[LTP] [PATCH 1/4] controllers/memcg: update stress test to work under cgroup2

[Luke Nowakowski-Krijger]

Update tests to be able to work when memory controller is mounted under
cgroup2 hierarchy.

Remove redundant mounts so that it mounts once for both tests to keep
the logic a bit simpler.

Signed-off-by: Luke Nowakowski-Krijger <luke.nowakowskikrijger@canonical.com>
---
 .../memcg/stress/memcg_stress_test.sh         | 73 ++++++++++++++-----
 1 file changed, 56 insertions(+), 17 deletions(-)

diff --git a/testcases/kernel/controllers/memcg/stress/memcg_stress_test.sh b/testcases/kernel/controllers/memcg/stress/memcg_stress_test.sh
index c43d72116..ba7c8f386 100755
--- a/testcases/kernel/controllers/memcg/stress/memcg_stress_test.sh
+++ b/testcases/kernel/controllers/memcg/stress/memcg_stress_test.sh
@@ -21,12 +21,62 @@ TST_TIMEOUT=2100
 
 . cgroup_lib.sh
 
+setup_cgroupv2()
+{
+	mount_point=$(grep -w cgroup2 /proc/mounts | cut -f 2 | cut -d " " -f2)
+	if ! grep -q memory "$mount_point"/cgroup.controllers; then
+		tst_res TINFO "memory controller not supported on cgroup v2."
+		return
+	fi
+
+	task_list="cgroup.procs"
+	cgroup_v="v2"
+}
+
+setup_cgroupv1()
+{
+	exist=$(grep -w memory /proc/cgroups | cut -f1);
+	if [ "$exist" = "" ]; then
+		tst_brk TCONF NULL "memory controller not supported"
+	fi
+
+	mount_point=$(grep -w memory /proc/mounts | cut -f 2 | cut -d " " -f2)
+	if [ "$mount_point" = "" ]; then
+		cgroup_mounted=0
+		mount_point="/dev/memcg"
+	fi
+
+	if [ "$cgroup_mounted" -eq "0" ]; then
+		ROD mkdir -p $mount_point
+		ROD mount -t cgroup -o memory none $mount_point
+	fi
+
+	task_list="tasks"
+	cgroup_v="v1"
+}
+
 setup()
 {
 	if ! is_cgroup_subsystem_available_and_enabled "memory"; then
 		tst_brk TCONF "Either kernel does not support Memory Resource Controller or feature not enabled"
 	fi
 
+	if tst_kvcmp -lt "2.6.30"; then
+		tst_brk TBROK "Test should be run with kernel 2.6.30 or newer"
+	fi
+
+	cgroup_mounted=1
+
+	if grep -q cgroup2 /proc/mounts; then
+		setup_cgroupv2
+	fi
+
+	if [ -z "$cgroup_v" ]; then
+		setup_cgroupv1
+	fi
+
+	tst_res TINFO "test starts with cgroup $cgroup_v"
+
 	echo 3 > /proc/sys/vm/drop_caches
 	sleep 2
 	local mem_free=`cat /proc/meminfo | grep MemFree | awk '{ print $2 }'`
@@ -43,20 +93,12 @@ setup()
 
 cleanup()
 {
-	if [ -e /dev/memcg ]; then
-		EXPECT_PASS umount /dev/memcg
-		EXPECT_PASS rmdir /dev/memcg
+	if [ $cgroup_mounted -eq "0" ]; then
+		EXPECT_PASS umount $mount_point
+		EXPECT_PASS rmdir $mount_point
 	fi
 }
 
-do_mount()
-{
-	cleanup
-
-	EXPECT_PASS mkdir /dev/memcg
-	EXPECT_PASS mount -t cgroup -omemory memcg /dev/memcg
-}
-
 # $1 Number of cgroups
 # $2 Allocated MB memory in one process
 # $3 The interval to touch memory in a process
@@ -71,13 +113,11 @@ run_stress()
 
 	tst_res TINFO "Testing $cgroups cgroups, using $mem_size MB, interval $interval"
 
-	do_mount
-
 	tst_res TINFO "Starting cgroups"
 	for i in $(seq 0 $(($cgroups-1))); do
-		mkdir /dev/memcg/$i 2> /dev/null
+		mkdir "$mount_point/$i" 2> /dev/null
 		memcg_process_stress $mem_size $interval &
-		echo $! > /dev/memcg/$i/tasks
+		echo $! > "$mount_point/$i/$task_list"
 		pids="$pids $!"
 	done
 
@@ -93,12 +133,11 @@ run_stress()
 	for pid in $pids; do
 		kill -KILL $pid 2> /dev/null
 		wait $pid 2> /dev/null
-		rmdir /dev/memcg/$i 2> /dev/null
+		rmdir "$mount_point/$i" 2> /dev/null
 		i=$((i+1))
 	done
 
 	tst_res TPASS "Test passed"
-	cleanup
 }
 
 test1()
-- 
2.32.0