[PATCH blktests 2/2] Add a test that triggers blk_mq_update_nr_hw_queues()

[Bart Van Assche <bvanassche@xxxxxxx>]

Signed-off-by: Bart Van Assche <bvanassche@xxxxxxx>
---
 tests/block/029     | 63 +++++++++++++++++++++++++++++++++++++++++++++
 tests/block/029.out |  1 +
 2 files changed, 64 insertions(+)
 create mode 100755 tests/block/029
 create mode 100644 tests/block/029.out

diff --git a/tests/block/029 b/tests/block/029
new file mode 100755
index 000000000000..1999168603c1
--- /dev/null
+++ b/tests/block/029
@@ -0,0 +1,63 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (C) 2019 Google Inc.
+#
+# Trigger blk_mq_update_nr_hw_queues().
+
+. tests/block/rc
+. common/null_blk
+
+DESCRIPTION="trigger blk_mq_update_nr_hw_queues()"
+QUICK=1
+
+requires() {
+	_have_null_blk
+}
+
+# Configure one null_blk instance.
+configure_null_blk() {
+	(
+		cd /sys/kernel/config/nullb || return $?
+		(
+			mkdir -p nullb0 &&
+				cd nullb0 &&
+				echo 0 > completion_nsec &&
+				echo 512 > blocksize &&
+				echo 16 > size &&
+				echo 1 > memory_backed &&
+				echo 1 > power
+		)
+	) &&
+	ls -l /dev/nullb* &>>"$FULL"
+}
+
+modify_nr_hw_queues() {
+	local deadline num_cpus
+
+	deadline=$(($(_uptime_s) + TIMEOUT))
+	num_cpus=$(find /sys/devices/system/cpu -maxdepth 1 -name 'cpu[0-9]*' |
+			   wc -l)
+	while [ "$(_uptime_s)" -lt "$deadline" ]; do
+		sleep .1
+		echo 1 > /sys/kernel/config/nullb/nullb0/submit_queues
+		sleep .1
+		echo "$num_cpus" > /sys/kernel/config/nullb/nullb0/submit_queues
+	done
+}
+
+test() {
+	: "${TIMEOUT:=30}"
+	_init_null_blk nr_devices=0 queue_mode=2 &&
+	configure_null_blk
+	modify_nr_hw_queues &
+	fio --rw=randwrite --bs=4K --loops=$((10**6)) \
+		--iodepth=64 --group_reporting --sync=1 --direct=1 \
+		--ioengine=libaio --filename="/dev/nullb0" \
+		--runtime="${TIMEOUT}" --name=nullb0 \
+		--output="${RESULTS_DIR}/block/fio-output-029.txt" \
+		>>"$FULL"
+	wait
+	rmdir /sys/kernel/config/nullb/nullb0
+	_exit_null_blk
+	echo Passed
+}
diff --git a/tests/block/029.out b/tests/block/029.out
new file mode 100644
index 000000000000..863339fb8ced
--- /dev/null
+++ b/tests/block/029.out
@@ -0,0 +1 @@
+Passed
-- 
2.23.0.866.gb869b98d4c-goog