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=-14.2 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable 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 9B444C433E0 for ; Fri, 12 Feb 2021 21:13:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6AE7A64DA1 for ; Fri, 12 Feb 2021 21:13:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231663AbhBLVNA (ORCPT ); Fri, 12 Feb 2021 16:13:00 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39602 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231175AbhBLVMw (ORCPT ); Fri, 12 Feb 2021 16:12:52 -0500 Received: from mail-lj1-x22c.google.com (mail-lj1-x22c.google.com [IPv6:2a00:1450:4864:20::22c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 04EBBC061574; Fri, 12 Feb 2021 13:12:12 -0800 (PST) Received: by mail-lj1-x22c.google.com with SMTP id q14so691141ljp.4; Fri, 12 Feb 2021 13:12:11 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:date:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=SS2KGzlfjLWSOo4Rl+0SlDA0DNdaHfog9YBOFxDk0j0=; b=ux6zsDF3Nb15pW7IuLzOiLjSa0tKh6CoCstGIBj+fZZc+eyQe1XahpLewgPHlQ2bOv tW31+KKmhrtu99jQP3/sYZp3H3pLBOOgKi9vde/Ae8UwM1/suD0vFjraUKLj+1Bu4BNQ yqc9QtN0p9PpP1bicfnpTrElZP+TPdU+pHlVdjd4gmpAzXPQf/Y09B26D135Zp9qUlMz zuG7kL8KYzvG4RwjSXfItm5CtkQkJWotCc2EZ0hWnvDqxwzXtUcDyubCUIyxtMSbzeDS bojauVV9aiHMixXnW6c5YuTy4f4A/P3hP4JQGprNO9M1hqv8r5A3Zn+gK1fKQbzgmmUo KQ8A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:date:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=SS2KGzlfjLWSOo4Rl+0SlDA0DNdaHfog9YBOFxDk0j0=; b=HaMaDWpvEWsVMFFrtFdve9VtFNBo3LA/FKcRJuZVeOE3zaRckU1YGMtJcZEj5nXxqi yoTKXLfk73WI7xfI9V3u7KsEEwwCxDbYFMCJjpJBGcEoy2cin9Qjogj5zZ7XbaqJFI7L Sn1spBaYanmnUFEYSPvsxOjF0F7xOnnxBcrdenecuqQLX41MHnCRiPczm5ZCJhF7EhM4 IuxqIIjPGY0V/poUIW772acEkT/fOyhYhkLBlJF3eAJj38tLGIzvEgSxuJVS9vtTVX+8 MQ568Jy7Zwh8JrRrAJ7iY6sRsseyqojPxYz3S+mDARFE6wZEQWSxumtycwRm2uXrJgiE ayjA== X-Gm-Message-State: AOAM532lN+HUL3gVYeOYV7mpDcP2y7/2Jqj0zeXkvJd7JjQBEypaXSA1 2nkZTTAk/K8r2jj3xIct84E= X-Google-Smtp-Source: ABdhPJzj0ixu8+ZiZkByG5Hd0+iUPqtddx7ZwKYg4OYtrFpJ85SICzds6iEvKZ3NM+3xiSmK+JSn/w== X-Received: by 2002:a2e:88d4:: with SMTP id a20mr2589022ljk.303.1613164330443; Fri, 12 Feb 2021 13:12:10 -0800 (PST) Received: from pc638.lan (h5ef52e3d.seluork.dyn.perspektivbredband.net. [94.245.46.61]) by smtp.gmail.com with ESMTPSA id a23sm794577lfl.6.2021.02.12.13.12.09 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 12 Feb 2021 13:12:09 -0800 (PST) From: Uladzislau Rezki X-Google-Original-From: Uladzislau Rezki Date: Fri, 12 Feb 2021 22:12:07 +0100 To: Sebastian Andrzej Siewior , "Paul E . McKenney" Cc: "Uladzislau Rezki (Sony)" , LKML , RCU , "Paul E . McKenney" , Michael Ellerman , Andrew Morton , Daniel Axtens , Frederic Weisbecker , Neeraj Upadhyay , Joel Fernandes , Peter Zijlstra , Michal Hocko , Thomas Gleixner , "Theodore Y . Ts'o" , Oleksiy Avramchenko Subject: Re: [PATCH 2/2] rcu-tasks: add RCU-tasks self tests Message-ID: <20210212211207.GA2046@pc638.lan> References: <20201209202732.5896-1-urezki@gmail.com> <20201209202732.5896-2-urezki@gmail.com> <20210212192059.wytqwdf4qm4rnq3d@linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210212192059.wytqwdf4qm4rnq3d@linutronix.de> User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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) > > 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