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

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

[Ingo Molnar]

* Paul E. McKenney <paulmck@linux.vnet.ibm.com> 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

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

[Frederic Weisbecker]

On Wed, Dec 14, 2011 at 04:47:36PM +0100, Ingo Molnar wrote:
> 
> * Paul E. McKenney <paulmck@linux.vnet.ibm.com> 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.

After a quick look, I believe this should rather be under tick_nohz_idle_enter(),
(This is the equivalent of the old tick_nohz_stop_sched_tick(1))
This wants to be set only once we enter idle, not everytime we have an idle
interrupt.

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

[Frederic Weisbecker]

On Wed, Dec 14, 2011 at 05:30:11PM +0100, Frederic Weisbecker wrote:
> On Wed, Dec 14, 2011 at 04:47:36PM +0100, Ingo Molnar wrote:
> > 
> > * Paul E. McKenney <paulmck@linux.vnet.ibm.com> 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.
> 
> After a quick look, I believe this should rather be under tick_nohz_idle_enter(),
> (This is the equivalent of the old tick_nohz_stop_sched_tick(1))
> This wants to be set only once we enter idle, not everytime we have an idle
> interrupt.

I don't know how you plan to fix the conflict, by redoing the merge or by
applying a patch on tip/master.

In any case, here is a patch you can use. Feel free to apply it as is
or to just refer to its diff to redo the merge:

(Outrageously only compile tested)

---
From: Frederic Weisbecker <fweisbec@gmail.com>
Date: Wed, 14 Dec 2011 18:36:00 +0100
Subject: [PATCH] sched: Only update the CPU idleness in the domain
 hierarchy from idle loop entry

We don't need to inform the sched domain hierarchy about the
CPU idleness everytime we call tick_nohz_stop_sched_tick() as this
includes both idle loop entry and idle interrupt exit.

Doing it once from the idle loop entry is enough, call
set_cpu_sd_state_idle() only from tick_nohz_idle_enter() instead
to fix this.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
---
 kernel/time/tick-sched.c |   16 ++++++++--------
 1 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index 1f6dc515..696c997 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -289,14 +289,6 @@ static void tick_nohz_stop_sched_tick(struct tick_sched *ts)
 	now = tick_nohz_start_idle(cpu, ts);
 
 	/*
-	 * Update the idle state in the scheduler domain hierarchy
-	 * when tick_nohz_stop_sched_tick() is called from the idle loop.
-	 * State will be updated to busy during the first busy tick after
-	 * exiting idle.
-	 */
-	set_cpu_sd_state_idle();
-
-	/*
 	 * If this cpu is offline and it is the one which updates
 	 * jiffies, then give up the assignment and let it be taken by
 	 * the cpu which runs the tick timer next. If we don't drop
@@ -483,6 +475,14 @@ void tick_nohz_idle_enter(void)
 	 * update of the idle time accounting in tick_nohz_start_idle().
 	 */
 	ts->inidle = 1;
+
+	/*
+	 * Update the idle state in the scheduler domain hierarchy
+	 * when tick_nohz_idle_enter() is called from the idle loop.
+	 * State will be updated to busy during the first busy tick after
+	 * exiting idle.
+	 */
+	set_cpu_sd_state_idle();
 	tick_nohz_stop_sched_tick(ts);
 
 	local_irq_enable();
-- 
1.7.5.4

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

[Paul E. McKenney]

On Wed, Dec 14, 2011 at 06:47:38PM +0100, Frederic Weisbecker wrote:
> On Wed, Dec 14, 2011 at 05:30:11PM +0100, Frederic Weisbecker wrote:
> > On Wed, Dec 14, 2011 at 04:47:36PM +0100, Ingo Molnar wrote:
> > > * Paul E. McKenney <paulmck@linux.vnet.ibm.com> wrote:

[ . . . ]

> > > 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.
> > 
> > After a quick look, I believe this should rather be under tick_nohz_idle_enter(),
> > (This is the equivalent of the old tick_nohz_stop_sched_tick(1))
> > This wants to be set only once we enter idle, not everytime we have an idle
> > interrupt.
> 
> I don't know how you plan to fix the conflict, by redoing the merge or by
> applying a patch on tip/master.
> 
> In any case, here is a patch you can use. Feel free to apply it as is
> or to just refer to its diff to redo the merge:
> 
> (Outrageously only compile tested)

I have started up a short rcutorture test of this patch on top of
tip/master, will let you know how it goes.

							Thanx, Paul

> ---
> From: Frederic Weisbecker <fweisbec@gmail.com>
> Date: Wed, 14 Dec 2011 18:36:00 +0100
> Subject: [PATCH] sched: Only update the CPU idleness in the domain
>  hierarchy from idle loop entry
> 
> We don't need to inform the sched domain hierarchy about the
> CPU idleness everytime we call tick_nohz_stop_sched_tick() as this
> includes both idle loop entry and idle interrupt exit.
> 
> Doing it once from the idle loop entry is enough, call
> set_cpu_sd_state_idle() only from tick_nohz_idle_enter() instead
> to fix this.
> 
> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
> Cc: Suresh Siddha <suresh.b.siddha@intel.com>
> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
> ---
>  kernel/time/tick-sched.c |   16 ++++++++--------
>  1 files changed, 8 insertions(+), 8 deletions(-)
> 
> diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
> index 1f6dc515..696c997 100644
> --- a/kernel/time/tick-sched.c
> +++ b/kernel/time/tick-sched.c
> @@ -289,14 +289,6 @@ static void tick_nohz_stop_sched_tick(struct tick_sched *ts)
>  	now = tick_nohz_start_idle(cpu, ts);
> 
>  	/*
> -	 * Update the idle state in the scheduler domain hierarchy
> -	 * when tick_nohz_stop_sched_tick() is called from the idle loop.
> -	 * State will be updated to busy during the first busy tick after
> -	 * exiting idle.
> -	 */
> -	set_cpu_sd_state_idle();
> -
> -	/*
>  	 * If this cpu is offline and it is the one which updates
>  	 * jiffies, then give up the assignment and let it be taken by
>  	 * the cpu which runs the tick timer next. If we don't drop
> @@ -483,6 +475,14 @@ void tick_nohz_idle_enter(void)
>  	 * update of the idle time accounting in tick_nohz_start_idle().
>  	 */
>  	ts->inidle = 1;
> +
> +	/*
> +	 * Update the idle state in the scheduler domain hierarchy
> +	 * when tick_nohz_idle_enter() is called from the idle loop.
> +	 * State will be updated to busy during the first busy tick after
> +	 * exiting idle.
> +	 */
> +	set_cpu_sd_state_idle();
>  	tick_nohz_stop_sched_tick(ts);
> 
>  	local_irq_enable();
> -- 
> 1.7.5.4
> 
> 

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

[Suresh Siddha]

On Wed, 2011-12-14 at 09:47 -0800, Frederic Weisbecker wrote:
> I don't know how you plan to fix the conflict, by redoing the merge or by
> applying a patch on tip/master.
> 
> In any case, here is a patch you can use. Feel free to apply it as is
> or to just refer to its diff to redo the merge:
> 
> (Outrageously only compile tested)
> 
> ---
> From: Frederic Weisbecker <fweisbec@gmail.com>
> Date: Wed, 14 Dec 2011 18:36:00 +0100
> Subject: [PATCH] sched: Only update the CPU idleness in the domain
>  hierarchy from idle loop entry
> 
> We don't need to inform the sched domain hierarchy about the
> CPU idleness everytime we call tick_nohz_stop_sched_tick() as this
> includes both idle loop entry and idle interrupt exit.
> 
> Doing it once from the idle loop entry is enough, call
> set_cpu_sd_state_idle() only from tick_nohz_idle_enter() instead
> to fix this.
> 
> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
> Cc: Suresh Siddha <suresh.b.siddha@intel.com>
> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>

Acked-by: Suresh Siddha <suresh.b.siddha@intel.com>

> ---
>  kernel/time/tick-sched.c |   16 ++++++++--------
>  1 files changed, 8 insertions(+), 8 deletions(-)
> 
> diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
> index 1f6dc515..696c997 100644
> --- a/kernel/time/tick-sched.c
> +++ b/kernel/time/tick-sched.c
> @@ -289,14 +289,6 @@ static void tick_nohz_stop_sched_tick(struct tick_sched *ts)
>         now = tick_nohz_start_idle(cpu, ts);
> 
>         /*
> -        * Update the idle state in the scheduler domain hierarchy
> -        * when tick_nohz_stop_sched_tick() is called from the idle loop.
> -        * State will be updated to busy during the first busy tick after
> -        * exiting idle.
> -        */
> -       set_cpu_sd_state_idle();
> -
> -       /*
>          * If this cpu is offline and it is the one which updates
>          * jiffies, then give up the assignment and let it be taken by
>          * the cpu which runs the tick timer next. If we don't drop
> @@ -483,6 +475,14 @@ void tick_nohz_idle_enter(void)
>          * update of the idle time accounting in tick_nohz_start_idle().
>          */
>         ts->inidle = 1;
> +
> +       /*
> +        * Update the idle state in the scheduler domain hierarchy
> +        * when tick_nohz_idle_enter() is called from the idle loop.
> +        * State will be updated to busy during the first busy tick after
> +        * exiting idle.
> +        */
> +       set_cpu_sd_state_idle();
>         tick_nohz_stop_sched_tick(ts);
> 
>         local_irq_enable();
> --
> 1.7.5.4
> 
> 

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

[Paul E. McKenney]

On Wed, Dec 14, 2011 at 05:35:22PM -0800, Suresh Siddha wrote:
> On Wed, 2011-12-14 at 09:47 -0800, Frederic Weisbecker wrote:
> > I don't know how you plan to fix the conflict, by redoing the merge or by
> > applying a patch on tip/master.
> > 
> > In any case, here is a patch you can use. Feel free to apply it as is
> > or to just refer to its diff to redo the merge:
> > 
> > (Outrageously only compile tested)
> > 
> > ---
> > From: Frederic Weisbecker <fweisbec@gmail.com>
> > Date: Wed, 14 Dec 2011 18:36:00 +0100
> > Subject: [PATCH] sched: Only update the CPU idleness in the domain
> >  hierarchy from idle loop entry
> > 
> > We don't need to inform the sched domain hierarchy about the
> > CPU idleness everytime we call tick_nohz_stop_sched_tick() as this
> > includes both idle loop entry and idle interrupt exit.
> > 
> > Doing it once from the idle loop entry is enough, call
> > set_cpu_sd_state_idle() only from tick_nohz_idle_enter() instead
> > to fix this.
> > 
> > Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
> > Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
> > Cc: Suresh Siddha <suresh.b.siddha@intel.com>
> > Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
> 
> Acked-by: Suresh Siddha <suresh.b.siddha@intel.com>

Tested-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

> > ---
> >  kernel/time/tick-sched.c |   16 ++++++++--------
> >  1 files changed, 8 insertions(+), 8 deletions(-)
> > 
> > diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
> > index 1f6dc515..696c997 100644
> > --- a/kernel/time/tick-sched.c
> > +++ b/kernel/time/tick-sched.c
> > @@ -289,14 +289,6 @@ static void tick_nohz_stop_sched_tick(struct tick_sched *ts)
> >         now = tick_nohz_start_idle(cpu, ts);
> > 
> >         /*
> > -        * Update the idle state in the scheduler domain hierarchy
> > -        * when tick_nohz_stop_sched_tick() is called from the idle loop.
> > -        * State will be updated to busy during the first busy tick after
> > -        * exiting idle.
> > -        */
> > -       set_cpu_sd_state_idle();
> > -
> > -       /*
> >          * If this cpu is offline and it is the one which updates
> >          * jiffies, then give up the assignment and let it be taken by
> >          * the cpu which runs the tick timer next. If we don't drop
> > @@ -483,6 +475,14 @@ void tick_nohz_idle_enter(void)
> >          * update of the idle time accounting in tick_nohz_start_idle().
> >          */
> >         ts->inidle = 1;
> > +
> > +       /*
> > +        * Update the idle state in the scheduler domain hierarchy
> > +        * when tick_nohz_idle_enter() is called from the idle loop.
> > +        * State will be updated to busy during the first busy tick after
> > +        * exiting idle.
> > +        */
> > +       set_cpu_sd_state_idle();
> >         tick_nohz_stop_sched_tick(ts);
> > 
> >         local_irq_enable();
> > --
> > 1.7.5.4
> > 
> > 
> 
> 

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

[Ingo Molnar]

* Frederic Weisbecker <fweisbec@gmail.com> wrote:

> I don't know how you plan to fix the conflict, by redoing the 
> merge or by applying a patch on tip/master.

I've re-done the merge - thanks guys!

	Ingo