From: Uladzislau Rezki <urezki@gmail.com>
To: Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
"Paul E . McKenney" <paulmck@kernel.org>
Cc: "Uladzislau Rezki (Sony)" <urezki@gmail.com>,
LKML <linux-kernel@vger.kernel.org>, RCU <rcu@vger.kernel.org>,
"Paul E . McKenney" <paulmck@kernel.org>,
Michael Ellerman <mpe@ellerman.id.au>,
Andrew Morton <akpm@linux-foundation.org>,
Daniel Axtens <dja@axtens.net>,
Frederic Weisbecker <frederic@kernel.org>,
Neeraj Upadhyay <neeraju@codeaurora.org>,
Joel Fernandes <joel@joelfernandes.org>,
Peter Zijlstra <peterz@infradead.org>,
Michal Hocko <mhocko@suse.com>,
Thomas Gleixner <tglx@linutronix.de>,
"Theodore Y . Ts'o" <tytso@mit.edu>,
Oleksiy Avramchenko <oleksiy.avramchenko@sonymobile.com>
Subject: Re: [PATCH 2/2] rcu-tasks: add RCU-tasks self tests
Date: Fri, 12 Feb 2021 22:12:07 +0100 [thread overview]
Message-ID: <20210212211207.GA2046@pc638.lan> (raw)
In-Reply-To: <20210212192059.wytqwdf4qm4rnq3d@linutronix.de>
On Fri, Feb 12, 2021 at 08:20:59PM +0100, Sebastian Andrzej Siewior wrote:
> On 2020-12-09 21:27:32 [+0100], Uladzislau Rezki (Sony) wrote:
> > Add self tests for checking of RCU-tasks API functionality.
> > It covers:
> > - wait API functions;
> > - invoking/completion call_rcu_tasks*().
> >
> > Self-tests are run when CONFIG_PROVE_RCU kernel parameter is set.
>
> I just bisected to this commit. By booting with `threadirqs' I end up
> with:
> [ 0.176533] Running RCU-tasks wait API self tests
>
> No stall warning or so.
> It boots again with:
>
> diff --git a/init/main.c b/init/main.c
> --- a/init/main.c
> +++ b/init/main.c
> @@ -1489,6 +1489,7 @@ void __init console_on_rootfs(void)
> fput(file);
> }
>
> +void rcu_tasks_initiate_self_tests(void);
> static noinline void __init kernel_init_freeable(void)
> {
> /*
> @@ -1514,6 +1515,7 @@ static noinline void __init kernel_init_freeable(void)
>
> rcu_init_tasks_generic();
> do_pre_smp_initcalls();
> + rcu_tasks_initiate_self_tests();
> lockup_detector_init();
>
> smp_init();
> diff --git a/kernel/rcu/tasks.h b/kernel/rcu/tasks.h
> --- a/kernel/rcu/tasks.h
> +++ b/kernel/rcu/tasks.h
> @@ -1266,7 +1266,7 @@ static void test_rcu_tasks_callback(struct rcu_head *rhp)
> rttd->notrun = true;
> }
>
> -static void rcu_tasks_initiate_self_tests(void)
> +void rcu_tasks_initiate_self_tests(void)
> {
> pr_info("Running RCU-tasks wait API self tests\n");
> #ifdef CONFIG_TASKS_RCU
> @@ -1322,7 +1322,6 @@ void __init rcu_init_tasks_generic(void)
> #endif
>
> // Run the self-tests.
> - rcu_tasks_initiate_self_tests();
> }
>
> #else /* #ifdef CONFIG_TASKS_RCU_GENERIC */
>
> > Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
>
> Sebastian
>
We should be able to use call_rcu_tasks() in the *initcall() callbacks.
The problem is that, ksoftirqd threads are not spawned by the time when
an rcu_init_tasks_generic() is invoked:
diff --git a/init/main.c b/init/main.c
index c68d784376ca..e6106bb12b2d 100644
--- a/init/main.c
+++ b/init/main.c
@@ -954,7 +954,6 @@ asmlinkage __visible void __init __no_sanitize_address start_kernel(void)
rcu_init_nohz();
init_timers();
hrtimers_init();
- softirq_init();
timekeeping_init();
/*
@@ -1512,6 +1511,7 @@ static noinline void __init kernel_init_freeable(void)
init_mm_internals();
+ softirq_init();
rcu_init_tasks_generic();
do_pre_smp_initcalls();
lockup_detector_init();
diff --git a/kernel/softirq.c b/kernel/softirq.c
index 9d71046ea247..cafa55c496d0 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -630,6 +630,7 @@ void __init softirq_init(void)
&per_cpu(tasklet_hi_vec, cpu).head;
}
+ spawn_ksoftirqd();
open_softirq(TASKLET_SOFTIRQ, tasklet_action);
open_softirq(HI_SOFTIRQ, tasklet_hi_action);
}
@@ -732,7 +733,6 @@ static __init int spawn_ksoftirqd(void)
return 0;
}
-early_initcall(spawn_ksoftirqd);
/*
* [ These __weak aliases are kept in a separate compilation unit, so that
Any thoughts?
--
Vlad Rezki
next prev parent reply other threads:[~2021-02-12 21:13 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-09 20:27 [PATCH 1/2] rcu-tasks: move RCU-tasks initialization out of core_initcall() Uladzislau Rezki (Sony)
2020-12-09 20:27 ` [PATCH 2/2] rcu-tasks: add RCU-tasks self tests Uladzislau Rezki (Sony)
2020-12-16 15:49 ` Uladzislau Rezki
2020-12-16 23:29 ` Paul E. McKenney
2020-12-21 15:38 ` Uladzislau Rezki
2020-12-21 17:18 ` Paul E. McKenney
2020-12-21 18:45 ` Uladzislau Rezki
2020-12-21 19:29 ` Paul E. McKenney
2020-12-21 19:48 ` Uladzislau Rezki
2020-12-21 20:45 ` Paul E. McKenney
2020-12-21 21:28 ` Uladzislau Rezki
2021-02-12 19:20 ` Sebastian Andrzej Siewior
2021-02-12 21:12 ` Uladzislau Rezki [this message]
2021-02-12 23:48 ` Paul E. McKenney
2021-02-13 0:37 ` Paul E. McKenney
2021-02-13 0:43 ` Paul E. McKenney
2021-02-13 11:30 ` Uladzislau Rezki
2021-02-13 16:45 ` Paul E. McKenney
2021-02-13 20:00 ` Uladzislau Rezki
2021-02-15 11:28 ` Sebastian Andrzej Siewior
2021-02-16 17:30 ` Paul E. McKenney
2021-02-17 14:47 ` Masami Hiramatsu
2021-02-17 18:17 ` Paul E. McKenney
2021-02-18 5:03 ` Masami Hiramatsu
2021-02-18 8:36 ` Uladzislau Rezki
2021-02-18 14:29 ` Masami Hiramatsu
2020-12-09 20:37 ` [PATCH 1/2] rcu-tasks: move RCU-tasks initialization out of core_initcall() Uladzislau Rezki
2020-12-10 13:39 ` Daniel Axtens
2020-12-10 17:32 ` Paul E. McKenney
2020-12-10 18:17 ` Uladzislau Rezki
2020-12-10 3:26 ` Paul E. McKenney
2020-12-10 13:04 ` Uladzislau Rezki
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