linux-kernel - Re: [PATCH 2/2] rcu-tasks: add RCU-tasks self tests

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Date:   Mon, 21 Dec 2020 19:45:39 +0100
From:   Uladzislau Rezki <urezki@...il.com>
To:     "Paul E. McKenney" <paulmck@...nel.org>
Cc:     Uladzislau Rezki <urezki@...il.com>,
        LKML <linux-kernel@...r.kernel.org>, RCU <rcu@...r.kernel.org>,
        Michael Ellerman <mpe@...erman.id.au>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Daniel Axtens <dja@...ens.net>,
        Frederic Weisbecker <frederic@...nel.org>,
        Neeraj Upadhyay <neeraju@...eaurora.org>,
        Joel Fernandes <joel@...lfernandes.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Michal Hocko <mhocko@...e.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        "Theodore Y . Ts'o" <tytso@....edu>,
        Sebastian Andrzej Siewior <bigeasy@...utronix.de>,
        Oleksiy Avramchenko <oleksiy.avramchenko@...ymobile.com>
Subject: Re: [PATCH 2/2] rcu-tasks: add RCU-tasks self tests

On Mon, Dec 21, 2020 at 09:18:05AM -0800, Paul E. McKenney wrote:
> 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@...il.com>
> > 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@...il.com>
> 
> 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@...il.com>
> 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@...il.com>
>     Signed-off-by: Paul E. McKenney <paulmck@...nel.org>
> 
> 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);
That is fine! We can output the name instead of executed counter.
Doing so makes it completely clear who triggers the callback.

--
Vlad Rezki