torture: Make kvm-series.sh give build numbers and totals

The kvm-series.sh script can easily be convinced to do on the order
of 1,000 builds, so some sort of progress indicator would be helpful.
This commit therefore updates the "Starting" output lines to read
as in the following example, adding the ("2 of 4"):

Starting TREE01/1.7e0ad1b49057 (2 of 4) at Sat Nov 8 10:08:21 PM PST 2025

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>

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

@@ -32,6 +32,7 @@ then
 	echo "$0: Repetition ('*') not allowed in config list."
 	exit 1
 fi
+config_list_len="`echo ${config_list} | wc -w | awk '{ print $1; }'`"
 
 commit_list="${2}"
 if test -z "${commit_list}"
@@ -47,6 +48,7 @@ then
 	exit 2
 fi
 sha1_list=`cat $T/commits`
+sha1_list_len="`echo ${sha1_list} | wc -w | awk '{ print $1; }'`"
 
 shift
 shift
@@ -80,6 +82,8 @@ echo " --- Results directory: " $ds | tee -a $T/log
 # turning preemption on and off.  Defer actual runs in order to run
 # lots of them concurrently on large systems.
 touch $T/torunlist
+n2build="$((config_list_len*sha1_list_len))"
+nbuilt=0
 for config in ${config_list}
 do
 	sha_n=0
@@ -87,7 +91,7 @@ do
 	do
 		sha1=${sha_n}.${sha} # Enable "sort -k1nr" to list commits in order.
 		echo
-		echo Starting ${config}/${sha1} at `date` | tee -a $T/log
+		echo Starting ${config}/${sha1} "($((nbuilt+1)) of ${n2build})" at `date` | tee -a $T/log
 		git checkout --detach "${sha}"
 		tools/testing/selftests/rcutorture/bin/kvm.sh --configs "$config" --datestamp "$ds/${config}/${sha1}" --duration 1 --build-only --trust-make "$@"
 		curret=$?
@@ -115,6 +119,7 @@ do
 			ret=${curret}
 		fi
 		sha_n=$((sha_n+1))
+		nbuilt=$((nbuilt+1))
 	done
 done