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: (31 commits)
  rcu: Make RCU's CPU-stall detector be default
  rcu: Add expedited grace-period support for preemptible RCU
  rcu: Enable fourth level of TREE_RCU hierarchy
  rcu: Rename "quiet" functions
  rcu: Re-arrange code to reduce #ifdef pain
  rcu: Eliminate unneeded function wrapping
  rcu: Fix grace-period-stall bug on large systems with CPU hotplug
  rcu: Eliminate __rcu_pending() false positives
  rcu: Further cleanups of use of lastcomp
  rcu: Simplify association of forced quiescent states with grace periods
  rcu: Accelerate callback processing on CPUs not detecting GP end
  rcu: Mark init-time-only rcu_bootup_announce() as __init
  rcu: Simplify association of quiescent states with grace periods
  rcu: Rename dynticks_completed to completed_fqs
  rcu: Enable synchronize_sched_expedited() fastpath
  rcu: Remove inline from forward-referenced functions
  rcu: Fix note_new_gpnum() uses of ->gpnum
  rcu: Fix synchronization for rcu_process_gp_end() uses of ->completed counter
  rcu: Prepare for synchronization fixes: clean up for non-NO_HZ handling of ->completed counter
  rcu: Cleanup: balance rcu_irq_enter()/rcu_irq_exit() calls
  ...

20 files changed, 1234 insertions, 581 deletions

diff --git a/Documentation/RCU/trace.txt b/Documentation/RCU/trace.txt
index 187bbf10c923..8608fd85e921 100644
--- a/Documentation/RCU/trace.txt
+++ b/Documentation/RCU/trace.txt
@@ -1,185 +1,10 @@
 CONFIG_RCU_TRACE debugfs Files and Formats
 
 
-The rcupreempt and rcutree implementations of RCU provide debugfs trace
-output that summarizes counters and state.  This information is useful for
-debugging RCU itself, and can sometimes also help to debug abuses of RCU.
-Note that the rcuclassic implementation of RCU does not provide debugfs
-trace output.
-
-The following sections describe the debugfs files and formats for
-preemptable RCU (rcupreempt) and hierarchical RCU (rcutree).
-
-
-Preemptable RCU debugfs Files and Formats
-
-This implementation of RCU provides three debugfs files under the
-top-level directory RCU: rcu/rcuctrs (which displays the per-CPU
-counters used by preemptable RCU) rcu/rcugp (which displays grace-period
-counters), and rcu/rcustats (which internal counters for debugging RCU).
-
-The output of "cat rcu/rcuctrs" looks as follows:
-
-CPU last cur F M
-  0    5  -5 0 0
-  1   -1   0 0 0
-  2    0   1 0 0
-  3    0   1 0 0
-  4    0   1 0 0
-  5    0   1 0 0
-  6    0   2 0 0
-  7    0  -1 0 0
-  8    0   1 0 0
-ggp = 26226, state = waitzero
-
-The per-CPU fields are as follows:
-
-o       "CPU" gives the CPU number.  Offline CPUs are not displayed.
-
-o       "last" gives the value of the counter that is being decremented
-        for the current grace period phase.  In the example above,
-        the counters sum to 4, indicating that there are still four
-        RCU read-side critical sections still running that started
-        before the last counter flip.
-
-o       "cur" gives the value of the counter that is currently being
-        both incremented (by rcu_read_lock()) and decremented (by
-        rcu_read_unlock()).  In the example above, the counters sum to
-        1, indicating that there is only one RCU read-side critical section
-        still running that started after the last counter flip.
-
-o       "F" indicates whether RCU is waiting for this CPU to acknowledge
-        a counter flip.  In the above example, RCU is not waiting on any,
-        which is consistent with the state being "waitzero" rather than
-        "waitack".
-
-o       "M" indicates whether RCU is waiting for this CPU to execute a
-        memory barrier.  In the above example, RCU is not waiting on any,
-        which is consistent with the state being "waitzero" rather than
-        "waitmb".
-
-o       "ggp" is the global grace-period counter.
-
-o       "state" is the RCU state, which can be one of the following:
-
-        o       "idle": there is no grace period in progress.
-
-        o       "waitack": RCU just incremented the global grace-period
-                counter, which has the effect of reversing the roles of
-                the "last" and "cur" counters above, and is waiting for
-                all the CPUs to acknowledge the flip.  Once the flip has
-                been acknowledged, CPUs will no longer be incrementing
-                what are now the "last" counters, so that their sum will
-                decrease monotonically down to zero.
-
-        o       "waitzero": RCU is waiting for the sum of the "last" counters
-                to decrease to zero.
-
-        o       "waitmb": RCU is waiting for each CPU to execute a memory
-                barrier, which ensures that instructions from a given CPU's
-                last RCU read-side critical section cannot be reordered
-                with instructions following the memory-barrier instruction.
-
-The output of "cat rcu/rcugp" looks as follows:
-
-oldggp=48870  newggp=48873
-
-Note that reading from this file provokes a synchronize_rcu().  The
-"oldggp" value is that of "ggp" from rcu/rcuctrs above, taken before
-executing the synchronize_rcu(), and the "newggp" value is also the
-"ggp" value, but taken after the synchronize_rcu() command returns.
-
-
-The output of "cat rcu/rcugp" looks as follows:
-
-na=1337955 nl=40 wa=1337915 wl=44 da=1337871 dl=0 dr=1337871 di=1337871
-1=50989 e1=6138 i1=49722 ie1=82 g1=49640 a1=315203 ae1=265563 a2=49640
-z1=1401244 ze1=1351605 z2=49639 m1=5661253 me1=5611614 m2=49639
-
-These are counters tracking internal preemptable-RCU events, however,
-some of them may be useful for debugging algorithms using RCU.  In
-particular, the "nl", "wl", and "dl" values track the number of RCU
-callbacks in various states.  The fields are as follows:
-
-o       "na" is the total number of RCU callbacks that have been enqueued
-        since boot.
-
-o       "nl" is the number of RCU callbacks waiting for the previous
-        grace period to end so that they can start waiting on the next
-        grace period.
-
-o       "wa" is the total number of RCU callbacks that have started waiting
-        for a grace period since boot.  "na" should be roughly equal to
-        "nl" plus "wa".
-
-o       "wl" is the number of RCU callbacks currently waiting for their
-        grace period to end.
-
-o       "da" is the total number of RCU callbacks whose grace periods
-        have completed since boot.  "wa" should be roughly equal to
-        "wl" plus "da".
-
-o       "dr" is the total number of RCU callbacks that have been removed
-        from the list of callbacks ready to invoke.  "dr" should be roughly
-        equal to "da".
-
-o       "di" is the total number of RCU callbacks that have been invoked
-        since boot.  "di" should be roughly equal to "da", though some
-        early versions of preemptable RCU had a bug so that only the
-        last CPU's count of invocations was displayed, rather than the
-        sum of all CPU's counts.
-
-o       "1" is the number of calls to rcu_try_flip().  This should be
-        roughly equal to the sum of "e1", "i1", "a1", "z1", and "m1"
-        described below.  In other words, the number of times that
-        the state machine is visited should be equal to the sum of the
-        number of times that each state is visited plus the number of
-        times that the state-machine lock acquisition failed.
-
-o       "e1" is the number of times that rcu_try_flip() was unable to
-        acquire the fliplock.
-
-o       "i1" is the number of calls to rcu_try_flip_idle().
-
-o       "ie1" is the number of times rcu_try_flip_idle() exited early
-        due to the calling CPU having no work for RCU.
-
-o       "g1" is the number of times that rcu_try_flip_idle() decided
-        to start a new grace period.  "i1" should be roughly equal to
+The rcutree implementation of RCU provides debugfs trace output that
+summarizes counters and state.  This information is useful for debugging
+RCU itself, and can sometimes also help to debug abuses of RCU.
+The following sections describe the debugfs files and formats.