus far only on embedded
systems with severely cut-down userspace configurations.
This fix is located on an rcu/urgent branch, with the rest
of the commits based on top of it. This commit CCs stable.
Given that the merge window is coming quite soon and given
the small number of affected users, I do -not- recommend
pushing it to 3.6, but the separate branch makes it easy to
find if someone needs it.

1. Further reductions in latency spikes for huge systems, along
with additional boot-time adaptation to the actual hardware.
This is a large change, as it moves RCU grace-period
initialization and cleanup, along with quiescent-state forcing,
from softirq to a kthread. However, it appears to be in
quite good shape (famous last words). Posted to LKML at
https://lkml.org/lkml/2012/9/20/427.

2. Updates to documentation and rcutorture, the latter category
including keeping statistics on CPU-hotplug latencies and
fixing some initialization-time races. Posted to LKML at
https://lkml.org/lkml/2012/8/30/193.

3. Miscellaneous fixes and improvements, posted to LKML at
https://lkml.org/lkml/2012/8/30/199.

4. CPU-hotplug fixes and improvements, posted to LKML at
https://lkml.org/lkml/2012/8/30/292 for first three and at
https://lkml.org/lkml/2012/8/3/416.

5. Idle-loop fixes that were omitted on an earlier submission,
posted to LKML at https://lkml.org/lkml/2012/8/30/251.

As noted earlier, all of these commits have been exposed to -next testing,
albeit in combination with adaptive-idle commits that will hopefully be
following soon.

These changes are available in the git repository at:

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

Thanx, Paul

-------------------->
Dimitri Sivanich (1):
rcu: Segregate rcu_state fields to improve cache locality

Frederic Weisbecker (11):
alpha: Fix preemption handling in idle loop
alpha: Add missing RCU idle APIs on idle loop
cris: Add missing RCU idle APIs on idle loop
frv: Add missing RCU idle APIs on idle loop
h8300: Add missing RCU idle APIs on idle loop
m32r: Add missing RCU idle APIs on idle loop
m68k: Add missing RCU idle APIs on idle loop
mn10300: Add missing RCU idle APIs on idle loop
parisc: Add missing RCU idle APIs on idle loop
score: Add missing RCU idle APIs on idle loop
xtensa: Add missing RCU idle APIs on idle loop

Li Zhong (1):
rcu: Move TINY_RCU quiescent state out of extended quiescent state

Michael Wang (1):
kmemleak: Replace list_for_each_continue_rcu with new interface

Paul E. McKenney (46):
rcu: Move RCU grace-period initialization into a kthread
rcu: Prevent initialization-time quiescent-state race
rcu: Allow RCU grace-period initialization to be preempted
rcu: Move RCU grace-period cleanup into kthread
rcu: Allow RCU grace-period cleanup to be preempted
rcu: Break up rcu_gp_kthread() into subfunctions
rcu: Prevent offline CPUs from executing RCU core code
rcu: Provide OOM handler to motivate lazy RCU callbacks
rcu: Move quiescent-state forcing into kthread
rcu: Allow RCU quiescent-state forcing to be preempted
rcu: Adjust debugfs tracing for kthread-based quiescent-state forcing
rcu: Prevent force_quiescent_state() memory contention
rcu: Control grace-period duration from sysfs
rcu: Make rcutree module parameters visible in sysfs
rcu: Fix day-zero grace-period initialization/cleanup race
rcu: Add random PROVE_RCU_DELAY to grace-period initialization
rcu: Adjust for unconditional ->completed assignment
rcu: Eliminate signed overflow in synchronize_rcu_expedited()
rcu: Reduce synchronize_rcu_expedited() latency
rcu: Simplify quiescent-state detection
rcu: Handle unbalanced rcu_node configurations with few CPUs
rcu: Shrink RCU based on number of CPUs
rcu: Update rcutorture defaults
rcu: Track CPU-hotplug duration statistics
rcu: Document SRCU dead-CPU capabilities, emphasize read-side limits
rcu: Switch rcutorture to pr_alert() and friends
rcu: Prevent initialization race in rcutorture kthreads
rcu: Add PROVE_RCU_DELAY to provoke difficult races
rcu: Pull TINY_RCU dyntick-idle tracing into non-idle region
rcu: Properly initialize ->boost_tasks on CPU offline
rcu: Permit RCU_NONIDLE() to be used from interrupt context
rcu: Improve boost selection when moving tasks to root rcu_node
rcu: Make offline-CPU checking allow for indefinite delays
rcu: Fix obsolete rcu_initiate_boost() header comment
rcu: Apply for_each_rcu_flavor() to increment_cpu_stall_ticks()
rcu: Avoid rcu_print_detail_task_stall_rnp() segfault
rcu: Protect rcu_node accesses during CPU stall warnings
rcu: Avoid spurious RCU CPU stall warnings
rcu: Remove redundant memory barrier from __call_rcu()
rcu: Move TINY_PREEMPT_RCU away from raw_local_irq_save()
time: RCU permitted to stop idle entry via softirq
rcu: Fix CONFIG_RCU_FAST_NO_HZ stall warning message
rcu: Remove _rcu_barrier() dependency on __stop_machine()
rcu: Disallow callback registry on offline CPUs
ia64: Add missing RCU idle APIs on idle loop
Merge branches 'bigrt.2012.09.23a', 'doctorture.2012.09.23a', 'fixes.2012.09.23a', 'hotplug.2012.09.23a' and 'idlechop.2012.09.23a' into HEAD

Peter Zijlstra (1):
sched: Fix load avg vs cpu-hotplug

Silas Boyd-Wickizer (2):
Use get_online_cpus to avoid races involving CPU hotplug
Use get_online_cpus to avoid races involving CPU hotplug

Documentation/RCU/checklist.txt | 6 +
Documentation/RCU/stallwarn.txt | 16 +-
Documentation/RCU/trace.txt | 43 +--
Documentation/RCU/whatisRCU.txt | 9 +-
Documentation/kernel-parameters.txt | 11 +
arch/alpha/kernel/process.c | 6 +-
arch/alpha/kernel/smp.c | 1 +
arch/cris/kernel/process.c | 3 +
arch/frv/kernel/process.c | 3 +
arch/h8300/kernel/process.c | 3 +
arch/ia64/kernel/process.c | 3 +
arch/m32r/kernel/process.c | 3 +
arch/m68k/kernel/process.c | 3 +
arch/mn10300/kernel/process.c | 3 +
arch/parisc/kernel/process.c | 3 +
arch/score/kernel/process.c | 4 +-
arch/x86/kernel/cpuid.c | 5 +
arch/x86/kernel/msr.c | 5 +
arch/xtensa/kernel/process.c | 3 +
include/linux/interrupt.h | 2 +
include/linux/rcupdate.h | 6 +-
kernel/rcupdate.c | 4 +
kernel/rcutiny.c | 33 +-
kernel/rcutiny_plugin.h | 10 +-
kernel/rcutorture.c | 159 +++++----
kernel/rcutree.c | 690 ++++++++++++++++++-----------------
kernel/rcutree.h | 31 +-
kernel/rcutree_plugin.h | 174 +++++++--
kernel/rcutree_trace.c | 19 +-
kernel/sched/core.c | 41 +-
kernel/time/tick-sched.c | 3 +-
lib/Kconfig.debug | 14 +
mm/kmemleak.c | 6 +-
33 files changed, 771 insertions(+), 554 deletions(-)

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