Re: [GIT PULL rcu/next] RCU commits for 3.3

[Ingo Molnar]

* Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx> wrote:

> Hello, Ingo,
> 
> The major features of this series are RCU infrastructure in 
> support of Frederic Weisbecker's tickless userspace work and a 
> reworked RCU_FAST_NO_HZ that improves energy efficiency on 
> large lightly loaded SMP systems by allowing the 
> scheduler-clock tick to be turned off more quickly upon entry 
> to idle, even when RCU callbacks are queued on the newly idle 
> CPU.  In addition, RCU_FAST_NO_HZ may now be used on systems 
> running TREE_PREEMPT_RCU, where earlier it was restricted to 
> TREE_RCU.
> 
> In addition, this series provides additional event tracing, 
> rcutorture changes that improve automated KVM-based testing of 
> RCU, introduces an srcu_read_lock_raw() needed by uprobes, and 
> ports a couple of patches from -rt to mainline.  Finally, this 
> series updates documentation, improves diagnostics, and fixes 
> a number of bugs, including a nasty use of RCU from the idle 
> task spotted and fixed by Frederic Weisbecker.
> 
> These commits have been posted to LKML and updated based on 
> feedback:
> 
> 	https://lkml.org/lkml/2011/11/2/363
> 	https://lkml.org/lkml/2011/11/15/302
> 	https://lkml.org/lkml/2011/11/28/588
> 	https://lkml.org/lkml/2011/12/3/77
> 	https://lkml.org/lkml/2011/12/12/625
> 
> They have also been exposed to -next testing.
> 
> These changes are based off of 3.2-rc5 and are available at 
> the git repository at:
> 
> git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git rcu/next
> 
> Could you please pull them into -tip for additional testing?
> 
> 							Thanx, Paul
> 
> ------------------>
> Frederic Weisbecker (11):
>       rcu: Detect illegal rcu dereference in extended quiescent state
>       rcu: Inform the user about extended quiescent state on PROVE_RCU warning
>       rcu: Warn when rcu_read_lock() is used in extended quiescent state
>       nohz: Separate out irq exit and idle loop dyntick logic
>       nohz: Allow rcu extended quiescent state handling seperately from tick stop
>       x86: Enter rcu extended qs after idle notifier call
>       x86: Call idle notifier after irq_enter()
>       rcu: Fix early call to rcu_idle_enter()
>       nohz: Remove tick_nohz_idle_enter_norcu() / tick_nohz_idle_exit_norcu()
>       rcu: Don't check irq nesting from rcu idle entry/exit
>       rcu: Irq nesting is always 0 on rcu_enter_idle_common
> 
> Josh Triplett (1):
>       driver-core/cpu: Expose hotpluggability to the rest of the kernel
> 
> Kees Cook (1):
>       docs: Additional LWN links to RCU API
> 
> Paul E. McKenney (49):
>       rcu: ->signaled better named ->fqs_state
>       rcu: Avoid RCU-preempt expedited grace-period botch
>       rcu: Make synchronize_sched_expedited() better at work sharing
>       lockdep: Update documentation for lock-class leak detection
>       rcu: Track idleness independent of idle tasks
>       trace: Allow ftrace_dump() to be called from modules
>       rcu: Add failure tracing to rcutorture
>       rcu: Document failing tick as cause of RCU CPU stall warning
>       rcu: Disable preemption in rcu_is_cpu_idle()
>       rcu: Remove one layer of abstraction from PROVE_RCU checking
>       rcu: Warn when srcu_read_lock() is used in an extended quiescent state
>       rcu: Make srcu_read_lock_held() call common lockdep-enabled function
>       powerpc: Tell RCU about idle after hcall tracing
>       rcu: Introduce raw SRCU read-side primitives
>       rcu: Add documentation for raw SRCU read-side primitives
>       rcu: Deconfuse dynticks entry-exit tracing
>       rcu: Add more information to the wrong-idle-task complaint
>       rcu: Allow dyntick-idle mode for CPUs with callbacks
>       rcu: Fix idle-task checks
>       rcu: Permit RCU_FAST_NO_HZ to be used by TREE_PREEMPT_RCU
>       rcu: Add rcutorture system-shutdown capability
>       rcu: Control rcutorture startup from kernel boot parameters
>       sched: Add is_idle_task() to handle invalidated uses of idle_cpu()
>       rcu: Make RCU use the new is_idle_task() API
>       sparc: Make SPARC use the new is_idle_task() API
>       kdb: Make KDB use the new is_idle_task() API
>       events: Make events use the new is_idle_task() API
>       tile: Make tile use the new is_idle_task() API
>       rcu: Add rcutorture CPU-hotplug capability
>       doc: Add load/store guarantees to Documentation/atomic-ops.txt
>       rcu: Update trace_rcu_dyntick() header comment
>       rcu: Add tracing for RCU_FAST_NO_HZ
>       rcu: Go dyntick-idle more quickly if CPU has serviced current grace period
>       rcu: Avoid needlessly IPIing CPUs at GP end
>       rcu: Eliminate RCU_FAST_NO_HZ grace-period hang
>       rcu: Reduce latency of rcu_prepare_for_idle()
>       rcu: Remove dynticks false positives and RCU failures
>       rcu: Identify dyntick-idle CPUs on first force_quiescent_state() pass
>       rcu: Document same-context read-side constraints
>       rcu: Permit dyntick-idle with callbacks pending
>       rcu: Keep invoking callbacks if CPU otherwise idle
>       rcu: Adaptive dyntick-idle preparation
>       rcu: Remove redundant rcu_cpu_stall_suppress declaration
>       rcu: Make rcutorture test for hotpluggability before offlining CPUs
>       rcu: Add rcutorture tests for srcu_read_lock_raw()
>       rcu: Augment rcu_batch_end tracing for idle and callback state
>       Revert "rcu: Permit rt_mutex_unlock() with irqs disabled"
>       rcu: Apply ACCESS_ONCE() to rcu_boost() return value
>       cpu: Export cpu_up()
> 
> Thomas Gleixner (2):
>       rcu: Omit self-awaken when setting up expedited grace period
>       rcu: Remove redundant return from rcu_report_exp_rnp()
> 
>  Documentation/RCU/checklist.txt          |    6 +
>  Documentation/RCU/rcu.txt                |   10 +-
>  Documentation/RCU/stallwarn.txt          |   16 +-
>  Documentation/RCU/torture.txt            |   13 ++
>  Documentation/RCU/trace.txt              |    4 -
>  Documentation/RCU/whatisRCU.txt          |   19 ++-
>  Documentation/atomic_ops.txt             |   87 +++++++++
>  Documentation/lockdep-design.txt         |   63 +++++++
>  arch/arm/kernel/process.c                |    6 +-
>  arch/avr32/kernel/process.c              |    6 +-
>  arch/blackfin/kernel/process.c           |    6 +-
>  arch/microblaze/kernel/process.c         |    6 +-
>  arch/mips/kernel/process.c               |    6 +-
>  arch/openrisc/kernel/idle.c              |    6 +-
>  arch/powerpc/kernel/idle.c               |   15 ++-
>  arch/powerpc/platforms/iseries/setup.c   |   12 +-
>  arch/powerpc/platforms/pseries/lpar.c    |    4 +
>  arch/s390/kernel/process.c               |    6 +-
>  arch/sh/kernel/idle.c                    |    6 +-
>  arch/sparc/kernel/process_64.c           |    6 +-
>  arch/sparc/kernel/setup_32.c             |    2 +-
>  arch/tile/kernel/process.c               |    6 +-
>  arch/tile/mm/fault.c                     |    4 +-
>  arch/um/kernel/process.c                 |    6 +-
>  arch/unicore32/kernel/process.c          |    6 +-
>  arch/x86/kernel/apic/apic.c              |    6 +-
>  arch/x86/kernel/apic/io_apic.c           |    2 +-
>  arch/x86/kernel/cpu/mcheck/therm_throt.c |    2 +-
>  arch/x86/kernel/cpu/mcheck/threshold.c   |    2 +-
>  arch/x86/kernel/irq.c                    |    6 +-
>  arch/x86/kernel/process_32.c             |    6 +-
>  arch/x86/kernel/process_64.c             |   10 +-
>  drivers/base/cpu.c                       |    7 +
>  include/linux/cpu.h                      |    1 +
>  include/linux/hardirq.h                  |   21 ---
>  include/linux/rcupdate.h                 |  115 ++++++++-----
>  include/linux/sched.h                    |    8 +
>  include/linux/srcu.h                     |   87 ++++++++--
>  include/linux/tick.h                     |   11 +-
>  include/trace/events/rcu.h               |  122 +++++++++++--
>  init/Kconfig                             |   10 +-
>  kernel/cpu.c                             |    1 +
>  kernel/debug/kdb/kdb_support.c           |    2 +-
>  kernel/events/core.c                     |    2 +-
>  kernel/lockdep.c                         |   22 +++
>  kernel/rcu.h                             |    7 +
>  kernel/rcupdate.c                        |   12 ++
>  kernel/rcutiny.c                         |  149 +++++++++++++--
>  kernel/rcutiny_plugin.h                  |   29 +++-
>  kernel/rcutorture.c                      |  225 ++++++++++++++++++++++-
>  kernel/rcutree.c                         |  290 +++++++++++++++++++++---------
>  kernel/rcutree.h                         |   26 ++--
>  kernel/rcutree_plugin.h                  |  289 ++++++++++++++++++++++++------
>  kernel/rcutree_trace.c                   |   12 +-
>  kernel/rtmutex.c                         |    8 -
>  kernel/softirq.c                         |    4 +-
>  kernel/time/tick-sched.c                 |   97 ++++++----
>  kernel/trace/trace.c                     |    1 +
>  58 files changed, 1512 insertions(+), 407 deletions(-)

Pulled into tip:core/rcu, thanks a lot Paul!

Note that this commit from Frederic:

  69e1e811dcc4: sched, nohz: Track nr_busy_cpus in the sched_group_power

conflicted with this commit from Suresh in sched/core:

  69e1e811dcc4: sched, nohz: Track nr_busy_cpus in the sched_group_power

I resolved it by making the set_cpu_sd_state_idle() call 
unconditional within the newly decoupled 
tick_nohz_stop_sched_tick() function - please double check that 
it's the right resolution.

Thanks,

	Ingo
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