From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-17.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 703BEC4361B for ; Wed, 16 Dec 2020 23:30:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 36B5323718 for ; Wed, 16 Dec 2020 23:30:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726858AbgLPXah (ORCPT ); Wed, 16 Dec 2020 18:30:37 -0500 Received: from mail.kernel.org ([198.145.29.99]:60574 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726806AbgLPXag (ORCPT ); Wed, 16 Dec 2020 18:30:36 -0500 Date: Wed, 16 Dec 2020 15:29:55 -0800 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1608161395; bh=dijIe56HIJQuNec3PZVCHVQQqCbV/T1Tw4BLIPhSFU8=; h=From:To:Cc:Subject:Reply-To:References:In-Reply-To:From; b=NgAKWbSpOZ/1iJte1TCdW7UDeucCJI/LyI4EPTCiMmUCy7yZvCy1U+mH3NoTmZTbk bB7oJ65S/hBhD1bBxdcmhsUhWpbrzDQVPeKSvtuol9YP3XjqNibHsy58W9gJvpy3cK FaMXoc+RY4I9VkbDuHuId+qSeGV85RvUqkL/ancqwbja0wpk5zuB+cH39WN9v57XcZ JYF1yLHwvcluXXuTBOrPBU0tDY1uPGuIk61TjONV043zftVved6CS78V5HqeEX1DdC Hw7+LrPpDQoXXovF6rw01/bJvnYtfKXqXQha+Ze4PgLd2UGslb76KKRjZtYWx2J5LB am85POIthAQgw== From: "Paul E. McKenney" To: Uladzislau Rezki Cc: LKML , RCU , Michael Ellerman , Andrew Morton , Daniel Axtens , Frederic Weisbecker , Neeraj Upadhyay , Joel Fernandes , Peter Zijlstra , Michal Hocko , Thomas Gleixner , "Theodore Y . Ts'o" , Sebastian Andrzej Siewior , Oleksiy Avramchenko Subject: Re: [PATCH 2/2] rcu-tasks: add RCU-tasks self tests Message-ID: <20201216232955.GO2657@paulmck-ThinkPad-P72> Reply-To: paulmck@kernel.org References: <20201209202732.5896-1-urezki@gmail.com> <20201209202732.5896-2-urezki@gmail.com> <20201216154959.GA2408@pc638.lan> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201216154959.GA2408@pc638.lan> User-Agent: Mutt/1.9.4 (2018-02-28) Precedence: bulk List-ID: X-Mailing-List: rcu@vger.kernel.org On Wed, Dec 16, 2020 at 04:49:59PM +0100, Uladzislau Rezki 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. > > > > Signed-off-by: Uladzislau Rezki (Sony) > > --- > > kernel/rcu/tasks.h | 44 ++++++++++++++++++++++++++++++++++++++++++++ > > 1 file changed, 44 insertions(+) > > > > diff --git a/kernel/rcu/tasks.h b/kernel/rcu/tasks.h > > index 67a162949763..9407772780c1 100644 > > --- a/kernel/rcu/tasks.h > > +++ b/kernel/rcu/tasks.h > > @@ -1225,6 +1225,16 @@ void show_rcu_tasks_gp_kthreads(void) > > } > > #endif /* #ifndef CONFIG_TINY_RCU */ > > > > +static struct rcu_head rhp; > > +static int rcu_execurted_test_counter; > > +static int rcu_run_test_counter; > > + > > +static void test_rcu_tasks_callback(struct rcu_head *r) > > +{ > > + pr_info("RCU-tasks test callback executed %d\n", > > + ++rcu_execurted_test_counter); > > +} > > + > > void __init rcu_init_tasks_generic(void) > > { > > #ifdef CONFIG_TASKS_RCU > > @@ -1238,7 +1248,41 @@ void __init rcu_init_tasks_generic(void) > > #ifdef CONFIG_TASKS_TRACE_RCU > > rcu_spawn_tasks_trace_kthread(); > > #endif > > + > > + if (IS_ENABLED(CONFIG_PROVE_RCU)) { > > + pr_info("Running RCU-tasks wait API self tests\n"); > > +#ifdef CONFIG_TASKS_RCU > > + rcu_run_test_counter++; > > + call_rcu_tasks(&rhp, test_rcu_tasks_callback); > > + synchronize_rcu_tasks(); > > +#endif > > + > > +#ifdef CONFIG_TASKS_RUDE_RCU > > + rcu_run_test_counter++; > > + call_rcu_tasks_trace(&rhp, test_rcu_tasks_callback); > > + synchronize_rcu_tasks_rude(); > > +#endif > > + > > +#ifdef CONFIG_TASKS_TRACE_RCU > > + rcu_run_test_counter++; > > + call_rcu_tasks_trace(&rhp, test_rcu_tasks_callback); > > + synchronize_rcu_tasks_trace(); > > +#endif > > + } > > +} > > + > > +static int rcu_tasks_verify_self_tests(void) > > +{ > > + int ret = 0; > > + > > + if (rcu_run_test_counter != rcu_execurted_test_counter) { > > + WARN_ON(1); > > + ret = -1; > > + } > > + > > + return ret; > > } > > +late_initcall(rcu_tasks_verify_self_tests); > > > > #else /* #ifdef CONFIG_TASKS_RCU_GENERIC */ > > static inline void rcu_tasks_bootup_oddness(void) {} > Please find a v2 of the patch that is in question. First version > uses the same rhp for all RCU flavors what is wrong. Initially > i had three different one per one flavor. But for some reason > end up with only one. > > > >From e7c6096af5a7916f29c0b4b05e1644b3b3a6c589 Mon Sep 17 00:00:00 2001 > From: "Uladzislau Rezki (Sony)" > Date: Wed, 9 Dec 2020 21:27:32 +0100 > Subject: [PATCH v2 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) Much improved, thank you! A few more comments below. > --- > kernel/rcu/tasks.h | 69 ++++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 69 insertions(+) > > diff --git a/kernel/rcu/tasks.h b/kernel/rcu/tasks.h > index 36607551f966..7478d912734a 100644 > --- a/kernel/rcu/tasks.h > +++ b/kernel/rcu/tasks.h > @@ -1224,6 +1224,35 @@ void show_rcu_tasks_gp_kthreads(void) > } > #endif /* #ifndef CONFIG_TINY_RCU */ > > +struct test_desc { Please use something like "struct rcu_tasks_test_desc" to help the poor people who might need to grep for this. Feel free to shorten it, but please make it descriptive and thus more likely to stay unique. > + struct rcu_head rh; > + const char *name; > + bool run; If you make this "bool notrun" you don't need to initialize. > +}; > + > +static struct test_desc tests[] = { > + { .name = "call_rcu_tasks()" }, > + { .name = "call_rcu_rude()" }, > + { .name = "call_rcu_trace()" }, > +}; > + > +static int rcu_executed_test_counter; > + > +static void test_rcu_tasks_callback(struct rcu_head *rhp) > +{ struct rcu_tasks_test_desc *rttdp; > + int i; > + > + pr_info("RCU-tasks test callback executed %d\n", > + ++rcu_executed_test_counter); rttdp = container_of(rhp, rh, struct rcu_tasks_test_desc); rttdp->notrun = true; Or I suppose: container_of(rhp, rh, struct rcu_tasks_test_desc)->notrun = true; Then the loop below can go away. > + > + for (i = 0; i < ARRAY_SIZE(tests); i++) { > + if (rhp == &tests[i].rh) { > + tests[i].run = false; > + break; > + } > + } > +} > + > void __init rcu_init_tasks_generic(void) > { > #ifdef CONFIG_TASKS_RCU > @@ -1237,7 +1266,47 @@ 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 > + tests[0].run = true; The s/run/notrun/ allows the three initializations of .run to go away. > + call_rcu_tasks(&tests[0].rh, test_rcu_tasks_callback); > + synchronize_rcu_tasks(); Why not reverse the order of these two statements? That would test call_rcu_tasks*()'s ability to do a grace period on their own, without help from the corresponding synchronize_rcu_tasks*(). > +#endif > + > +#ifdef CONFIG_TASKS_RUDE_RCU > + tests[1].run = true; > + call_rcu_tasks_rude(&tests[1].rh, test_rcu_tasks_callback); > + synchronize_rcu_tasks_rude(); > +#endif > + > +#ifdef CONFIG_TASKS_TRACE_RCU > + tests[2].run = true; > + call_rcu_tasks_trace(&tests[2].rh, test_rcu_tasks_callback); > + synchronize_rcu_tasks_trace(); > +#endif > + } > +} > + > +static int rcu_tasks_verify_self_tests(void) > +{ > + int ret, i; Why not initialize "ret" in the declaration? > + > + for (i = 0, ret = 0; i < ARRAY_SIZE(tests); i++) { > + if (tests[i].run) { // 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) {} > -- > 2.20.1 Again, much improved! Thanx, Paul