rcutorture: Default grace period to three minutes, allow override

The default test grace period of two minutes is insufficient in some
cases and excessive in others.  This commit therefore increases the
default to three minutes, but also adds a --shutdown-grace parameter
to allow the default to be overridden.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>

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

@@ -38,8 +38,6 @@
 #
 # Authors: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
 
-grace=120
-
 T=/tmp/kvm-test-1-run.sh.$$
 trap 'rm -rf $T' 0
 touch $T
@@ -214,7 +212,7 @@ then
 		else
 			break
 		fi
-		if test $kruntime -ge $((seconds + grace))
+		if test $kruntime -ge $((seconds + $TORTURE_SHUTDOWN_GRACE))
 		then
 			echo "!!! PID $qemu_pid hung at $kruntime vs. $seconds seconds" >> $resdir/Warnings 2>&1
 			kill -KILL $qemu_pid

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

@@ -42,6 +42,7 @@ TORTURE_DEFCONFIG=defconfig
 TORTURE_BOOT_IMAGE=""
 TORTURE_INITRD="$KVM/initrd"; export TORTURE_INITRD
 TORTURE_KMAKE_ARG=""
+TORTURE_SHUTDOWN_GRACE=180
 TORTURE_SUITE=rcu
 resdir=""
 configs=""
@@ -149,6 +150,11 @@ do
 		resdir=$2
 		shift
 		;;
+	--shutdown-grace)
+		checkarg --shutdown-grace "(seconds)" "$#" "$2" '^[0-9]*$' '^error'
+		TORTURE_SHUTDOWN_GRACE=$2
+		shift
+		;;
 	--torture)
 		checkarg --torture "(suite name)" "$#" "$2" '^\(lock\|rcu\)$' '^--'
 		TORTURE_SUITE=$2
@@ -266,6 +272,7 @@ TORTURE_KMAKE_ARG="$TORTURE_KMAKE_ARG"; export TORTURE_KMAKE_ARG
 TORTURE_QEMU_CMD="$TORTURE_QEMU_CMD"; export TORTURE_QEMU_CMD
 TORTURE_QEMU_INTERACTIVE="$TORTURE_QEMU_INTERACTIVE"; export TORTURE_QEMU_INTERACTIVE
 TORTURE_QEMU_MAC="$TORTURE_QEMU_MAC"; export TORTURE_QEMU_MAC
+TORTURE_SHUTDOWN_GRACE="$TORTURE_SHUTDOWN_GRACE"; export TORTURE_SHUTDOWN_GRACE
 TORTURE_SUITE="$TORTURE_SUITE"; export TORTURE_SUITE
 if ! test -e $resdir
 then