[PATCH] block: fix fio jobs for 027 and add cgroup support

[Dennis Zhou <dennis@kernel.org>]

Previously, the test was broken as "$fio_jobs" was considered as a
string instead of additional parameters. This is fixed here.

Second, there was an issue with earlier kernels when request lists
existed such that request_queues were never being cleaned up because
non-root blkgs took a reference on the queue. However, blkgs were being
cleaned up after the last reference to the request_queue was put back.
This creates a blktest cgroup for the fio jobs to utilize and should be
useful for catching this scenario in the future.

Signed-off-by: Dennis Zhou <dennis@kernel.org>
---
 tests/block/027 | 17 ++++++++++++++---
 1 file changed, 14 insertions(+), 3 deletions(-)

diff --git a/tests/block/027 b/tests/block/027
index b480016..36e88b4 100755
--- a/tests/block/027
+++ b/tests/block/027
@@ -26,6 +26,13 @@ scsi_debug_stress_remove() {
 		return
 	fi
 
+	_init_cgroup2
+
+	# setup cgroups
+	echo "+io" > "/sys/fs/cgroup/cgroup.subtree_control"
+	echo "+io" > "$CGROUP2_DIR/cgroup.subtree_control"
+	mkdir "$CGROUP2_DIR/fast"
+
 	# set higher aio limit
 	echo 524288 > /proc/sys/fs/aio-max-nr
 
@@ -45,13 +52,13 @@ scsi_debug_stress_remove() {
 		((cnt++))
 	done
 
-	local num_jobs=4 runtime=21
+	local num_jobs=4 runtime=12
 	fio --rw=randread --size=128G --direct=1 --ioengine=libaio \
 		--iodepth=2048 --numjobs=$num_jobs --bs=4k \
 		--group_reporting=1 --group_reporting=1 --runtime=$runtime \
-		--loops=10000 "$fio_jobs" > "$FULL" 2>&1 &
+		--loops=10000 --cgroup=blktests/fast $fio_jobs > "$FULL" 2>&1 &
 
-	sleep 7
+	sleep 6
 	local device_path
 	for dev in "${SCSI_DEBUG_DEVICES[@]}"; do
 		# shutdown devices in progress
@@ -61,6 +68,10 @@ scsi_debug_stress_remove() {
 
 	wait
 
+	sleep 10
+
+	_exit_cgroup2
+
 	_exit_scsi_debug
 }
 
-- 
2.17.1