rcu: Remove TINY_PREEMPT_RCU tracing documentation

Because TINY_PREEMPT_RCU is no more, this commit removes its tracing
formats from the documentation.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>

diff --git a/Documentation/RCU/trace.txt b/Documentation/RCU/trace.txt
index c776968..f3778f8 100644 (file)
--- a/Documentation/RCU/trace.txt
+++ b/Documentation/RCU/trace.txt
@@ -530,113 +530,21 @@ o        "nos" counts the number of times we balked for other
        reasons, e.g., the grace period ended first.
 
 
-CONFIG_TINY_RCU and CONFIG_TINY_PREEMPT_RCU debugfs Files and Formats
+CONFIG_TINY_RCU debugfs Files and Formats
 
 These implementations of RCU provides a single debugfs file under the
 top-level directory RCU, namely rcu/rcudata, which displays fields in
-rcu_bh_ctrlblk, rcu_sched_ctrlblk and, for CONFIG_TINY_PREEMPT_RCU,
-rcu_preempt_ctrlblk.
+rcu_bh_ctrlblk and rcu_sched_ctrlblk.
 
 The output of "cat rcu/rcudata" is as follows:
 
-rcu_preempt: qlen=24 gp=1097669 g197/p197/c197 tasks=...
-             ttb=. btg=no ntb=184 neb=0 nnb=183 j=01f7 bt=0274
-             normal balk: nt=1097669 gt=0 bt=371 b=0 ny=25073378 nos=0
-             exp balk: bt=0 nos=0
 rcu_sched: qlen: 0
 rcu_bh: qlen: 0
 
-This is split into rcu_preempt, rcu_sched, and rcu_bh sections, with the
-rcu_preempt section appearing only in CONFIG_TINY_PREEMPT_RCU builds.
-The last three lines of the rcu_preempt section appear only in
-CONFIG_RCU_BOOST kernel builds.  The fields are as follows:
+This is split into rcu_sched and rcu_bh sections.  The field is as
+follows:
 
 o      "qlen" is the number of RCU callbacks currently waiting either
        for an RCU grace period or waiting to be invoked.  This is the
        only field present for rcu_sched and rcu_bh, due to the
        short-circuiting of grace period in those two cases.
-
-o      "gp" is the number of grace periods that have completed.
-
-o      "g197/p197/c197" displays the grace-period state, with the
-       "g" number being the number of grace periods that have started
-       (mod 256), the "p" number being the number of grace periods
-       that the CPU has responded to (also mod 256), and the "c"
-       number being the number of grace periods that have completed
-       (once again mode 256).
-
-       Why have both "gp" and "g"?  Because the data flowing into
-       "gp" is only present in a CONFIG_RCU_TRACE kernel.
-
-o      "tasks" is a set of bits.  The first bit is "T" if there are
-       currently tasks that have recently blocked within an RCU
-       read-side critical section, the second bit is "N" if any of the
-       aforementioned tasks are blocking the current RCU grace period,
-       and the third bit is "E" if any of the aforementioned tasks are
-       blocking the current expedited grace period.  Each bit is "."
-       if the corresponding condition does not hold.
-
-o      "ttb" is a single bit.  It is "B" if any of the blocked tasks
-       need to be priority boosted and "." otherwise.
-
-o      "btg" indicates whether boosting has been carried out during
-       the current grace period, with "exp" indicating that boosting
-       is in progress for an expedited grace period, "no" indicating
-       that boosting has not yet started for a normal grace period,
-       "begun" indicating that boosting has bebug for a normal grace
-       period, and "done" indicating that boosting has completed for
-       a normal grace period.
-
-o      "ntb" is the total number of tasks subjected to RCU priority boosting
-       periods since boot.
-
-o      "neb" is the number of expedited grace periods that have had
-       to resort to RCU priority boosting since boot.
-
-o      "nnb" is the number of normal grace periods that have had
-       to resort to RCU priority boosting since boot.
-
-o      "j" is the low-order 16 bits of the jiffies counter in hexadecimal.
-
-o      "bt" is the low-order 16 bits of the value that the jiffies counter
-       will have at the next time that boosting is scheduled to begin.
-
-o      In the line beginning with "normal balk", the fields are as follows:
-
-       o       "nt" is the number of times that the system balked from
-               boosting because there were no blocked tasks to boost.
-               Note that the system will balk from boosting even if the
-               grace period is overdue when the currently running task
-               is looping within an RCU read-side critical section.
-               There is no point in boosting in this case, because
-               boosting a running task won't make it run any faster.
-
-       o       "gt" is the number of times that the system balked
-               from boosting because, although there were blocked tasks,
-               none of them were preventing the current grace period
-               from completing.
-
-       o       "bt" is the number of times that the system balked
-               from boosting because boosting was already in progress.
-
-       o       "b" is the number of times that the system balked from
-               boosting because boosting had already completed for
-               the grace period in question.
-
-       o       "ny" is the number of times that the system balked from
-               boosting because it was not yet time to start boosting
-               the grace period in question.
-
-       o       "nos" is the number of times that the system balked from
-               boosting for inexplicable ("not otherwise specified")
-               reasons.  This can actually happen due to races involving
-               increments of the jiffies counter.
-
-o      In the line beginning with "exp balk", the fields are as follows:
-
-       o       "bt" is the number of times that the system balked from
-               boosting because there were no blocked tasks to boost.
-
-       o       "nos" is the number of times that the system balked from
-                boosting for inexplicable ("not otherwise specified")
-                reasons.