Re: [PATCH 2/2] rcu-tasks: add RCU-tasks self tests
From: Paul E. McKenney
Date: Mon Dec 21 2020 - 12:19:09 EST
On Mon, Dec 21, 2020 at 04:38:09PM +0100, Uladzislau Rezki wrote:
> On Wed, Dec 16, 2020 at 03:29:55PM -0800, Paul E. McKenney wrote:
> > On Wed, Dec 16, 2020 at 04:49:59PM +0100, Uladzislau Rezki wrote:
[ . . . ]
> > > 2.20.1
> >
> > Again, much improved!
> >
> See below the v3 version. I hope i fixed all comments :)
>
> >From 06f7adfd84cbb1994d0e2693ee9dcdfd272a9bd0 Mon Sep 17 00:00:00 2001
> From: "Uladzislau Rezki (Sony)" <urezki@xxxxxxxxx>
> Date: Wed, 9 Dec 2020 21:27:32 +0100
> Subject: [PATCH v3 1/1] rcu-tasks: Add RCU-tasks self tests
>
> This commit adds self tests for early-boot use of RCU-tasks grace periods.
> It tests all three variants (Rude, Tasks, and Tasks Trace) and covers
> both synchronous (e.g., synchronize_rcu_tasks()) and asynchronous (e.g.,
> call_rcu_tasks()) grace-period APIs.
>
> Self-tests are run only in kernels built with CONFIG_PROVE_RCU=y.
>
> Signed-off-by: Uladzislau Rezki (Sony) <urezki@xxxxxxxxx>
Much better!
I pulled this in, but made one small additional change. Please let me
know if this is problematic.
Thanx, Paul
------------------------------------------------------------------------
commit 93372198b5c9efdfd288aa3b3ee41c1f90866886
Author: Uladzislau Rezki (Sony) <urezki@xxxxxxxxx>
Date: Wed Dec 9 21:27:32 2020 +0100
rcu-tasks: Add RCU-tasks self tests
This commit adds self tests for early-boot use of RCU-tasks grace periods.
It tests all three variants (Rude, Tasks, and Tasks Trace) and covers
both synchronous (e.g., synchronize_rcu_tasks()) and asynchronous (e.g.,
call_rcu_tasks()) grace-period APIs.
Self-tests are run only in kernels built with CONFIG_PROVE_RCU=y.
Signed-off-by: Uladzislau Rezki (Sony) <urezki@xxxxxxxxx>
Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxx>
diff --git a/kernel/rcu/tasks.h b/kernel/rcu/tasks.h
index 3660755..35a2cd5 100644
--- a/kernel/rcu/tasks.h
+++ b/kernel/rcu/tasks.h
@@ -1224,6 +1224,40 @@ void show_rcu_tasks_gp_kthreads(void)
}
#endif /* #ifndef CONFIG_TINY_RCU */
+struct rcu_tasks_test_desc {
+ struct rcu_head rh;
+ const char *name;
+ bool notrun;
+};
+
+static struct rcu_tasks_test_desc tests[] = {
+ {
+ .name = "call_rcu_tasks()",
+ /* If not defined, the test is skipped. */
+ .notrun = !IS_ENABLED(CONFIG_TASKS_RCU),
+ },
+ {
+ .name = "call_rcu_tasks_rude()",
+ /* If not defined, the test is skipped. */
+ .notrun = !IS_ENABLED(CONFIG_TASKS_RUDE_RCU),
+ },
+ {
+ .name = "call_rcu_tasks_trace()",
+ /* If not defined, the test is skipped. */
+ .notrun = !IS_ENABLED(CONFIG_TASKS_TRACE_RCU)
+ }
+};
+
+static void test_rcu_tasks_callback(struct rcu_head *rhp)
+{
+ struct rcu_tasks_test_desc *rttd =
+ container_of(rhp, struct rcu_tasks_test_desc, rh);
+
+ pr_info("Callback from %s invoked.\n", rttd->name);
+
+ rttd->notrun = true;
+}
+
void __init rcu_init_tasks_generic(void)
{
#ifdef CONFIG_TASKS_RCU
@@ -1237,7 +1271,45 @@ void __init rcu_init_tasks_generic(void)
#ifdef CONFIG_TASKS_TRACE_RCU
rcu_spawn_tasks_trace_kthread();
#endif
+
+ // Run the self-tests.
+ if (IS_ENABLED(CONFIG_PROVE_RCU)) {
+ pr_info("Running RCU-tasks wait API self tests\n");
+#ifdef CONFIG_TASKS_RCU
+ synchronize_rcu_tasks();
+ call_rcu_tasks(&tests[0].rh, test_rcu_tasks_callback);
+#endif
+
+#ifdef CONFIG_TASKS_RUDE_RCU
+ synchronize_rcu_tasks_rude();
+ call_rcu_tasks_rude(&tests[1].rh, test_rcu_tasks_callback);
+#endif
+
+#ifdef CONFIG_TASKS_TRACE_RCU
+ synchronize_rcu_tasks_trace();
+ call_rcu_tasks_trace(&tests[2].rh, test_rcu_tasks_callback);
+#endif
+ }
+}
+
+static int rcu_tasks_verify_self_tests(void)
+{
+ int ret = 0;
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(tests); i++) {
+ if (!tests[i].notrun) { // still hanging.
+ pr_err("%s has been failed.\n", tests[i].name);
+ ret = -1;
+ }
+ }
+
+ if (ret)
+ WARN_ON(1);
+
+ return ret;
}
+late_initcall(rcu_tasks_verify_self_tests);
#else /* #ifdef CONFIG_TASKS_RCU_GENERIC */
static inline void rcu_tasks_bootup_oddness(void) {}