Merge branch 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull RCU changes from Ingo Molnar:
 "SRCU changes:

   - These include debugging aids, updates that move towards the goal of
     permitting srcu_read_lock() and srcu_read_unlock() to be used from
     idle and offline CPUs, and a few small fixes.

  Changes to rcutorture and to RCU documentation:

   - Posted to LKML at https://lkml.org/lkml/2013/1/26/188

  Enhancements to uniprocessor handling in tiny RCU:

   - Posted to LKML at https://lkml.org/lkml/2013/1/27/2

  Tag RCU callbacks with grace-period number to simplify callback
  advancement:

   - Posted to LKML at https://lkml.org/lkml/2013/1/26/203

  Miscellaneous fixes:

   - Posted to LKML at https://lkml.org/lkml/2013/1/26/204"

* 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (27 commits)
  srcu: use ACCESS_ONCE() to access sp->completed in srcu_read_lock()
  srcu: Update synchronize_srcu_expedited()'s comments
  srcu: Update synchronize_srcu()'s comments
  srcu: Remove checks preventing idle CPUs from calling srcu_read_lock()
  srcu: Remove checks preventing offline CPUs from calling srcu_read_lock()
  srcu: Simple cleanup for cleanup_srcu_struct()
  srcu: Add might_sleep() annotation to synchronize_srcu()
  srcu: Simplify __srcu_read_unlock() via this_cpu_dec()
  rcu: Allow rcutorture to be built at low optimization levels
  rcu: Make rcutorture's shuffler task shuffle recently added tasks
  rcu: Allow TREE_PREEMPT_RCU on UP systems
  rcu: Provide RCU CPU stall warnings for tiny RCU
  context_tracking: Add comments on interface and internals
  rcu: Remove obsolete Kconfig option from comment
  rcu: Remove unused code originally used for context tracking
  rcu: Consolidate debugging Kconfig options
  rcu: Correct 'optimized' to 'optimize' in header comment
  rcu: Trace callback acceleration
  rcu: Tag callback lists with corresponding grace-period number
  rcutorture: Don't compare ptr with 0
  ...

1 files changed, 61 insertions, 56 deletions

diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 67604e599384..a1714c897e3f 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -605,61 +605,6 @@ config PROVE_LOCKING
 
          For more details, see Documentation/lockdep-design.txt.
 
-config PROVE_RCU
-        bool "RCU debugging: prove RCU correctness"
-        depends on PROVE_LOCKING
-        default n
-        help
-         This feature enables lockdep extensions that check for correct
-         use of RCU APIs.  This is currently under development.  Say Y
-         if you want to debug RCU usage or help work on the PROVE_RCU
-         feature.
-
-         Say N if you are unsure.
-
-config PROVE_RCU_REPEATEDLY
-        bool "RCU debugging: don't disable PROVE_RCU on first splat"
-        depends on PROVE_RCU
-        default n
-        help
-         By itself, PROVE_RCU will disable checking upon issuing the
-         first warning (or "splat").  This feature prevents such
-         disabling, allowing multiple RCU-lockdep warnings to be printed
-         on a single reboot.
-
-         Say Y to allow multiple RCU-lockdep warnings per boot.
-
-         Say N if you are unsure.
-
-config PROVE_RCU_DELAY
-        bool "RCU debugging: preemptible RCU race provocation"
-        depends on DEBUG_KERNEL && PREEMPT_RCU
-        default n
-        help
-         There is a class of races that involve an unlikely preemption
-         of __rcu_read_unlock() just after ->rcu_read_lock_nesting has
-         been set to INT_MIN.  This feature inserts a delay at that
-         point to increase the probability of these races.
-
-         Say Y to increase probability of preemption of __rcu_read_unlock().
-
-         Say N if you are unsure.
-
-config SPARSE_RCU_POINTER
-        bool "RCU debugging: sparse-based checks for pointer usage"
-        default n
-        help
-         This feature enables the __rcu sparse annotation for
-         RCU-protected pointers.  This annotation will cause sparse
-         to flag any non-RCU used of annotated pointers.  This can be
-         helpful when debugging RCU usage.  Please note that this feature
-         is not intended to enforce code cleanliness; it is instead merely
-         a debugging aid.
-
-         Say Y to make sparse flag questionable use of RCU-protected pointers
-
-         Say N if you are unsure.
-
 config LOCKDEP
         bool
         depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
@@ -937,6 +882,63 @@ config BOOT_PRINTK_DELAY
           BOOT_PRINTK_DELAY also may cause LOCKUP_DETECTOR to detect
           what it believes to be lockup conditions.
 
+menu "RCU Debugging"
+
+config PROVE_RCU
+        bool "RCU debugging: prove RCU correctness"
+        depends on PROVE_LOCKING
+        default n
+        help
+         This feature enables lockdep extensions that check for correct
+         use of RCU APIs.  This is currently under development.  Say Y
+         if you want to debug RCU usage or help work on the PROVE_RCU
+         feature.
+
+         Say N if you are unsure.
+
+config PROVE_RCU_REPEATEDLY
+        bool "RCU debugging: don't disable PROVE_RCU on first splat"
+        depends on PROVE_RCU
+        default n
+        help
+         By itself, PROVE_RCU will disable checking upon issuing the
+         first warning (or "splat").  This feature prevents such
+         disabling, allowing multiple RCU-lockdep warnings to be printed
+         on a single reboot.
+
+         Say Y to allow multiple RCU-lockdep warnings per boot.
+
+         Say N if you are unsure.
+
+config PROVE_RCU_DELAY
+        bool "RCU debugging: preemptible RCU race provocation"
+        depends on DEBUG_KERNEL && PREEMPT_RCU
+        default n
+        help
+         There is a class of races that involve an unlikely preemption
+         of __rcu_read_unlock() just after ->rcu_read_lock_nesting has
+         been set to INT_MIN.  This feature inserts a delay at that
+         point to increase the probability of these races.
+
+         Say Y to increase probability of preemption of __rcu_read_unlock().
+
+         Say N if you are unsure.
+
+config SPARSE_RCU_POINTER
+        bool "RCU debugging: sparse-based checks for pointer usage"
+        default n
+        help
+         This feature enables the __rcu sparse annotation for
+         RCU-protected pointers.  This annotation will cause sparse
+         to flag any non-RCU used of annotated pointers.  This can be
+         helpful when debugging RCU usage.  Please note that this feature
+         is not intended to enforce code cleanliness; it is instead merely
+         a debugging aid.
+
+         Say Y to make sparse flag questionable use of RCU-protected pointers
+
+         Say N if you are unsure.
+
 config RCU_TORTURE_TEST
         tristate "torture tests for RCU"
         depends on DEBUG_KERNEL
@@ -970,7 +972,7 @@ config RCU_TORTURE_TEST_RUNNABLE
 
 config RCU_CPU_STALL_TIMEOUT
         int "RCU CPU stall timeout in seconds"
-        depends on TREE_RCU || TREE_PREEMPT_RCU
+        depends on RCU_STALL_COMMON
         range 3 300
         default 21
         help
@@ -1008,6 +1010,7 @@ config RCU_CPU_STALL_INFO
 config RCU_TRACE
         bool "Enable tracing for RCU"
         depends on DEBUG_KERNEL
+        select TRACE_CLOCK
         help
           This option provides tracing in RCU which presents stats
           in debugfs for debugging RCU implementation.
@@ -1015,6 +1018,8 @@ config RCU_TRACE
           Say Y here if you want to enable RCU tracing
           Say N if you are unsure.
 
+endmenu # "RCU Debugging"
+
 config KPROBES_SANITY_TEST
         bool "Kprobes sanity tests"
         depends on DEBUG_KERNEL