Merge branch 'for-mingo' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into core/rcu

Pull RCU updates from Paul E. McKenney:

 * Documentation updates, including fixes to the design-level
   requirements documentation and a fixed version of the design-level
   data-structure documentation.  These fixes include removing
   cartoons and getting rid of the html/htmlx duplication.

 * Further improvements to the new-age expedited grace periods.

 * Miscellaneous fixes.

 * Torture-test changes, including a new rcuperf module for measuring
   RCU grace-period performance and scalability, which is useful for
   the expedited-grace-period changes.

Signed-off-by: Ingo Molnar <mingo@kernel.org>

tools/testing/selftests/rcutorture/bin/jitter.sh

@@ -0,0 +1,90 @@
+#!/bin/bash
+#
+# Alternate sleeping and spinning on randomly selected CPUs.  The purpose
+# of this script is to inflict random OS jitter on a concurrently running
+# test.
+#
+# Usage: jitter.sh me duration [ sleepmax [ spinmax ] ]
+#
+# me: Random-number-generator seed salt.
+# duration: Time to run in seconds.
+# sleepmax: Maximum microseconds to sleep, defaults to one second.
+# spinmax: Maximum microseconds to spin, defaults to one millisecond.
+#
+# 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 (C) IBM Corporation, 2016
+#
+# Authors: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
+
+me=$(($1 * 1000))
+duration=$2
+sleepmax=${3-1000000}
+spinmax=${4-1000}
+
+n=1
+
+starttime=`awk 'BEGIN { print systime(); }' < /dev/null`
+
+while :
+do
+	# Check for done.
+	t=`awk -v s=$starttime 'BEGIN { print systime() - s; }' < /dev/null`
+	if test "$t" -gt "$duration"
+	then
+		exit 0;
+	fi
+
+	# Set affinity to randomly selected CPU
+	cpus=`ls /sys/devices/system/cpu/*/online |
+		sed -e 's,/[^/]*$,,' -e 's/^[^0-9]*//' |
+		grep -v '^0*$'`
+	cpumask=`awk -v cpus="$cpus" -v me=$me -v n=$n 'BEGIN {
+		srand(n + me + systime());
+		ncpus = split(cpus, ca);
+		curcpu = ca[int(rand() * ncpus + 1)];
+		mask = lshift(1, curcpu);
+		if (mask + 0 <= 0)
+			mask = 1;
+		printf("%#x\n", mask);
+	}' < /dev/null`
+	n=$(($n+1))
+	if ! taskset -p $cpumask $$ > /dev/null 2>&1
+	then
+		echo taskset failure: '"taskset -p ' $cpumask $$ '"'
+		exit 1
+	fi
+
+	# Sleep a random duration
+	sleeptime=`awk -v me=$me -v n=$n -v sleepmax=$sleepmax 'BEGIN {
+		srand(n + me + systime());
+		printf("%06d", int(rand() * sleepmax));
+	}' < /dev/null`
+	n=$(($n+1))
+	sleep .$sleeptime
+
+	# Spin a random duration
+	limit=`awk -v me=$me -v n=$n -v spinmax=$spinmax 'BEGIN {
+		srand(n + me + systime());
+		printf("%06d", int(rand() * spinmax));
+	}' < /dev/null`
+	n=$(($n+1))
+	for i in {1..$limit}
+	do
+		echo > /dev/null
+	done
+done
+
+exit 1

tools/testing/selftests/rcutorture/bin/kvm-recheck-rcuperf-ftrace.sh

@@ -0,0 +1,121 @@
+#!/bin/bash
+#
+# Analyze a given results directory for rcuperf performance measurements,
+# looking for ftrace data.  Exits with 0 if data was found, analyzed, and
+# printed.  Intended to be invoked from kvm-recheck-rcuperf.sh after
+# argument checking.
+#
+# Usage: kvm-recheck-rcuperf-ftrace.sh resdir
+#
+# 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 (C) IBM Corporation, 2016
+#
+# Authors: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
+
+i="$1"
+. tools/testing/selftests/rcutorture/bin/functions.sh
+
+if test "`grep -c 'rcu_exp_grace_period.*start' < $i/console.log`" -lt 100
+then
+	exit 10
+fi
+
+sed -e 's/^\[[^]]*]//' < $i/console.log |
+grep 'us : rcu_exp_grace_period' |
+sed -e 's/us : / : /' |
+tr -d '\015' |
+awk '
+$8 == "start" {
+	if (starttask != "")
+		nlost++;
+	starttask = $1;
+	starttime = $3;
+	startseq = $7;
+}
+
+$8 == "end" {
+	if (starttask == $1 && startseq == $7) {
+		curgpdur = $3 - starttime;
+		gptimes[++n] = curgpdur;
+		gptaskcnt[starttask]++;
+		sum += curgpdur;
+		if (curgpdur > 1000)
+			print "Long GP " starttime "us to " $3 "us (" curgpdur "us)";
+		starttask = "";
+	} else {
+		# Lost a message or some such, reset.
+		starttask = "";
+		nlost++;
+	}
+}
+
+$8 == "done" {
+	piggybackcnt[$1]++;
+}
+
+END {
+	newNR = asort(gptimes);
+	if (newNR <= 0) {
+		print "No ftrace records found???"
+		exit 10;
+	}
+	pct50 = int(newNR * 50 / 100);
+	if (pct50 < 1)
+		pct50 = 1;
+	pct90 = int(newNR * 90 / 100);
+	if (pct90 < 1)
+		pct90 = 1;
+	pct99 = int(newNR * 99 / 100);
+	if (pct99 < 1)
+		pct99 = 1;
+	div = 10 ** int(log(gptimes[pct90]) / log(10) + .5) / 100;
+	print "Histogram bucket size: " div;
+	last = gptimes[1] - 10;
+	count = 0;
+	for (i = 1; i <= newNR; i++) {
+		current = div * int(gptimes[i] / div);
+		if (last == current) {
+			count++;
+		} else {
+			if (count > 0)
+				print last, count;
+			count = 1;
+			last = current;
+		}
+	}
+	if (count > 0)
+		print last, count;
+	print "Distribution of grace periods across tasks:";
+	for (i in gptaskcnt) {
+		print "\t" i, gptaskcnt[i];
+		nbatches += gptaskcnt[i];
+	}
+	ngps = nbatches;
+	print "Distribution of piggybacking across tasks:";
+	for (i in piggybackcnt) {
+		print "\t" i, piggybackcnt[i];
+		ngps += piggybackcnt[i];
+	}
+	print "Average grace-period duration: " sum / newNR " microseconds";
+	print "Minimum grace-period duration: " gptimes[1];
+	print "50th percentile grace-period duration: " gptimes[pct50];
+	print "90th percentile grace-period duration: " gptimes[pct90];
+	print "99th percentile grace-period duration: " gptimes[pct99];
+	print "Maximum grace-period duration: " gptimes[newNR];
+	print "Grace periods: " ngps + 0 " Batches: " nbatches + 0 " Ratio: " ngps / nbatches " Lost: " nlost + 0;
+	print "Computed from ftrace data.";
+}'
+exit 0

tools/testing/selftests/rcutorture/bin/kvm-recheck-rcuperf.sh

@@ -0,0 +1,96 @@
+#!/bin/bash
+#
+# Analyze a given results directory for rcuperf performance measurements.
+#
+# Usage: kvm-recheck-rcuperf.sh resdir
+#
+# 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 (C) IBM Corporation, 2016
+#
+# Authors: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
+
+i="$1"
+if test -d $i
+then
+	:
+else
+	echo Unreadable results directory: $i
+	exit 1
+fi
+PATH=`pwd`/tools/testing/selftests/rcutorture/bin:$PATH; export PATH
+. tools/testing/selftests/rcutorture/bin/functions.sh
+
+if kvm-recheck-rcuperf-ftrace.sh $i
+then
+	# ftrace data was successfully analyzed, call it good!
+	exit 0
+fi
+
+configfile=`echo $i | sed -e 's/^.*\///'`
+
+sed -e 's/^\[[^]]*]//' < $i/console.log |
+awk '
+/-perf: .* gps: .* batches:/ {
+	ngps = $9;
+	nbatches = $11;
+}
+
+/-perf: .*writer-duration/ {
+	gptimes[++n] = $5 / 1000.;
+	sum += $5 / 1000.;
+}
+
+END {
+	newNR = asort(gptimes);
+	if (newNR <= 0) {
+		print "No rcuperf records found???"
+		exit;
+	}
+	pct50 = int(newNR * 50 / 100);
+	if (pct50 < 1)
+		pct50 = 1;
+	pct90 = int(newNR * 90 / 100);
+	if (pct90 < 1)
+		pct90 = 1;
+	pct99 = int(newNR * 99 / 100);
+	if (pct99 < 1)
+		pct99 = 1;
+	div = 10 ** int(log(gptimes[pct90]) / log(10) + .5) / 100;
+	print "Histogram bucket size: " div;
+	last = gptimes[1] - 10;
+	count = 0;
+	for (i = 1; i <= newNR; i++) {
+		current = div * int(gptimes[i] / div);
+		if (last == current) {
+			count++;
+		} else {
+			if (count > 0)
+				print last, count;
+			count = 1;
+			last = current;
+		}
+	}
+	if (count > 0)
+		print last, count;
+	print "Average grace-period duration: " sum / newNR " microseconds";
+	print "Minimum grace-period duration: " gptimes[1];
+	print "50th percentile grace-period duration: " gptimes[pct50];
+	print "90th percentile grace-period duration: " gptimes[pct90];
+	print "99th percentile grace-period duration: " gptimes[pct99];
+	print "Maximum grace-period duration: " gptimes[newNR];
+	print "Grace periods: " ngps + 0 " Batches: " nbatches + 0 " Ratio: " ngps / nbatches;
+	print "Computed from rcuperf printk output.";
+}'

tools/testing/selftests/rcutorture/bin/kvm-recheck.sh

@@ -48,7 +48,10 @@ do
 				cat $i/Make.oldconfig.err
 			fi
 			parse-build.sh $i/Make.out $configfile
-			parse-torture.sh $i/console.log $configfile
+			if test "$TORTURE_SUITE" != rcuperf
+			then
+				parse-torture.sh $i/console.log $configfile
+			fi
 			parse-console.sh $i/console.log $configfile
 			if test -r $i/Warnings
 			then

tools/testing/selftests/rcutorture/bin/kvm-test-1-run.sh

@@ -6,7 +6,7 @@
 # Execute this in the source tree.  Do not run it as a background task
 # because qemu does not seem to like that much.
 #
-# Usage: kvm-test-1-run.sh config builddir resdir minutes qemu-args boot_args
+# Usage: kvm-test-1-run.sh config builddir resdir seconds qemu-args boot_args
 #
 # qemu-args defaults to "-enable-kvm -soundhw pcspk -nographic", along with
 #			arguments specifying the number of CPUs and other
@@ -91,25 +91,33 @@ fi
 # CONFIG_PCMCIA=n
 # CONFIG_CARDBUS=n
 # CONFIG_YENTA=n
-if kvm-build.sh $config_template $builddir $T
+base_resdir=`echo $resdir | sed -e 's/\.[0-9]\+$//'`
+if test "$base_resdir" != "$resdir" -a -f $base_resdir/bzImage -a -f $base_resdir/vmlinux
 then
+	# Rerunning previous test, so use that test's kernel.
+	QEMU="`identify_qemu $base_resdir/vmlinux`"
+	KERNEL=$base_resdir/bzImage
+	ln -s $base_resdir/Make*.out $resdir  # for kvm-recheck.sh
+	ln -s $base_resdir/.config $resdir  # for kvm-recheck.sh
+elif kvm-build.sh $config_template $builddir $T
+then
+	# Had to build a kernel for this test.
 	QEMU="`identify_qemu $builddir/vmlinux`"
 	BOOT_IMAGE="`identify_boot_image $QEMU`"
 	cp $builddir/Make*.out $resdir
+	cp $builddir/vmlinux $resdir
 	cp $builddir/.config $resdir
 	if test -n "$BOOT_IMAGE"
 	then
 		cp $builddir/$BOOT_IMAGE $resdir
+		KERNEL=$resdir/bzImage
 	else
 		echo No identifiable boot image, not running KVM, see $resdir.
 		echo Do the torture scripts know about your architecture?
 	fi
 	parse-build.sh $resdir/Make.out $title
-	if test -f $builddir.wait
-	then
-		mv $builddir.wait $builddir.ready
-	fi
 else
+	# Build failed.
 	cp $builddir/Make*.out $resdir
 	cp $builddir/.config $resdir || :
 	echo Build failed, not running KVM, see $resdir.
@@ -119,12 +127,15 @@ else
 	fi
 	exit 1
 fi
+if test -f $builddir.wait
+then
+	mv $builddir.wait $builddir.ready
+fi
 while test -f $builddir.ready
 do
 	sleep 1
 done
-minutes=$4
-seconds=$(($minutes * 60))
+seconds=$4
 qemu_args=$5
 boot_args=$6
 
@@ -167,15 +178,26 @@ then
 	exit 0
 fi
 echo "NOTE: $QEMU either did not run or was interactive" > $resdir/console.log
-echo $QEMU $qemu_args -m 512 -kernel $resdir/bzImage -append \"$qemu_append $boot_args\" > $resdir/qemu-cmd
-( $QEMU $qemu_args -m 512 -kernel $resdir/bzImage -append "$qemu_append $boot_args"; echo $? > $resdir/qemu-retval ) &
-qemu_pid=$!
+echo $QEMU $qemu_args -m 512 -kernel $KERNEL -append \"$qemu_append $boot_args\" > $resdir/qemu-cmd
+( $QEMU $qemu_args -m 512 -kernel $KERNEL -append "$qemu_append $boot_args"& echo $! > $resdir/qemu_pid; wait `cat  $resdir/qemu_pid`; echo $? > $resdir/qemu-retval ) &
 commandcompleted=0
-echo Monitoring qemu job at pid $qemu_pid
+sleep 10 # Give qemu's pid a chance to reach the file
+if test -s "$resdir/qemu_pid"
+then
+	qemu_pid=`cat "$resdir/qemu_pid"`
+	echo Monitoring qemu job at pid $qemu_pid
+else
+	qemu_pid=""
+	echo Monitoring qemu job at yet-as-unknown pid
+fi
 while :
 do
+	if test -z "$qemu_pid" -a -s "$resdir/qemu_pid"
+	then
+		qemu_pid=`cat "$resdir/qemu_pid"`
+	fi
 	kruntime=`awk 'BEGIN { print systime() - '"$kstarttime"' }' < /dev/null`
-	if kill -0 $qemu_pid > /dev/null 2>&1
+	if test -z "$qemu_pid" || kill -0 "$qemu_pid" > /dev/null 2>&1
 	then
 		if test $kruntime -ge $seconds
 		then
@@ -195,12 +217,16 @@ do
 				ps -fp $killpid >> $resdir/Warnings 2>&1
 			fi
 		else
-			echo ' ---' `date`: Kernel done
+			echo ' ---' `date`: "Kernel done"
 		fi
 		break
 	fi
 done
-if test $commandcompleted -eq 0
+if test -z "$qemu_pid" -a -s "$resdir/qemu_pid"
+then
+	qemu_pid=`cat "$resdir/qemu_pid"`
+fi
+if test $commandcompleted -eq 0 -a -n "$qemu_pid"
 then
 	echo Grace period for qemu job at pid $qemu_pid
 	while :
@@ -220,6 +246,9 @@ then
 		fi
 		sleep 1
 	done
+elif test -z "$qemu_pid"
+then
+	echo Unknown PID, cannot kill qemu command
 fi
 
 parse-torture.sh $resdir/console.log $title

tools/testing/selftests/rcutorture/bin/kvm.sh

@@ -34,7 +34,7 @@ T=/tmp/kvm.sh.$$
 trap 'rm -rf $T' 0
 mkdir $T
 
-dur=30
+dur=$((30*60))
 dryrun=""
 KVM="`pwd`/tools/testing/selftests/rcutorture"; export KVM
 PATH=${KVM}/bin:$PATH; export PATH
@@ -48,6 +48,7 @@ resdir=""
 configs=""
 cpus=0
 ds=`date +%Y.%m.%d-%H:%M:%S`
+jitter=0
 
 . functions.sh
 
@@ -63,6 +64,7 @@ usage () {
 	echo "       --dryrun sched|script"
 	echo "       --duration minutes"
 	echo "       --interactive"
+	echo "       --jitter N [ maxsleep (us) [ maxspin (us) ] ]"
 	echo "       --kmake-arg kernel-make-arguments"
 	echo "       --mac nn:nn:nn:nn:nn:nn"
 	echo "       --no-initrd"
@@ -116,12 +118,17 @@ do
 		;;
 	--duration)
 		checkarg --duration "(minutes)" $# "$2" '^[0-9]*$' '^error'
-		dur=$2
+		dur=$(($2*60))
 		shift
 		;;
 	--interactive)
 		TORTURE_QEMU_INTERACTIVE=1; export TORTURE_QEMU_INTERACTIVE
 		;;
+	--jitter)
+		checkarg --jitter "(# threads [ sleep [ spin ] ])" $# "$2" '^-\{,1\}[0-9]\+\( \+[0-9]\+\)\{,2\} *$' '^error$'
+		jitter="$2"
+		shift
+		;;
 	--kmake-arg)
 		checkarg --kmake-arg "(kernel make arguments)" $# "$2" '.*' '^error$'
 		TORTURE_KMAKE_ARG="$2"
@@ -156,7 +163,7 @@ do
 		shift
 		;;
 	--torture)
-		checkarg --torture "(suite name)" "$#" "$2" '^\(lock\|rcu\)$' '^--'
+		checkarg --torture "(suite name)" "$#" "$2" '^\(lock\|rcu\|rcuperf\)$' '^--'
 		TORTURE_SUITE=$2
 		shift
 		;;
@@ -299,6 +306,7 @@ awk < $T/cfgcpu.pack \
 	-v CONFIGDIR="$CONFIGFRAG/" \
 	-v KVM="$KVM" \
 	-v ncpus=$cpus \
+	-v jitter="$jitter" \
 	-v rd=$resdir/$ds/ \
 	-v dur=$dur \
 	-v TORTURE_QEMU_ARG="$TORTURE_QEMU_ARG" \
@@ -359,6 +367,16 @@ function dump(first, pastlast, batchnum)
 		print "\techo ----", cfr[j], cpusr[j] ovf ": Starting kernel. `date` >> " rd "/log";
 		print "fi"
 	}
+	njitter = 0;
+	split(jitter, ja);
+	if (ja[1] == -1 && ncpus == 0)
+		njitter = 1;
+	else if (ja[1] == -1)
+		njitter = ncpus;
+	else
+		njitter = ja[1];
+	for (j = 0; j < njitter; j++)
+		print "jitter.sh " j " " dur " " ja[2] " " ja[3] "&"
 	print "wait"
 	print "if test -z \"$TORTURE_BUILDONLY\""
 	print "then"

tools/testing/selftests/rcutorture/configs/rcu/TREE04

@@ -14,7 +14,7 @@ CONFIG_HOTPLUG_CPU=n
 CONFIG_SUSPEND=n
 CONFIG_HIBERNATION=n
 CONFIG_RCU_FANOUT=4
-CONFIG_RCU_FANOUT_LEAF=4
+CONFIG_RCU_FANOUT_LEAF=3
 CONFIG_RCU_NOCB_CPU=n
 CONFIG_DEBUG_LOCK_ALLOC=n
 CONFIG_DEBUG_OBJECTS_RCU_HEAD=n

tools/testing/selftests/rcutorture/configs/rcu/TREE04.boot

@@ -1 +1 @@
-rcutorture.torture_type=rcu_bh
+rcutorture.torture_type=rcu_bh rcutree.rcu_fanout_leaf=4

tools/testing/selftests/rcutorture/configs/rcuperf/CFLIST

@@ -0,0 +1 @@
+TREE

tools/testing/selftests/rcutorture/configs/rcuperf/CFcommon

@@ -0,0 +1,2 @@
+CONFIG_RCU_PERF_TEST=y
+CONFIG_PRINTK_TIME=y

tools/testing/selftests/rcutorture/configs/rcuperf/TREE

@@ -0,0 +1,20 @@
+CONFIG_SMP=y
+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=n
+CONFIG_HOTPLUG_CPU=n
+CONFIG_SUSPEND=n
+CONFIG_HIBERNATION=n
+CONFIG_RCU_NOCB_CPU=n
+CONFIG_DEBUG_LOCK_ALLOC=n
+CONFIG_PROVE_LOCKING=n
+CONFIG_RCU_BOOST=n
+CONFIG_DEBUG_OBJECTS_RCU_HEAD=n
+CONFIG_RCU_EXPERT=y
+CONFIG_RCU_TRACE=y

tools/testing/selftests/rcutorture/configs/rcuperf/TREE54

@@ -0,0 +1,23 @@
+CONFIG_SMP=y
+CONFIG_NR_CPUS=54
+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=n
+CONFIG_HOTPLUG_CPU=n
+CONFIG_SUSPEND=n
+CONFIG_HIBERNATION=n
+CONFIG_RCU_FANOUT=3
+CONFIG_RCU_FANOUT_LEAF=2
+CONFIG_RCU_NOCB_CPU=n
+CONFIG_DEBUG_LOCK_ALLOC=n
+CONFIG_PROVE_LOCKING=n
+CONFIG_RCU_BOOST=n
+CONFIG_DEBUG_OBJECTS_RCU_HEAD=n
+CONFIG_RCU_EXPERT=y
+CONFIG_RCU_TRACE=y

tools/testing/selftests/rcutorture/configs/rcuperf/ver_functions.sh

@@ -0,0 +1,52 @@
+#!/bin/bash
+#
+# Torture-suite-dependent shell functions for the rest of the scripts.
+#
+# 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 (C) IBM Corporation, 2015
+#
+# Authors: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
+
+# rcuperf_param_nreaders bootparam-string
+#
+# Adds nreaders rcuperf module parameter if not already specified.
+rcuperf_param_nreaders () {
+	if ! echo "$1" | grep -q "rcuperf.nreaders"
+	then
+		echo rcuperf.nreaders=-1
+	fi
+}
+
+# rcuperf_param_nwriters bootparam-string
+#
+# Adds nwriters rcuperf module parameter if not already specified.
+rcuperf_param_nwriters () {
+	if ! echo "$1" | grep -q "rcuperf.nwriters"
+	then
+		echo rcuperf.nwriters=-1
+	fi
+}
+
+# per_version_boot_params bootparam-string config-file seconds
+#
+# Adds per-version torture-module parameters to kernels supporting them.
+per_version_boot_params () {
+	echo $1 `rcuperf_param_nreaders "$1"` \
+		`rcuperf_param_nwriters "$1"` \
+		rcuperf.perf_runnable=1 \
+		rcuperf.shutdown=1 \
+		rcuperf.verbose=1
+}