torture: Allow "CFLIST" to specify default list of scenarios

On a large system, it can be convenient to tell rcutorture to run
several instances of the default scenarios.  Currently, this requires
explicitly listing them, for example, "--configs '2*SRCU-N 2*SRCU-P...'".
Although this works, it is rather inconvenient.

This commit therefore allows "CFLIST" to be specified to indicate the
default list of scenarios called out in the relevant CFLIST file, for
example, for RCU, tools/testing/selftests/rcutorture/configs/rcu/CFLIST.
In addition, multipliers may be used to run multiple instances of all
the scenarios.  For example, on a 256-CPU system, "--configs '3*CFLIST'"
would run three instances of each scenario concurrently with one CPU
left over.  Thus "--configs '3*CFLIST TINY01'" would exactly consume all
256 CPUs, which makes rcutorture's jitter feature more effective.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

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

@@ -198,9 +198,10 @@ fi
 
 CONFIGFRAG=${KVM}/configs/${TORTURE_SUITE}; export CONFIGFRAG
 
+defaultconfigs="`tr '\012' ' ' < $CONFIGFRAG/CFLIST`"
 if test -z "$configs"
 then
-	configs="`cat $CONFIGFRAG/CFLIST`"
+	configs=$defaultconfigs
 fi
 
 if test -z "$resdir"
@@ -209,7 +210,7 @@ then
 fi
 
 # Create a file of test-name/#cpus pairs, sorted by decreasing #cpus.
-touch $T/cfgcpu
+configs_derep=
 for CF in $configs
 do
 	case $CF in
@@ -222,15 +223,21 @@ do
 		CF1=$CF
 		;;
 	esac
+	for ((cur_rep=0;cur_rep<$config_reps;cur_rep++))
+	do
+		configs_derep="$configs_derep $CF1"
+	done
+done
+touch $T/cfgcpu
+configs_derep="`echo $configs_derep | sed -e "s/\<CFLIST\>/$defaultconfigs/g"`"
+for CF1 in $configs_derep
+do
 	if test -f "$CONFIGFRAG/$CF1"
 	then
 		cpu_count=`configNR_CPUS.sh $CONFIGFRAG/$CF1`
 		cpu_count=`configfrag_boot_cpus "$TORTURE_BOOTARGS" "$CONFIGFRAG/$CF1" "$cpu_count"`
 		cpu_count=`configfrag_boot_maxcpus "$TORTURE_BOOTARGS" "$CONFIGFRAG/$CF1" "$cpu_count"`
-		for ((cur_rep=0;cur_rep<$config_reps;cur_rep++))
-		do
-			echo $CF1 $cpu_count >> $T/cfgcpu
-		done
+		echo $CF1 $cpu_count >> $T/cfgcpu
 	else
 		echo "The --configs file $CF1 does not exist, terminating."
 		exit 1