Add I/O priority

Signed-off-by: utam0k <k0ma@utam0k.jp>

tests/integration/ioprio.bats

@@ -0,0 +1,30 @@
+#!/usr/bin/env bats
+
+load helpers
+
+function setup() {
+	setup_debian
+}
+
+function teardown() {
+	teardown_bundle
+}
+
+@test "ioprio_set is applied to process group" {
+	# Create a container with a specific I/O priority.
+	update_config '.process.ioPriority = {"class": "IOPRIO_CLASS_BE", "priority": 4}'
+
+	runc run -d --console-socket "$CONSOLE_SOCKET" test_ioprio
+	[ "$status" -eq 0 ]
+
+	# Check the init process.
+	runc exec test_ioprio ionice -p 1
+	[ "$status" -eq 0 ]
+	[[ "$output" = *'best-effort: prio 4'* ]]
+
+	# Check the process made from the exec command.
+	runc exec test_ioprio ionice
+	[ "$status" -eq 0 ]
+
+	[[ "$output" = *'best-effort: prio 4'* ]]
+}