Added test cases for workqueue helpers

Signed-off-by: Imran Khan <[email protected]>

Author: imran-kn

tests/linux_kernel/helpers/test_workqueue.py

@@ -0,0 +1,170 @@
+# Copyright (c) 2022, Oracle and/or its affiliates.
+# SPDX-License-Identifier: LGPL-2.1-or-later
+
+from drgn.helpers.linux.cpumask import for_each_online_cpu
+from drgn.helpers.linux.percpu import per_cpu, per_cpu_ptr
+from drgn.helpers.linux.pid import for_each_task
+from drgn.helpers.linux.workqueue import (
+    find_worker_executing_work,
+    find_workqueue,
+    for_each_cpu_worker_pool,
+    for_each_pending_work,
+    for_each_pending_work_in_pool,
+    for_each_pending_work_of_pwq,
+    for_each_pending_work_on_cpu,
+    for_each_pool,
+    for_each_pool_worker,
+    for_each_pwq,
+    for_each_worker,
+    for_each_workqueue,
+    get_work_pool,
+    get_work_pwq,
+)
+from tests.linux_kernel import LinuxKernelTestCase, skip_unless_have_test_kmod
+
+
+def system_workqueue_names(prog):
+    # Pick some global workqueues that will always exist
+    return {
+        prog["system_wq"].name.string_(),
+        prog["system_highpri_wq"].name.string_(),
+        prog["system_long_wq"].name.string_(),
+        prog["system_unbound_wq"].name.string_(),
+        prog["system_freezable_wq"].name.string_(),
+    }
+
+
+class TestWorkqueue(LinuxKernelTestCase):
+    @classmethod
+    @skip_unless_have_test_kmod
+    def setUpClass(cls):
+        cls.test_wq = cls.prog["drgn_test_wq"]
+        cls.test_works = [cls.prog["drgn_test_works"][i].address_ for i in range(5)]
+        cls.test_work_0 = cls.prog["drgn_test_works"][0].address_of_()
+        cls.test_blocker_work = cls.prog["drgn_test_blocker_work"].address_of_()
+        cls.test_wq_sysfs = open(
+            "/sys/module/drgn_test/parameters/workqueue_test_trigger", "w+"
+        )
+        cls.test_wq_sysfs.write("1")
+        cls.test_wq_sysfs.flush()
+
+    @classmethod
+    @skip_unless_have_test_kmod
+    def tearDownClass(cls):
+        cls.test_wq_sysfs.write("0")
+        cls.test_wq_sysfs.close()
+
+    def test_for_each_workqueue(self):
+        # The found workqueue names should be a superset of the test names.
+        self.assertGreaterEqual(
+            {wq.name.string_() for wq in for_each_workqueue(self.prog)},
+            system_workqueue_names(self.prog),
+        )
+
+    def test_for_each_pool(self):
+        self.assertIn(
+            per_cpu(self.prog["cpu_worker_pools"], 0)[0].address_of_(),
+            for_each_pool(self.prog),
+        )
+
+    def test_for_each_worker(self):
+        kworkers = [
+            task.value_()
+            for task in for_each_task(self.prog)
+            if task.comm.string_().decode().startswith("kworker")
+        ]
+        self.assertEqual(
+            [worker.task.value_() for worker in for_each_worker(self.prog)].sort(),
+            kworkers.sort(),
+        )
+
+    def test_for_each_pool_worker(self):
+        test_pool = per_cpu(self.prog["cpu_worker_pools"], 0)[0].address_
+        kworkers = [
+            workers.value_()
+            for workers in for_each_worker(self.prog)
+            if workers.pool.value_() == test_pool
+        ]
+        pool_kworkers = [
+            workers.value_()
+            for workers in for_each_pool_worker(
+                per_cpu(self.prog["cpu_worker_pools"], 0)[0].address_of_()
+            )
+        ]
+        self.assertEqual(kworkers.sort(), pool_kworkers.sort())
+
+    def test_for_each_cpu_worker_pool(self):
+        cpu0_worker_pools = [
+            per_cpu(self.prog["cpu_worker_pools"], 0)[i].address_ for i in [0, 1]
+        ]
+        worker_pools = [
+            worker_pool.value_()
+            for worker_pool in for_each_cpu_worker_pool(self.prog, 0)
+        ]
+        self.assertEqual(worker_pools, cpu0_worker_pools)
+
+    def test_find_workqueue(self):
+        workqueue_names = system_workqueue_names(self.prog)
+        for name in workqueue_names:
+            workqueue = find_workqueue(self.prog, name)
+            self.assertEqual(name, workqueue.name.string_())
+
+    @skip_unless_have_test_kmod
+    def test_for_each_pwq(self):
+        # Since "drgn_test_wq" is a bound workqueue, list pwqs
+        # should contain only per-cpu pwqs i.e cpu_pwqs
+        pwqs = [pwq.value_() for pwq in for_each_pwq(self.test_wq)]
+        cpu_pwqs = [
+            per_cpu_ptr(self.test_wq.cpu_pwqs, cpu).value_()
+            for cpu in for_each_online_cpu(self.prog)
+        ]
+        self.assertEqual(pwqs.sort(), cpu_pwqs.sort())
+
+    @skip_unless_have_test_kmod
+    def test_for_each_pending_work(self):
+        all_works = [work.value_() for work in for_each_pending_work(self.prog)]
+        self.assertGreaterEqual(all_works, self.test_works)
+
+    @skip_unless_have_test_kmod
+    def test_for_each_pending_work_on_cpu(self):
+        all_works = [
+            work.value_() for work in for_each_pending_work_on_cpu(self.prog, 0)
+        ]
+        self.assertGreaterEqual(all_works, self.test_works)
+
+    @skip_unless_have_test_kmod
+    def test_for_each_pending_work_in_pool(self):
+        pool = per_cpu(self.prog["cpu_worker_pools"], 0)[0].address_of_()
+        all_works_in_pool = [
+            work.value_() for work in for_each_pending_work_in_pool(pool)
+        ]
+        self.assertGreaterEqual(all_works_in_pool, self.test_works)
+
+    @skip_unless_have_test_kmod
+    def test_for_each_pending_work_of_pwq(self):
+        cpu_pwqs_0 = per_cpu_ptr(self.test_wq.cpu_pwqs, 0)
+        all_works_of_pwq = [
+            work.value_() for work in for_each_pending_work_of_pwq(cpu_pwqs_0)
+        ]
+        self.assertEqual(all_works_of_pwq, self.test_works)
+
+    @skip_unless_have_test_kmod
+    def test_get_work_pwq(self):
+        cpu_pwqs_0 = per_cpu_ptr(self.test_wq.cpu_pwqs, 0)
+        cpu_pwqs_1 = per_cpu_ptr(self.test_wq.cpu_pwqs, 1)
+        pwq = get_work_pwq(self.test_work_0)
+        self.assertEqual(pwq, cpu_pwqs_0)
+        self.assertNotEqual(pwq, cpu_pwqs_1)
+
+    @skip_unless_have_test_kmod
+    def test_get_work_pool(self):
+        pool = get_work_pool(self.test_work_0)
+        pool_0 = per_cpu(self.prog["cpu_worker_pools"], 0)[0].address_of_()
+        pool_1 = per_cpu(self.prog["cpu_worker_pools"], 1)[0].address_of_()
+        self.assertEqual(pool, pool_0)
+        self.assertNotEqual(pool, pool_1)
+
+    @skip_unless_have_test_kmod
+    def test_find_worker_executing_work(self):
+        worker = find_worker_executing_work(self.test_blocker_work)
+        self.assertEqual(worker.current_work, self.test_blocker_work)

tests/linux_kernel/kmod/drgn_test.c

@@ -33,6 +33,8 @@
 #include <linux/slab.h>
 #include <linux/vmalloc.h>
 #include <linux/wait.h>
+#include <linux/workqueue.h>
+#include <linux/delay.h>
 #if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 20, 0)
 #define HAVE_XARRAY 1
 #include <linux/xarray.h>
@@ -1070,6 +1072,90 @@ static void drgn_test_waitq_exit(void)
 	}
 }
 
+// workqeue
+
+struct workqueue_struct *drgn_test_wq;
+struct work_struct drgn_test_works[5];
+struct work_struct drgn_test_blocker_work;
+unsigned long drgn_test_skip_worker_loop = 1;
+
+static int workqueue_set_test_trigger(const char *val,
+					const struct kernel_param *kp)
+{
+	unsigned long trigger;
+	int ret, i;
+
+	ret = kstrtoul(val, 0, &trigger);
+	if (ret)
+		return ret;
+
+	if (trigger) {
+		ret = queue_work_on(0, drgn_test_wq, &drgn_test_blocker_work);
+
+		for (i = 0; i < 5; i++)
+			ret = queue_work_on(0, drgn_test_wq, &drgn_test_works[i]);
+
+		if (!ret)
+			drgn_test_skip_worker_loop = 0;
+	} else
+		drgn_test_skip_worker_loop = 0;
+
+	return 0;
+}
+
+static const struct kernel_param_ops workqueue_test_ops = {
+	.set	= workqueue_set_test_trigger,
+};
+
+module_param_cb(workqueue_test_trigger, &workqueue_test_ops, &drgn_test_skip_worker_loop,
+		0644);
+
+static void drgn_test_work_func(struct work_struct *data)
+{
+	(void)data;
+	mdelay(5); //just busy loop for 5ms
+	return;
+}
+
+static void drgn_test_blocker_work_func(struct work_struct *data)
+{
+	(void)data;
+
+	/*
+	 * mdelay will keep busy looping so workqueue framework should
+	 * not fork new workers for involved pool.
+	 * module exit resets the loop variable and this in turn will complete
+	 * the function. Subsequent destroy_workqueue from exit will orderly
+	 * cleanup remaining works and destroy the test workqueue
+	 */
+	while(drgn_test_skip_worker_loop) {
+		mdelay(10);
+		cond_resched();
+	}
+}
+
+static int __init drgn_test_workqueue_init(void)
+{
+	int i;
+
+	drgn_test_wq = alloc_workqueue("drgn_test_wq", 0, 0);
+	if (!drgn_test_wq)
+		return -ENOMEM;
+
+	INIT_WORK(&drgn_test_blocker_work, drgn_test_blocker_work_func);
+
+	for (i = 0; i < 5; i++)
+		INIT_WORK(&drgn_test_works[i], drgn_test_work_func);
+
+        return 0;
+}
+
+static void drgn_test_workqueue_exit(void)
+{
+	drgn_test_skip_worker_loop = 0;
+	destroy_workqueue(drgn_test_wq);
+}
+
 // Dummy function symbol.
 int drgn_test_function(int x)
 {
@@ -1088,6 +1174,7 @@ static void drgn_test_exit(void)
 	drgn_test_xarray_exit();
 	drgn_test_waitq_exit();
 	drgn_test_idr_exit();
+	drgn_test_workqueue_exit();
 }
 
 static int __init drgn_test_init(void)
@@ -1126,6 +1213,9 @@ static int __init drgn_test_init(void)
 	if (ret)
 		goto out;
 	ret = drgn_test_idr_init();
+	if (ret)
+		goto out;
+	ret = drgn_test_workqueue_init();
 out:
 	if (ret)
 		drgn_test_exit();