[PATCH tip/core/rcu 83/88] rcu: Remove debugfs tracing

[Paul E. McKenney]

RCU's debugfs tracing used to be the only reasonable low-level debug
information available, but ftrace and event tracing has since surpassed
the RCU debugfs level of usefulness.  This commit therefore removes
RCU's debugfs tracing.

Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
---
 Documentation/RCU/00-INDEX                         |   2 -
 .../RCU/Design/Requirements/Requirements.html      |   2 +-
 Documentation/RCU/trace.txt                        | 535 ---------------------
 init/Kconfig                                       |   8 -
 kernel/rcu/Makefile                                |   1 -
 kernel/rcu/tiny_plugin.h                           |  45 --
 kernel/rcu/tree.h                                  |  27 --
 kernel/rcu/tree_plugin.h                           |  31 +-
 kernel/rcu/tree_trace.c                            | 494 -------------------
 lib/Kconfig.debug                                  |   5 +-
 .../selftests/rcutorture/configs/rcu/TREE02-T      |  21 -
 .../selftests/rcutorture/configs/rcu/TREE08-T      |  21 -
 .../selftests/rcutorture/doc/TREE_RCU-kconfig.txt  |   4 -
 13 files changed, 4 insertions(+), 1192 deletions(-)
 delete mode 100644 Documentation/RCU/trace.txt
 delete mode 100644 kernel/rcu/tree_trace.c
 delete mode 100644 tools/testing/selftests/rcutorture/configs/rcu/TREE02-T
 delete mode 100644 tools/testing/selftests/rcutorture/configs/rcu/TREE08-T

diff --git a/Documentation/RCU/00-INDEX b/Documentation/RCU/00-INDEX
index 1672573b037a..f46980c060aa 100644
--- a/Documentation/RCU/00-INDEX
+++ b/Documentation/RCU/00-INDEX
@@ -28,8 +28,6 @@ stallwarn.txt
 	- RCU CPU stall warnings (module parameter rcu_cpu_stall_suppress)
 torture.txt
 	- RCU Torture Test Operation (CONFIG_RCU_TORTURE_TEST)
-trace.txt
-	- CONFIG_RCU_TRACE debugfs files and formats
 UP.txt
 	- RCU on Uniprocessor Systems
 whatisRCU.txt
diff --git a/Documentation/RCU/Design/Requirements/Requirements.html b/Documentation/RCU/Design/Requirements/Requirements.html
index 0e6550a8c926..95b30fa25d56 100644
--- a/Documentation/RCU/Design/Requirements/Requirements.html
+++ b/Documentation/RCU/Design/Requirements/Requirements.html
@@ -2034,7 +2034,7 @@ guard against mishaps and misuse:
 	some other synchronization mechanism, for example, reference
 	counting.
 <li>	In kernels built with <tt>CONFIG_RCU_TRACE=y</tt>, RCU-related
-	information is provided via both debugfs and event tracing.
+	information is provided via event tracing.
 <li>	Open-coded use of <tt>rcu_assign_pointer()</tt> and
 	<tt>rcu_dereference()</tt> to create typical linked
 	data structures can be surprisingly error-prone.
diff --git a/Documentation/RCU/trace.txt b/Documentation/RCU/trace.txt
deleted file mode 100644
index 6549012033f9..000000000000
--- a/Documentation/RCU/trace.txt
+++ /dev/null
@@ -1,535 +0,0 @@
-CONFIG_RCU_TRACE debugfs Files and Formats
-
-
-The rcutree and rcutiny 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.
-The following sections describe the debugfs files and formats, first
-for rcutree and next for rcutiny.
-
-
-CONFIG_TREE_RCU and CONFIG_PREEMPT_RCU debugfs Files and Formats
-
-These implementations of RCU provide several debugfs directories under the
-top-level directory "rcu":
-
-rcu/rcu_bh
-rcu/rcu_preempt
-rcu/rcu_sched
-
-Each directory contains files for the corresponding flavor of RCU.
-Note that rcu/rcu_preempt is only present for CONFIG_PREEMPT_RCU.
-For CONFIG_TREE_RCU, the RCU flavor maps onto the RCU-sched flavor,
-so that activity for both appears in rcu/rcu_sched.
-
-In addition, the following file appears in the top-level directory:
-rcu/rcutorture.  This file displays rcutorture test progress.  The output
-of "cat rcu/rcutorture" looks as follows:
-
-rcutorture test sequence: 0 (test in progress)
-rcutorture update version number: 615
-
-The first line shows the number of rcutorture tests that have completed
-since boot.  If a test is currently running, the "(test in progress)"
-string will appear as shown above.  The second line shows the number of
-update cycles that the current test has started, or zero if there is
-no test in progress.
-
-
-Within each flavor directory (rcu/rcu_bh, rcu/rcu_sched, and possibly
-also rcu/rcu_preempt) the following files will be present:
-
-rcudata:
-	Displays fields in struct rcu_data.
-rcuexp:
-	Displays statistics for expedited grace periods.
-rcugp:
-	Displays grace-period counters.
-rcuhier:
-	Displays the struct rcu_node hierarchy.
-rcu_pending:
-	Displays counts of the reasons rcu_pending() decided that RCU had
-	work to do.
-rcuboost:
-	Displays RCU boosting statistics.  Only present if
-	CONFIG_RCU_BOOST=y.
-
-The output of "cat rcu/rcu_preempt/rcudata" looks as follows:
-
-  0!c=30455 g=30456 cnq=1/0:1 dt=126535/140000000000000/0 df=2002 of=4 ql=0/0 qs=N... b=10 ci=74572 nci=0 co=1131 ca=716
-  1!c=30719 g=30720 cnq=1/0:0 dt=132007/140000000000000/0 df=1874 of=10 ql=0/0 qs=N... b=10 ci=123209 nci=0 co=685 ca=982
-  2!c=30150 g=30151 cnq=1/1:1 dt=138537/140000000000000/0 df=1707 of=8 ql=0/0 qs=N... b=10 ci=80132 nci=0 co=1328 ca=1458
-  3 c=31249 g=31250 cnq=1/1:0 dt=107255/140000000000000/0 df=1749 of=6 ql=0/450 qs=NRW. b=10 ci=151700 nci=0 co=509 ca=622
-  4!c=29502 g=29503 cnq=1/0:1 dt=83647/140000000000000/0 df=965 of=5 ql=0/0 qs=N... b=10 ci=65643 nci=0 co=1373 ca=1521
-  5 c=31201 g=31202 cnq=1/0:1 dt=70422/0/0 df=535 of=7 ql=0/0 qs=.... b=10 ci=58500 nci=0 co=764 ca=698
-  6!c=30253 g=30254 cnq=1/0:1 dt=95363/140000000000000/0 df=780 of=5 ql=0/0 qs=N... b=10 ci=100607 nci=0 co=1414 ca=1353
-  7 c=31178 g=31178 cnq=1/0:0 dt=91536/0/0 df=547 of=4 ql=0/0 qs=.... b=10 ci=109819 nci=0 co=1115 ca=969
-
-This file has one line per CPU, or eight for this 8-CPU system.
-The fields are as follows:
-
-o	The number at the beginning of each line is the CPU number.
-	CPUs numbers followed by an exclamation mark are offline,
-	but have been online at least once since boot.	There will be
-	no output for CPUs that have never been online, which can be
-	a good thing in the surprisingly common case where NR_CPUS is
-	substantially larger than the number of actual CPUs.
-
-o	"c" is the count of grace periods that this CPU believes have
-	completed.  Offlined CPUs and CPUs in dynticks idle mode may lag
-	quite a ways behind, for example, CPU 4 under "rcu_sched" above,
-	which has been offline through 16 RCU grace periods.  It is not
-	unusual to see offline CPUs lagging by thousands of grace periods.
-	Note that although the grace-period number is an unsigned long,
-	it is printed out as a signed long to allow more human-friendly
-	representation near boot time.
-
-o	"g" is the count of grace periods that this CPU believes have
-	started.  Again, offlined CPUs and CPUs in dynticks idle mode
-	may lag behind.  If the "c" and "g" values are equal, this CPU
-	has already reported a quiescent state for the last RCU grace
-	period that it is aware of, otherwise, the CPU believes that it
-	owes RCU a quiescent state.
-
-o	"pq" indicates that this CPU has passed through a quiescent state
-	for the current grace period.  It is possible for "pq" to be
-	"1" and "c" different than "g", which indicates that although
-	the CPU has passed through a quiescent state, either (1) this
-	CPU has not yet reported that fact, (2) some other CPU has not
-	yet reported for this grace period, or (3) both.
-
-o	"qp" indicates that RCU still expects a quiescent state from
-	this CPU.  Offlined CPUs and CPUs in dyntick idle mode might
-	well have qp=1, which is OK: RCU is still ignoring them.
-
-o	"dt" is the current value of the dyntick counter that is incremented
-	when entering or leaving idle, either due to a context switch or
-	due to an interrupt.  This number is even if the CPU is in idle
-	from RCU's viewpoint and odd otherwise.  The number after the
-	first "/" is the interrupt nesting depth when in idle state,
-	or a large number added to the interrupt-nesting depth when
-	running a non-idle task.  Some architectures do not accurately
-	count interrupt nesting when running in non-idle kernel context,
-	which can result in interesting anomalies such as negative
-	interrupt-nesting levels.  The number after the second "/"
-	is the NMI nesting depth.
-
-o	"df" is the number of times that some other CPU has forced a
-	quiescent state on behalf of this CPU due to this CPU being in
-	idle state.
-
-o	"of" is the number of times that some other CPU has forced a
-	quiescent state on behalf of this CPU due to this CPU being
-	offline.  In a perfect world, this might never happen, but it
-	turns out that offlining and onlining a CPU can take several grace
-	periods, and so there is likely to be an extended period of time
-	when RCU believes that the CPU is online when it really is not.
-	Please note that erring in the other direction (RCU believing a
-	CPU is offline when it is really alive and kicking) is a fatal
-	error, so it makes sense to err conservatively.
-
-o	"ql" is the number of RCU callbacks currently residing on
-	this CPU.  The first number is the number of "lazy" callbacks
-	that are known to RCU to only be freeing memory, and the number
-	after the "/" is the total number of callbacks, lazy or not.
-	These counters count callbacks regardless of what phase of
-	grace-period processing that they are in (new, waiting for
-	grace period to start, waiting for grace period to end, ready
-	to invoke).
-
-o	"qs" gives an indication of the state of the callback queue
-	with four characters:
-
-	"N"	Indicates that there are callbacks queued that are not
-		ready to be handled by the next grace period, and thus
-		will be handled by the grace period following the next
-		one.
-
-	"R"	Indicates that there are callbacks queued that are
-		ready to be handled by the next grace period.
-
-	"W"	Indicates that there are callbacks queued that are
-		waiting on the current grace period.
-
-	"D"	Indicates that there are callbacks queued that have
-		already been handled by a prior grace period, and are
-		thus waiting to be invoked.  Note that callbacks in
-		the process of being invoked are not counted here.
-		Callbacks in the process of being invoked are those
-		that have been removed from the rcu_data structures
-		queues by rcu_do_batch(), but which have not yet been
-		invoked.
-
-	If there are no callbacks in a given one of the above states,
-	the corresponding character is replaced by ".".
-
-o	"b" is the batch limit for this CPU.  If more than this number
-	of RCU callbacks is ready to invoke, then the remainder will
-	be deferred.
-
-o	"ci" is the number of RCU callbacks that have been invoked for
-	this CPU.  Note that ci+nci+ql is the number of callbacks that have
-	been registered in absence of CPU-hotplug activity.
-
-o	"nci" is the number of RCU callbacks that have been offloaded from
-	this CPU.  This will always be zero unless the kernel was built
-	with CONFIG_RCU_NOCB_CPU=y and the "rcu_nocbs=" kernel boot
-	parameter was specified.
-
-o	"co" is the number of RCU callbacks that have been orphaned due to
-	this CPU going offline.  These orphaned callbacks have been moved
-	to an arbitrarily chosen online CPU.
-
-o	"ca" is the number of RCU callbacks that have been adopted by this
-	CPU due to other CPUs going offline.  Note that ci+co-ca+ql is
-	the number of RCU callbacks registered on this CPU.
-
-
-Kernels compiled with CONFIG_RCU_BOOST=y display the following from
-/debug/rcu/rcu_preempt/rcudata:
-
-  0!c=12865 g=12866 cnq=1/0:1 dt=83113/140000000000000/0 df=288 of=11 ql=0/0 qs=N... kt=0/O ktl=944 b=10 ci=60709 nci=0 co=748 ca=871
-  1 c=14407 g=14408 cnq=1/0:0 dt=100679/140000000000000/0 df=378 of=7 ql=0/119 qs=NRW. kt=0/W ktl=9b6 b=10 ci=109740 nci=0 co=589 ca=485
-  2 c=14407 g=14408 cnq=1/0:0 dt=105486/0/0 df=90 of=9 ql=0/89 qs=NRW. kt=0/W ktl=c0c b=10 ci=83113 nci=0 co=533 ca=490
-  3 c=14407 g=14408 cnq=1/0:0 dt=107138/0/0 df=142 of=8 ql=0/188 qs=NRW. kt=0/W ktl=b96 b=10 ci=121114 nci=0 co=426 ca=290
-  4 c=14405 g=14406 cnq=1/0:1 dt=50238/0/0 df=706 of=7 ql=0/0 qs=.... kt=0/W ktl=812 b=10 ci=34929 nci=0 co=643 ca=114
-  5!c=14168 g=14169 cnq=1/0:0 dt=45465/140000000000000/0 df=161 of=11 ql=0/0 qs=N... kt=0/O ktl=b4d b=10 ci=47712 nci=0 co=677 ca=722
-  6 c=14404 g=14405 cnq=1/0:0 dt=59454/0/0 df=94 of=6 ql=0/0 qs=.... kt=0/W ktl=e57 b=10 ci=55597 nci=0 co=701 ca=811
-  7 c=14407 g=14408 cnq=1/0:1 dt=68850/0/0 df=31 of=8 ql=0/0 qs=.... kt=0/W ktl=14bd b=10 ci=77475 nci=0 co=508 ca=1042
-
-This is similar to the output discussed above, but contains the following
-additional fields:
-
-o	"kt" is the per-CPU kernel-thread state.  The digit preceding
-	the first slash is zero if there is no work pending and 1
-	otherwise.  The character between the first pair of slashes is
-	as follows:
-
-	"S"	The kernel thread is stopped, in other words, all
-		CPUs corresponding to this rcu_node structure are
-		offline.
-
-	"R"	The kernel thread is running.
-
-	"W"	The kernel thread is waiting because there is no work
-		for it to do.
-
-	"O"	The kernel thread is waiting because it has been
-		forced off of its designated CPU or because its
-		->cpus_allowed mask permits it to run on other than
-		its designated CPU.
-
-	"Y"	The kernel thread is yielding to avoid hogging CPU.
-
-	"?"	Unknown value, indicates a bug.
-
-	The number after the final slash is the CPU that the kthread
-	is actually running on.
-
-	This field is displayed only for CONFIG_RCU_BOOST kernels.
-
-o	"ktl" is the low-order 16 bits (in hexadecimal) of the count of
-	the number of times that this CPU's per-CPU kthread has gone
-	through its loop servicing invoke_rcu_cpu_kthread() requests.
-
-	This field is displayed only for CONFIG_RCU_BOOST kernels.
-
-
-The output of "cat rcu/rcu_preempt/rcuexp" looks as follows:
-
-s=21872 wd1=0 wd2=0 wd3=5 enq=0 sc=21872
-
-These fields are as follows:
-
-o	"s" is the sequence number, with an odd number indicating that
-	an expedited grace period is in progress.
-
-o	"wd1", "wd2", and "wd3" are the number of times that an attempt
-	to start an expedited grace period found that someone else had
-	completed an expedited grace period that satisfies the attempted
-	request.  "Our work is done."
-
-o	"enq" is the number of quiescent states still outstanding.
-
-o	"sc" is the number of times that the attempt to start a
-	new expedited grace period succeeded.
-
-
-The output of "cat rcu/rcu_preempt/rcugp" looks as follows:
-
-completed=31249  gpnum=31250  age=1  max=18
-
-These fields are taken from the rcu_state structure, and are as follows:
-
-o	"completed" is the number of grace periods that have completed.
-	It is comparable to the "c" field from rcu/rcudata in that a
-	CPU whose "c" field matches the value of "completed" is aware
-	that the corresponding RCU grace period has completed.
-
-o	"gpnum" is the number of grace periods that have started.  It is
-	similarly comparable to the "g" field from rcu/rcudata in that
-	a CPU whose "g" field matches the value of "gpnum" is aware that
-	the corresponding RCU grace period has started.
-
-	If these two fields are equal, then there is no grace period
-	in progress, in other words, RCU is idle.  On the other hand,
-	if the two fields differ (as they are above), then an RCU grace
-	period is in progress.
-
-o	"age" is the number of jiffies that the current grace period
-	has extended for, or zero if there is no grace period currently
-	in effect.
-
-o	"max" is the age in jiffies of the longest-duration grace period
-	thus far.
-
-The output of "cat rcu/rcu_preempt/rcuhier" looks as follows:
-
-c=14407 g=14408 s=0 jfq=2 j=c863 nfqs=12040/nfqsng=0(12040) fqlh=1051 oqlen=0/0
-3/3 ..>. 0:7 ^0
-e/e ..>. 0:3 ^0    d/d ..>. 4:7 ^1
-
-The fields are as follows:
-
-o	"c" is exactly the same as "completed" under rcu/rcu_preempt/rcugp.
-
-o	"g" is exactly the same as "gpnum" under rcu/rcu_preempt/rcugp.
-
-o	"s" is the current state of the force_quiescent_state()
-	state machine.
-
-o	"jfq" is the number of jiffies remaining for this grace period
-	before force_quiescent_state() is invoked to help push things
-	along.	Note that CPUs in idle mode throughout the grace period
-	will not report on their own, but rather must be check by some
-	other CPU via force_quiescent_state().
-
-o	"j" is the low-order four hex digits of the jiffies counter.
-	Yes, Paul did run into a number of problems that turned out to
-	be due to the jiffies counter no longer counting.  Why do you ask?
-
-o	"nfqs" is the number of calls to force_quiescent_state() since
-	boot.
-
-o	"nfqsng" is the number of useless calls to force_quiescent_state(),
-	where there wasn't actually a grace period active.  This can
-	no longer happen due to grace-period processing being pushed
-	into a kthread.  The number in parentheses is the difference
-	between "nfqs" and "nfqsng", or the number of times that
-	force_quiescent_state() actually did some real work.
-
-o	"fqlh" is the number of calls to force_quiescent_state() that
-	exited immediately (without even being counted in nfqs above)
-	due to contention on ->fqslock.
-
-o	Each element of the form "3/3 ..>. 0:7 ^0" represents one rcu_node
-	structure.  Each line represents one level of the hierarchy,
-	from root to leaves.  It is best to think of the rcu_data
-	structures as forming yet another level after the leaves.
-	Note that there might be either one, two, three, or even four
-	levels of rcu_node structures, depending on the relationship
-	between CONFIG_RCU_FANOUT, CONFIG_RCU_FANOUT_LEAF (possibly
-	adjusted using the rcu_fanout_leaf kernel boot parameter), and
-	CONFIG_NR_CPUS (possibly adjusted using the nr_cpu_ids count of
-	possible CPUs for the booting hardware).
-
-	o	The numbers separated by the "/" are the qsmask followed
-		by the qsmaskinit.  The qsmask will have one bit
-		set for each entity in the next lower level that has
-		not yet checked in for the current grace period ("e"
-		indicating CPUs 5, 6, and 7 in the example above).
-		The qsmaskinit will have one bit for each entity that is
-		currently expected to check in during each grace period.
-		The value of qsmaskinit is assigned to that of qsmask
-		at the beginning of each grace period.
-
-	o	The characters separated by the ">" indicate the state
-		of the blocked-tasks lists.  A "G" preceding the ">"
-		indicates that at least one task blocked in an RCU
-		read-side critical section blocks the current grace
-		period, while a "E" preceding the ">" indicates that
-		at least one task blocked in an RCU read-side critical
-		section blocks the current expedited grace period.
-		A "T" character following the ">" indicates that at
-		least one task is blocked within an RCU read-side
-		critical section, regardless of whether any current
-		grace period (expedited or normal) is inconvenienced.
-		A "." character appears if the corresponding condition
-		does not hold, so that "..>." indicates that no tasks
-		are blocked.  In contrast, "GE>T" indicates maximal
-		inconvenience from blocked tasks.  CONFIG_TREE_RCU
-		builds of the kernel will always show "..>.".
-
-	o	The numbers separated by the ":" are the range of CPUs
-		served by this struct rcu_node.  This can be helpful
-		in working out how the hierarchy is wired together.
-
-		For example, the example rcu_node structure shown above
-		has "0:7", indicating that it covers CPUs 0 through 7.
-
-	o	The number after the "^" indicates the bit in the
-		next higher level rcu_node structure that this rcu_node
-		structure corresponds to.  For example, the "d/d ..>. 4:7
-		^1" has a "1" in this position, indicating that it
-		corresponds to the "1" bit in the "3" shown in the
-		"3/3 ..>. 0:7 ^0" entry on the next level up.
-
-
-The output of "cat rcu/rcu_sched/rcu_pending" looks as follows:
-
-  0!np=26111 qsp=29 rpq=5386 cbr=1 cng=570 gpc=3674 gps=577 nn=15903 ndw=0
-  1!np=28913 qsp=35 rpq=6097 cbr=1 cng=448 gpc=3700 gps=554 nn=18113 ndw=0
-  2!np=32740 qsp=37 rpq=6202 cbr=0 cng=476 gpc=4627 gps=546 nn=20889 ndw=0
-  3 np=23679 qsp=22 rpq=5044 cbr=1 cng=415 gpc=3403 gps=347 nn=14469 ndw=0
-  4!np=30714 qsp=4 rpq=5574 cbr=0 cng=528 gpc=3931 gps=639 nn=20042 ndw=0
-  5 np=28910 qsp=2 rpq=5246 cbr=0 cng=428 gpc=4105 gps=709 nn=18422 ndw=0
-  6!np=38648 qsp=5 rpq=7076 cbr=0 cng=840 gpc=4072 gps=961 nn=25699 ndw=0
-  7 np=37275 qsp=2 rpq=6873 cbr=0 cng=868 gpc=3416 gps=971 nn=25147 ndw=0
-
-The fields are as follows:
-
-o	The leading number is the CPU number, with "!" indicating
-	an offline CPU.
-
-o	"np" is the number of times that __rcu_pending() has been invoked
-	for the corresponding flavor of RCU.
-
-o	"qsp" is the number of times that the RCU was waiting for a
-	quiescent state from this CPU.
-
-o	"rpq" is the number of times that the CPU had passed through
-	a quiescent state, but not yet reported it to RCU.
-
-o	"cbr" is the number of times that this CPU had RCU callbacks
-	that had passed through a grace period, and were thus ready
-	to be invoked.
-
-o	"cng" is the number of times that this CPU needed another
-	grace period while RCU was idle.
-
-o	"gpc" is the number of times that an old grace period had
-	completed, but this CPU was not yet aware of it.
-
-o	"gps" is the number of times that a new grace period had started,
-	but this CPU was not yet aware of it.
-
-o	"ndw" is the number of times that a wakeup of an rcuo
-	callback-offload kthread had to be deferred in order to avoid
-	deadlock.
-
-o	"nn" is the number of times that this CPU needed nothing.
-
-
-The output of "cat rcu/rcuboost" looks as follows:
-
-0:3 tasks=.... kt=W ntb=0 neb=0 nnb=0 j=c864 bt=c894
-    balk: nt=0 egt=4695 bt=0 nb=0 ny=56 nos=0
-4:7 tasks=.... kt=W ntb=0 neb=0 nnb=0 j=c864 bt=c894
-    balk: nt=0 egt=6541 bt=0 nb=0 ny=126 nos=0
-
-This information is output only for rcu_preempt.  Each two-line entry
-corresponds to a leaf rcu_node structure.  The fields are as follows:
-
-o	"n:m" is the CPU-number range for the corresponding two-line
-	entry.  In the sample output above, the first entry covers
-	CPUs zero through three and the second entry covers CPUs four
-	through seven.
-
-o	"tasks=TNEB" gives the state of the various segments of the
-	rnp->blocked_tasks list:
-
-	"T"	This indicates that there are some tasks that blocked
-		while running on one of the corresponding CPUs while
-		in an RCU read-side critical section.
-
-	"N"	This indicates that some of the blocked tasks are preventing
-		the current normal (non-expedited) grace period from
-		completing.
-
-	"E"	This indicates that some of the blocked tasks are preventing
-		the current expedited grace period from completing.
-
-	"B"	This indicates that some of the blocked tasks are in
-		need of RCU priority boosting.
-
-	Each character is replaced with "." if the corresponding
-	condition does not hold.
-
-o	"kt" is the state of the RCU priority-boosting kernel
-	thread associated with the corresponding rcu_node structure.
-	The state can be one of the following:
-
-	"S"	The kernel thread is stopped, in other words, all
-		CPUs corresponding to this rcu_node structure are
-		offline.
-
-	"R"	The kernel thread is running.
-
-	"W"	The kernel thread is waiting because there is no work
-		for it to do.
-
-	"Y"	The kernel thread is yielding to avoid hogging CPU.
-
-	"?"	Unknown value, indicates a bug.
-
-o	"ntb" is the number of tasks boosted.
-
-o	"neb" is the number of tasks boosted in order to complete an
-	expedited grace period.
-
-o	"nnb" is the number of tasks boosted in order to complete a
-	normal (non-expedited) grace period.  When boosting a task
-	that was blocking both an expedited and a normal grace period,
-	it is counted against the expedited total above.
-
-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 when we next start boosting, assuming that
-	the current grace period does not end beforehand.  This is
-	also in hexadecimal.
-
-o	"balk: nt" counts the number of times we didn't boost (in
-	other words, we balked) even though it was time to boost because
-	there were no blocked tasks to boost.  This situation occurs
-	when there is one blocked task on one rcu_node structure and
-	none on some other rcu_node structure.
-
-o	"egt" counts the number of times we balked because although
-	there were blocked tasks, none of them were blocking the
-	current grace period, whether expedited or otherwise.
-
-o	"bt" counts the number of times we balked because boosting
-	had already been initiated for the current grace period.
-
-o	"nb" counts the number of times we balked because there
-	was at least one task blocking the current non-expedited grace
-	period that never had blocked.  If it is already running, it
-	just won't help to boost its priority!
-
-o	"ny" counts the number of times we balked because it was
-	not yet time to start boosting.
-
-o	"nos" counts the number of times we balked for other
-	reasons, e.g., the grace period ended first.
-
-
-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 and rcu_sched_ctrlblk.
-
-The output of "cat rcu/rcudata" is as follows:
-
-rcu_sched: qlen: 0
-rcu_bh: qlen: 0
-
-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.
diff --git a/init/Kconfig b/init/Kconfig
index 2aa14ff40e88..3025383ab443 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -659,14 +659,6 @@ config RCU_FAST_NO_HZ
 
 	  Say N if you are unsure.
 
-config TREE_RCU_TRACE
-	def_bool RCU_TRACE && ( TREE_RCU || PREEMPT_RCU )
-	select DEBUG_FS
-	help
-	  This option provides tracing for the TREE_RCU and
-	  PREEMPT_RCU implementations, permitting Makefile to
-	  trivially select kernel/rcutree_trace.c.
-
 config RCU_BOOST
 	bool "Enable RCU priority boosting"
 	depends on RT_MUTEXES && PREEMPT_RCU && RCU_EXPERT
diff --git a/kernel/rcu/Makefile b/kernel/rcu/Makefile
index 3945337c8ce4..13c0fc852767 100644
--- a/kernel/rcu/Makefile
+++ b/kernel/rcu/Makefile
@@ -9,6 +9,5 @@ obj-$(CONFIG_RCU_TORTURE_TEST) += rcutorture.o
 obj-$(CONFIG_RCU_PERF_TEST) += rcuperf.o
 obj-$(CONFIG_TREE_RCU) += tree.o
 obj-$(CONFIG_PREEMPT_RCU) += tree.o
-obj-$(CONFIG_TREE_RCU_TRACE) += tree_trace.o
 obj-$(CONFIG_TINY_RCU) += tiny.o
 obj-$(CONFIG_RCU_NEED_SEGCBLIST) += rcu_segcblist.o
diff --git a/kernel/rcu/tiny_plugin.h b/kernel/rcu/tiny_plugin.h
index 371034e77f87..c642f23f1582 100644
--- a/kernel/rcu/tiny_plugin.h
+++ b/kernel/rcu/tiny_plugin.h
@@ -24,8 +24,6 @@
 
 #include <linux/kthread.h>
 #include <linux/init.h>
-#include <linux/debugfs.h>
-#include <linux/seq_file.h>
 
 /* Global control variables for rcupdate callback mechanism. */
 struct rcu_ctrlblk {
@@ -87,49 +85,6 @@ static void rcu_trace_sub_qlen(struct rcu_ctrlblk *rcp, int n)
 	local_irq_restore(flags);
 }
 
-/*
- * Dump statistics for TINY_RCU, such as they are.
- */
-static int show_tiny_stats(struct seq_file *m, void *unused)
-{
-	seq_printf(m, "rcu_sched: qlen: %ld\n", rcu_sched_ctrlblk.qlen);
-	seq_printf(m, "rcu_bh: qlen: %ld\n", rcu_bh_ctrlblk.qlen);
-	return 0;
-}
-
-static int show_tiny_stats_open(struct inode *inode, struct file *file)
-{
-	return single_open(file, show_tiny_stats, NULL);
-}
-
-static const struct file_operations show_tiny_stats_fops = {
-	.owner = THIS_MODULE,
-	.open = show_tiny_stats_open,
-	.read = seq_read,
-	.llseek = seq_lseek,
-	.release = single_release,
-};
-
-static struct dentry *rcudir;
-
-static int __init rcutiny_trace_init(void)
-{
-	struct dentry *retval;
-
-	rcudir = debugfs_create_dir("rcu", NULL);
-	if (!rcudir)
-		goto free_out;
-	retval = debugfs_create_file("rcudata", 0444, rcudir,
-				     NULL, &show_tiny_stats_fops);
-	if (!retval)
-		goto free_out;
-	return 0;
-free_out:
-	debugfs_remove_recursive(rcudir);
-	return 1;
-}
-device_initcall(rcutiny_trace_init);
-
 static void check_cpu_stall(struct rcu_ctrlblk *rcp)
 {
 	unsigned long j;
diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h
index 2c112bb11aa8..9af0f31d6847 100644
--- a/kernel/rcu/tree.h
+++ b/kernel/rcu/tree.h
@@ -152,19 +152,6 @@ struct rcu_node {
 				/* Number of tasks boosted for expedited GP. */
 	unsigned long n_normal_boosts;
 				/* Number of tasks boosted for normal GP. */
-	unsigned long n_balk_blkd_tasks;
-				/* Refused to boost: no blocked tasks. */
-	unsigned long n_balk_exp_gp_tasks;
-				/* Refused to boost: nothing blocking GP. */
-	unsigned long n_balk_boost_tasks;
-				/* Refused to boost: already boosting. */
-	unsigned long n_balk_notblocked;
-				/* Refused to boost: RCU RS CS still running. */
-	unsigned long n_balk_notyet;
-				/* Refused to boost: not yet time. */
-	unsigned long n_balk_nos;
-				/* Refused to boost: not sure why, though. */
-				/*  This can happen due to race conditions. */
 #ifdef CONFIG_RCU_NOCB_CPU
 	struct swait_queue_head nocb_gp_wq[2];
 				/* Place for rcu_nocb_kthread() to wait GP. */
@@ -535,17 +522,3 @@ void srcu_offline_cpu(unsigned int cpu) { }
 #endif /* #else #ifdef CONFIG_SRCU */
 
 #endif /* #ifndef RCU_TREE_NONCORE */
-
-#ifdef CONFIG_RCU_TRACE
-/* Read out queue lengths for tracing. */
-static inline void rcu_nocb_q_lengths(struct rcu_data *rdp, long *ql, long *qll)
-{
-#ifdef CONFIG_RCU_NOCB_CPU
-	*ql = atomic_long_read(&rdp->nocb_q_count);
-	*qll = atomic_long_read(&rdp->nocb_q_count_lazy);
-#else /* #ifdef CONFIG_RCU_NOCB_CPU */
-	*ql = 0;
-	*qll = 0;
-#endif /* #else #ifdef CONFIG_RCU_NOCB_CPU */
-}
-#endif /* #ifdef CONFIG_RCU_TRACE */
diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
index 7f5919ab24c4..43f2f8026b4a 100644
--- a/kernel/rcu/tree_plugin.h
+++ b/kernel/rcu/tree_plugin.h
@@ -70,7 +70,7 @@ static bool __read_mostly rcu_nocb_poll;    /* Offload kthread are to poll. */
 static void __init rcu_bootup_announce_oddness(void)
 {
 	if (IS_ENABLED(CONFIG_RCU_TRACE))
-		pr_info("\tRCU debugfs-based tracing is enabled.\n");
+		pr_info("\tRCU event tracing is enabled.\n");
 	if ((IS_ENABLED(CONFIG_64BIT) && RCU_FANOUT != 64) ||
 	    (!IS_ENABLED(CONFIG_64BIT) && RCU_FANOUT != 32))
 		pr_info("\tCONFIG_RCU_FANOUT set to non-default value of %d\n",
@@ -899,33 +899,6 @@ void exit_rcu(void)
 
 #include "../locking/rtmutex_common.h"
 
-#ifdef CONFIG_RCU_TRACE
-
-static void rcu_initiate_boost_trace(struct rcu_node *rnp)
-{
-	if (!rcu_preempt_has_tasks(rnp))
-		rnp->n_balk_blkd_tasks++;
-	else if (rnp->exp_tasks == NULL && rnp->gp_tasks == NULL)
-		rnp->n_balk_exp_gp_tasks++;
-	else if (rnp->gp_tasks != NULL && rnp->boost_tasks != NULL)
-		rnp->n_balk_boost_tasks++;
-	else if (rnp->gp_tasks != NULL && rnp->qsmask != 0)
-		rnp->n_balk_notblocked++;
-	else if (rnp->gp_tasks != NULL &&
-		 ULONG_CMP_LT(jiffies, rnp->boost_time))
-		rnp->n_balk_notyet++;
-	else
-		rnp->n_balk_nos++;
-}
-
-#else /* #ifdef CONFIG_RCU_TRACE */
-
-static void rcu_initiate_boost_trace(struct rcu_node *rnp)
-{
-}
-
-#endif /* #else #ifdef CONFIG_RCU_TRACE */
-
 static void rcu_wake_cond(struct task_struct *t, int status)
 {
 	/*
@@ -1058,7 +1031,6 @@ static void rcu_initiate_boost(struct rcu_node *rnp, unsigned long flags)
 
 	lockdep_assert_held(&rnp->lock);
 	if (!rcu_preempt_blocked_readers_cgp(rnp) && rnp->exp_tasks == NULL) {
-		rnp->n_balk_exp_gp_tasks++;
 		raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
 		return;
 	}
@@ -1074,7 +1046,6 @@ static void rcu_initiate_boost(struct rcu_node *rnp, unsigned long flags)
 		if (t)
 			rcu_wake_cond(t, rnp->boost_kthread_status);
 	} else {
-		rcu_initiate_boost_trace(rnp);
 		raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
 	}
 }
diff --git a/kernel/rcu/tree_trace.c b/kernel/rcu/tree_trace.c
deleted file mode 100644
index 6cea17a1ea30..000000000000
--- a/kernel/rcu/tree_trace.c
+++ /dev/null
@@ -1,494 +0,0 @@
-/*
- * Read-Copy Update tracing for hierarchical implementation.
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, you can access it online at
- * http://www.gnu.org/licenses/gpl-2.0.html.
- *
- * Copyright IBM Corporation, 2008
- * Author: Paul E. McKenney
- *
- * Papers:  http://www.rdrop.com/users/paulmck/RCU
- *
- * For detailed explanation of Read-Copy Update mechanism see -
- *		Documentation/RCU
- *
- */
-#include <linux/types.h>
-#include <linux/kernel.h>
-#include <linux/init.h>
-#include <linux/spinlock.h>
-#include <linux/smp.h>
-#include <linux/rcupdate.h>
-#include <linux/interrupt.h>
-#include <linux/sched.h>
-#include <linux/atomic.h>
-#include <linux/bitops.h>
-#include <linux/completion.h>
-#include <linux/percpu.h>
-#include <linux/notifier.h>
-#include <linux/cpu.h>
-#include <linux/mutex.h>
-#include <linux/debugfs.h>
-#include <linux/seq_file.h>
-#include <linux/prefetch.h>
-
-#define RCU_TREE_NONCORE
-#include "tree.h"
-#include "rcu.h"
-
-static int r_open(struct inode *inode, struct file *file,
-					const struct seq_operations *op)
-{
-	int ret = seq_open(file, op);
-	if (!ret) {
-		struct seq_file *m = (struct seq_file *)file->private_data;
-		m->private = inode->i_private;
-	}
-	return ret;
-}
-
-static void *r_start(struct seq_file *m, loff_t *pos)
-{
-	struct rcu_state *rsp = (struct rcu_state *)m->private;
-	*pos = cpumask_next(*pos - 1, cpu_possible_mask);
-	if ((*pos) < nr_cpu_ids)
-		return per_cpu_ptr(rsp->rda, *pos);
-	return NULL;
-}
-
-static void *r_next(struct seq_file *m, void *v, loff_t *pos)
-{
-	(*pos)++;
-	return r_start(m, pos);
-}
-
-static void r_stop(struct seq_file *m, void *v)
-{
-}
-
-static int show_rcubarrier(struct seq_file *m, void *v)
-{
-	struct rcu_state *rsp = (struct rcu_state *)m->private;
-	seq_printf(m, "bcc: %d bseq: %lu\n",
-		   atomic_read(&rsp->barrier_cpu_count),
-		   rsp->barrier_sequence);
-	return 0;
-}
-
-static int rcubarrier_open(struct inode *inode, struct file *file)
-{
-	return single_open(file, show_rcubarrier, inode->i_private);
-}
-
-static const struct file_operations rcubarrier_fops = {
-	.owner = THIS_MODULE,
-	.open = rcubarrier_open,
-	.read = seq_read,
-	.llseek = no_llseek,
-	.release = single_release,
-};
-
-#ifdef CONFIG_RCU_BOOST
-
-static char convert_kthread_status(unsigned int kthread_status)
-{
-	if (kthread_status > RCU_KTHREAD_MAX)
-		return '?';
-	return "SRWOY"[kthread_status];
-}
-
-#endif /* #ifdef CONFIG_RCU_BOOST */
-
-static void print_one_rcu_data(struct seq_file *m, struct rcu_data *rdp)
-{
-	long ql, qll;
-
-	if (!rdp->beenonline)
-		return;
-	seq_printf(m, "%3d%cc=%ld g=%ld cnq=%d/%d:%d",
-		   rdp->cpu,
-		   cpu_is_offline(rdp->cpu) ? '!' : ' ',
-		   ulong2long(rdp->completed), ulong2long(rdp->gpnum),
-		   rdp->cpu_no_qs.b.norm,
-		   rdp->rcu_qs_ctr_snap == per_cpu(rdp->dynticks->rcu_qs_ctr, rdp->cpu),
-		   rdp->core_needs_qs);
-	seq_printf(m, " dt=%d/%llx/%d df=%lu",
-		   rcu_dynticks_snap(rdp->dynticks),
-		   rdp->dynticks->dynticks_nesting,
-		   rdp->dynticks->dynticks_nmi_nesting,
-		   rdp->dynticks_fqs);
-	seq_printf(m, " of=%lu", rdp->offline_fqs);
-	rcu_nocb_q_lengths(rdp, &ql, &qll);
-	qll += rcu_segcblist_n_lazy_cbs(&rdp->cblist);
-	ql += rcu_segcblist_n_cbs(&rdp->cblist);
-	seq_printf(m, " ql=%ld/%ld qs=%c%c%c%c",
-		   qll, ql,
-		   ".N"[!rcu_segcblist_segempty(&rdp->cblist, RCU_NEXT_TAIL)],
-		   ".R"[!rcu_segcblist_segempty(&rdp->cblist,
-						RCU_NEXT_READY_TAIL)],
-		   ".W"[!rcu_segcblist_segempty(&rdp->cblist, RCU_WAIT_TAIL)],
-		   ".D"[!rcu_segcblist_segempty(&rdp->cblist, RCU_DONE_TAIL)]);
-#ifdef CONFIG_RCU_BOOST
-	seq_printf(m, " kt=%d/%c ktl=%x",
-		   per_cpu(rcu_cpu_has_work, rdp->cpu),
-		   convert_kthread_status(per_cpu(rcu_cpu_kthread_status,
-					  rdp->cpu)),
-		   per_cpu(rcu_cpu_kthread_loops, rdp->cpu) & 0xffff);
-#endif /* #ifdef CONFIG_RCU_BOOST */
-	seq_printf(m, " b=%ld", rdp->blimit);
-	seq_printf(m, " ci=%lu nci=%lu co=%lu ca=%lu\n",
-		   rdp->n_cbs_invoked, rdp->n_nocbs_invoked,
-		   rdp->n_cbs_orphaned, rdp->n_cbs_adopted);
-}
-
-static int show_rcudata(struct seq_file *m, void *v)
-{
-	print_one_rcu_data(m, (struct rcu_data *)v);
-	return 0;
-}
-
-static const struct seq_operations rcudate_op = {
-	.start = r_start,
-	.next  = r_next,
-	.stop  = r_stop,
-	.show  = show_rcudata,
-};
-
-static int rcudata_open(struct inode *inode, struct file *file)
-{
-	return r_open(inode, file, &rcudate_op);
-}
-
-static const struct file_operations rcudata_fops = {
-	.owner = THIS_MODULE,
-	.open = rcudata_open,
-	.read = seq_read,
-	.llseek = no_llseek,
-	.release = seq_release,
-};
-
-static int show_rcuexp(struct seq_file *m, void *v)
-{
-	int cpu;
-	struct rcu_state *rsp = (struct rcu_state *)m->private;
-	struct rcu_data *rdp;
-	unsigned long s0 = 0, s1 = 0, s2 = 0, s3 = 0;
-
-	for_each_possible_cpu(cpu) {
-		rdp = per_cpu_ptr(rsp->rda, cpu);
-		s0 += atomic_long_read(&rdp->exp_workdone0);
-		s1 += atomic_long_read(&rdp->exp_workdone1);
-		s2 += atomic_long_read(&rdp->exp_workdone2);
-		s3 += atomic_long_read(&rdp->exp_workdone3);
-	}
-	seq_printf(m, "s=%lu wd0=%lu wd1=%lu wd2=%lu wd3=%lu enq=%d sc=%lu\n",
-		   rsp->expedited_sequence, s0, s1, s2, s3,
-		   atomic_read(&rsp->expedited_need_qs),
-		   rsp->expedited_sequence / 2);
-	return 0;
-}
-
-static int rcuexp_open(struct inode *inode, struct file *file)
-{
-	return single_open(file, show_rcuexp, inode->i_private);
-}
-
-static const struct file_operations rcuexp_fops = {
-	.owner = THIS_MODULE,
-	.open = rcuexp_open,
-	.read = seq_read,
-	.llseek = no_llseek,
-	.release = single_release,
-};
-
-#ifdef CONFIG_RCU_BOOST
-
-static void print_one_rcu_node_boost(struct seq_file *m, struct rcu_node *rnp)
-{
-	seq_printf(m, "%d:%d tasks=%c%c%c%c kt=%c ntb=%lu neb=%lu nnb=%lu ",
-		   rnp->grplo, rnp->grphi,
-		   "T."[list_empty(&rnp->blkd_tasks)],
-		   "N."[!rnp->gp_tasks],
-		   "E."[!rnp->exp_tasks],
-		   "B."[!rnp->boost_tasks],
-		   convert_kthread_status(rnp->boost_kthread_status),
-		   rnp->n_tasks_boosted, rnp->n_exp_boosts,
-		   rnp->n_normal_boosts);
-	seq_printf(m, "j=%04x bt=%04x\n",
-		   (int)(jiffies & 0xffff),
-		   (int)(rnp->boost_time & 0xffff));
-	seq_printf(m, "    balk: nt=%lu egt=%lu bt=%lu nb=%lu ny=%lu nos=%lu\n",
-		   rnp->n_balk_blkd_tasks,
-		   rnp->n_balk_exp_gp_tasks,
-		   rnp->n_balk_boost_tasks,
-		   rnp->n_balk_notblocked,
-		   rnp->n_balk_notyet,
-		   rnp->n_balk_nos);
-}
-
-static int show_rcu_node_boost(struct seq_file *m, void *unused)
-{
-	struct rcu_node *rnp;
-
-	rcu_for_each_leaf_node(&rcu_preempt_state, rnp)
-		print_one_rcu_node_boost(m, rnp);
-	return 0;
-}
-
-static int rcu_node_boost_open(struct inode *inode, struct file *file)
-{
-	return single_open(file, show_rcu_node_boost, NULL);
-}
-
-static const struct file_operations rcu_node_boost_fops = {
-	.owner = THIS_MODULE,
-	.open = rcu_node_boost_open,
-	.read = seq_read,
-	.llseek = no_llseek,
-	.release = single_release,
-};
-
-#endif /* #ifdef CONFIG_RCU_BOOST */
-
-static void print_one_rcu_state(struct seq_file *m, struct rcu_state *rsp)
-{
-	unsigned long gpnum;
-	int level = 0;
-	struct rcu_node *rnp;
-
-	gpnum = rsp->gpnum;
-	seq_printf(m, "c=%ld g=%ld s=%d jfq=%ld j=%x ",
-		   ulong2long(rsp->completed), ulong2long(gpnum),
-		   rsp->gp_state,
-		   (long)(rsp->jiffies_force_qs - jiffies),
-		   (int)(jiffies & 0xffff));
-	seq_printf(m, "nfqs=%lu/nfqsng=%lu(%lu) fqlh=%lu oqlen=%ld/%ld\n",
-		   rsp->n_force_qs, rsp->n_force_qs_ngp,
-		   rsp->n_force_qs - rsp->n_force_qs_ngp,
-		   READ_ONCE(rsp->n_force_qs_lh),
-		   rsp->orphan_done.len_lazy,
-		   rsp->orphan_done.len);
-	for (rnp = &rsp->node[0]; rnp - &rsp->node[0] < rcu_num_nodes; rnp++) {
-		if (rnp->level != level) {
-			seq_puts(m, "\n");
-			level = rnp->level;
-		}
-		seq_printf(m, "%lx/%lx->%lx %c%c>%c %d:%d ^%d    ",
-			   rnp->qsmask, rnp->qsmaskinit, rnp->qsmaskinitnext,
-			   ".G"[rnp->gp_tasks != NULL],
-			   ".E"[rnp->exp_tasks != NULL],
-			   ".T"[!list_empty(&rnp->blkd_tasks)],
-			   rnp->grplo, rnp->grphi, rnp->grpnum);
-	}
-	seq_puts(m, "\n");
-}
-
-static int show_rcuhier(struct seq_file *m, void *v)
-{
-	struct rcu_state *rsp = (struct rcu_state *)m->private;
-	print_one_rcu_state(m, rsp);
-	return 0;
-}
-
-static int rcuhier_open(struct inode *inode, struct file *file)
-{
-	return single_open(file, show_rcuhier, inode->i_private);
-}
-
-static const struct file_operations rcuhier_fops = {
-	.owner = THIS_MODULE,
-	.open = rcuhier_open,
-	.read = seq_read,
-	.llseek = no_llseek,
-	.release = single_release,
-};
-
-static void show_one_rcugp(struct seq_file *m, struct rcu_state *rsp)
-{
-	unsigned long flags;
-	unsigned long completed;
-	unsigned long gpnum;
-	unsigned long gpage;
-	unsigned long gpmax;
-	struct rcu_node *rnp = &rsp->node[0];
-
-	raw_spin_lock_irqsave_rcu_node(rnp, flags);
-	completed = READ_ONCE(rsp->completed);
-	gpnum = READ_ONCE(rsp->gpnum);
-	if (completed == gpnum)
-		gpage = 0;
-	else
-		gpage = jiffies - rsp->gp_start;
-	gpmax = rsp->gp_max;
-	raw_spin_unlock_irqrestore(&rnp->lock, flags);
-	seq_printf(m, "completed=%ld  gpnum=%ld  age=%ld  max=%ld\n",
-		   ulong2long(completed), ulong2long(gpnum), gpage, gpmax);
-}
-
-static int show_rcugp(struct seq_file *m, void *v)
-{
-	struct rcu_state *rsp = (struct rcu_state *)m->private;
-	show_one_rcugp(m, rsp);
-	return 0;
-}
-
-static int rcugp_open(struct inode *inode, struct file *file)
-{
-	return single_open(file, show_rcugp, inode->i_private);
-}
-
-static const struct file_operations rcugp_fops = {
-	.owner = THIS_MODULE,
-	.open = rcugp_open,
-	.read = seq_read,
-	.llseek = no_llseek,
-	.release = single_release,
-};
-
-static void print_one_rcu_pending(struct seq_file *m, struct rcu_data *rdp)
-{
-	if (!rdp->beenonline)
-		return;
-	seq_printf(m, "%3d%cnp=%ld ",
-		   rdp->cpu,
-		   cpu_is_offline(rdp->cpu) ? '!' : ' ',
-		   rdp->n_rcu_pending);
-	seq_printf(m, "qsp=%ld rpq=%ld cbr=%ld cng=%ld ",
-		   rdp->n_rp_core_needs_qs,
-		   rdp->n_rp_report_qs,
-		   rdp->n_rp_cb_ready,
-		   rdp->n_rp_cpu_needs_gp);
-	seq_printf(m, "gpc=%ld gps=%ld nn=%ld ndw%ld\n",
-		   rdp->n_rp_gp_completed,
-		   rdp->n_rp_gp_started,
-		   rdp->n_rp_nocb_defer_wakeup,
-		   rdp->n_rp_need_nothing);
-}
-
-static int show_rcu_pending(struct seq_file *m, void *v)
-{
-	print_one_rcu_pending(m, (struct rcu_data *)v);
-	return 0;
-}
-
-static const struct seq_operations rcu_pending_op = {
-	.start = r_start,
-	.next  = r_next,
-	.stop  = r_stop,
-	.show  = show_rcu_pending,
-};
-
-static int rcu_pending_open(struct inode *inode, struct file *file)
-{
-	return r_open(inode, file, &rcu_pending_op);
-}
-
-static const struct file_operations rcu_pending_fops = {
-	.owner = THIS_MODULE,
-	.open = rcu_pending_open,
-	.read = seq_read,
-	.llseek = no_llseek,
-	.release = seq_release,
-};
-
-static int show_rcutorture(struct seq_file *m, void *unused)
-{
-	seq_printf(m, "rcutorture test sequence: %lu %s\n",
-		   rcutorture_testseq >> 1,
-		   (rcutorture_testseq & 0x1) ? "(test in progress)" : "");
-	seq_printf(m, "rcutorture update version number: %lu\n",
-		   rcutorture_vernum);
-	return 0;
-}
-
-static int rcutorture_open(struct inode *inode, struct file *file)
-{
-	return single_open(file, show_rcutorture, NULL);
-}
-
-static const struct file_operations rcutorture_fops = {
-	.owner = THIS_MODULE,
-	.open = rcutorture_open,
-	.read = seq_read,
-	.llseek = seq_lseek,
-	.release = single_release,
-};
-
-static struct dentry *rcudir;
-
-static int __init rcutree_trace_init(void)
-{
-	struct rcu_state *rsp;
-	struct dentry *retval;
-	struct dentry *rspdir;
-
-	rcudir = debugfs_create_dir("rcu", NULL);
-	if (!rcudir)
-		goto free_out;
-
-	for_each_rcu_flavor(rsp) {
-		rspdir = debugfs_create_dir(rsp->name, rcudir);
-		if (!rspdir)
-			goto free_out;
-
-		retval = debugfs_create_file("rcudata", 0444,
-				rspdir, rsp, &rcudata_fops);
-		if (!retval)
-			goto free_out;
-
-		retval = debugfs_create_file("rcuexp", 0444,
-				rspdir, rsp, &rcuexp_fops);
-		if (!retval)
-			goto free_out;
-
-		retval = debugfs_create_file("rcu_pending", 0444,
-				rspdir, rsp, &rcu_pending_fops);
-		if (!retval)
-			goto free_out;
-
-		retval = debugfs_create_file("rcubarrier", 0444,
-				rspdir, rsp, &rcubarrier_fops);
-		if (!retval)
-			goto free_out;
-
-#ifdef CONFIG_RCU_BOOST
-		if (rsp == &rcu_preempt_state) {
-			retval = debugfs_create_file("rcuboost", 0444,
-				rspdir, NULL, &rcu_node_boost_fops);
-			if (!retval)
-				goto free_out;
-		}
-#endif
-
-		retval = debugfs_create_file("rcugp", 0444,
-				rspdir, rsp, &rcugp_fops);
-		if (!retval)
-			goto free_out;
-
-		retval = debugfs_create_file("rcuhier", 0444,
-				rspdir, rsp, &rcuhier_fops);
-		if (!retval)
-			goto free_out;
-	}
-
-	retval = debugfs_create_file("rcutorture", 0444, rcudir,
-						NULL, &rcutorture_fops);
-	if (!retval)
-		goto free_out;
-	return 0;
-free_out:
-	debugfs_remove_recursive(rcudir);
-	return 1;
-}
-device_initcall(rcutree_trace_init);
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 498d5dd63bf4..8c10b5a97b9e 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -1361,9 +1361,8 @@ config RCU_TRACE
 	default y if TREE_RCU
 	select TRACE_CLOCK
 	help
-	  This option provides tracing in RCU which presents stats
-	  in debugfs for debugging RCU implementation.  It also enables
-	  additional tracepoints for ftrace-style event tracing.
+	  This option enables additional tracepoints for ftrace-style
+	  event tracing.
 
 	  Say Y here if you want to enable RCU tracing
 	  Say N if you are unsure.
diff --git a/tools/testing/selftests/rcutorture/configs/rcu/TREE02-T b/tools/testing/selftests/rcutorture/configs/rcu/TREE02-T
deleted file mode 100644
index 917d2517b5b5..000000000000
--- a/tools/testing/selftests/rcutorture/configs/rcu/TREE02-T
+++ /dev/null
@@ -1,21 +0,0 @@
-CONFIG_SMP=y
-CONFIG_NR_CPUS=8
-CONFIG_PREEMPT_NONE=n
-CONFIG_PREEMPT_VOLUNTARY=n
-CONFIG_PREEMPT=y
-#CHECK#CONFIG_PREEMPT_RCU=y
-CONFIG_HZ_PERIODIC=n
-CONFIG_NO_HZ_IDLE=y
-CONFIG_NO_HZ_FULL=n
-CONFIG_RCU_FAST_NO_HZ=n
-CONFIG_RCU_TRACE=y
-CONFIG_HOTPLUG_CPU=n
-CONFIG_SUSPEND=n
-CONFIG_HIBERNATION=n
-CONFIG_RCU_FANOUT=3
-CONFIG_RCU_FANOUT_LEAF=3
-CONFIG_RCU_NOCB_CPU=n
-CONFIG_DEBUG_LOCK_ALLOC=y
-CONFIG_PROVE_LOCKING=n
-CONFIG_RCU_BOOST=n
-CONFIG_DEBUG_OBJECTS_RCU_HEAD=n
diff --git a/tools/testing/selftests/rcutorture/configs/rcu/TREE08-T b/tools/testing/selftests/rcutorture/configs/rcu/TREE08-T
deleted file mode 100644
index 2ad13f0d29cc..000000000000
--- a/tools/testing/selftests/rcutorture/configs/rcu/TREE08-T
+++ /dev/null
@@ -1,21 +0,0 @@
-CONFIG_SMP=y
-CONFIG_NR_CPUS=16
-CONFIG_PREEMPT_NONE=n
-CONFIG_PREEMPT_VOLUNTARY=n
-CONFIG_PREEMPT=y
-#CHECK#CONFIG_PREEMPT_RCU=y
-CONFIG_HZ_PERIODIC=n
-CONFIG_NO_HZ_IDLE=y
-CONFIG_NO_HZ_FULL=n
-CONFIG_RCU_FAST_NO_HZ=n
-CONFIG_RCU_TRACE=y
-CONFIG_HOTPLUG_CPU=n
-CONFIG_SUSPEND=n
-CONFIG_HIBERNATION=n
-CONFIG_RCU_FANOUT=3
-CONFIG_RCU_FANOUT_LEAF=2
-CONFIG_RCU_NOCB_CPU=y
-CONFIG_RCU_NOCB_CPU_ALL=y
-CONFIG_DEBUG_LOCK_ALLOC=n
-CONFIG_RCU_BOOST=n
-CONFIG_DEBUG_OBJECTS_RCU_HEAD=n
diff --git a/tools/testing/selftests/rcutorture/doc/TREE_RCU-kconfig.txt b/tools/testing/selftests/rcutorture/doc/TREE_RCU-kconfig.txt
index c5c29fb7438c..928fadaecc25 100644
--- a/tools/testing/selftests/rcutorture/doc/TREE_RCU-kconfig.txt
+++ b/tools/testing/selftests/rcutorture/doc/TREE_RCU-kconfig.txt
@@ -79,9 +79,5 @@ CONFIG_TASKS_RCU
 
 	Selected by CONFIG_RCU_TORTURE_TEST, so cannot disable.
 
-CONFIG_RCU_TRACE
-
-	Implied by CONFIG_RCU_TRACE for Tree RCU.
-
 
 boot parameters ignored: TBD
-- 
2.5.2