Merge branch 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  rcu: remove unused __list_for_each_rcu() macro
  rculist: fix borked __list_for_each_rcu() macro
  rcu: reduce __call_rcu()-induced contention on rcu_node structures
  rcu: limit rcu_node leaf-level fanout
  rcu: fine-tune grace-period begin/end checks
  rcu: Keep gpnum and completed fields synchronized
  rcu: Stop chasing QS if another CPU did it for us
  rcu: increase synchronize_sched_expedited() batching
  rcu: Make synchronize_srcu_expedited() fast if running readers
  rcu: fix race condition in synchronize_sched_expedited()
  rcu: update documentation/comments for Lai's adoption patch
  rcu,cleanup: simplify the code when cpu is dying
  rcu,cleanup: move synchronize_sched_expedited() out of sched.c
  rcu: get rid of obsolete "classic" names in TREE_RCU tracing
  rcu: Distinguish between boosting and boosted
  rcu: document TINY_RCU and TINY_PREEMPT_RCU tracing.
  rcu: add tracing for TINY_RCU and TINY_PREEMPT_RCU
  rcu: priority boosting for TINY_PREEMPT_RCU
  rcu: move TINY_RCU from softirq to kthread
  rcu: add priority-inversion testing to rcutorture

1 files changed, 54 insertions, 1 deletions

diff --git a/init/Kconfig b/init/Kconfig
index c9728992a776..526ec1c7456a 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -393,7 +393,6 @@ config PREEMPT_RCU
 
 config RCU_TRACE
         bool "Enable tracing for RCU"
-        depends on TREE_RCU || TREE_PREEMPT_RCU
         help
           This option provides tracing in RCU which presents stats
           in debugfs for debugging RCU implementation.
@@ -459,6 +458,60 @@ config TREE_RCU_TRACE
           TREE_PREEMPT_RCU implementations, permitting Makefile to
           trivially select kernel/rcutree_trace.c.
 
+config RCU_BOOST
+        bool "Enable RCU priority boosting"
+        depends on RT_MUTEXES && TINY_PREEMPT_RCU
+        default n
+        help
+          This option boosts the priority of preempted RCU readers that
+          block the current preemptible RCU grace period for too long.
+          This option also prevents heavy loads from blocking RCU
+          callback invocation for all flavors of RCU.
+
+          Say Y here if you are working with real-time apps or heavy loads
+          Say N here if you are unsure.
+
+config RCU_BOOST_PRIO
+        int "Real-time priority to boost RCU readers to"
+        range 1 99
+        depends on RCU_BOOST
+        default 1
+        help
+          This option specifies the real-time priority to which preempted
+          RCU readers are to be boosted.  If you are working with CPU-bound
+          real-time applications, you should specify a priority higher then
+          the highest-priority CPU-bound application.
+
+          Specify the real-time priority, or take the default if unsure.
+
+config RCU_BOOST_DELAY
+        int "Milliseconds to delay boosting after RCU grace-period start"
+        range 0 3000
+        depends on RCU_BOOST
+        default 500
+        help
+          This option specifies the time to wait after the beginning of
+          a given grace period before priority-boosting preempted RCU
+          readers blocking that grace period.  Note that any RCU reader
+          blocking an expedited RCU grace period is boosted immediately.
+
+          Accept the default if unsure.
+
+config SRCU_SYNCHRONIZE_DELAY
+        int "Microseconds to delay before waiting for readers"
+        range 0 20
+        default 10
+        help
+          This option controls how long SRCU delays before entering its
+          loop waiting on SRCU readers.  The purpose of this loop is
+          to avoid the unconditional context-switch penalty that would
+          otherwise be incurred if there was an active SRCU reader,
+          in a manner similar to adaptive locking schemes.  This should
+          be set to be a bit longer than the common-case SRCU read-side
+          critical-section overhead.
+
+          Accept the default if unsure.
+
 endmenu # "RCU Subsystem"
 
 config IKCONFIG