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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1609BC00140 for ; Fri, 5 Aug 2022 08:10:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240413AbiHEIKC (ORCPT ); Fri, 5 Aug 2022 04:10:02 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35652 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234312AbiHEIKA (ORCPT ); Fri, 5 Aug 2022 04:10:00 -0400 Received: from szxga02-in.huawei.com (szxga02-in.huawei.com [45.249.212.188]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E57C174E28; Fri, 5 Aug 2022 01:09:54 -0700 (PDT) Received: from dggpemm500024.china.huawei.com (unknown [172.30.72.57]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4LzdSs1ktGzWfKZ; Fri, 5 Aug 2022 16:05:49 +0800 (CST) Received: from dggpemm500006.china.huawei.com (7.185.36.236) by dggpemm500024.china.huawei.com (7.185.36.203) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Fri, 5 Aug 2022 16:09:25 +0800 Received: from [10.174.178.55] (10.174.178.55) by dggpemm500006.china.huawei.com (7.185.36.236) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Fri, 5 Aug 2022 16:09:24 +0800 Subject: Re: [PATCH v4 0/2] rcu: Display registers of self-detected stall as far as possible To: CC: Ingo Molnar , Peter Zijlstra , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , "Mel Gorman" , Daniel Bristot de Oliveira , Valentin Schneider , , Frederic Weisbecker , Neeraj Upadhyay , Josh Triplett , "Mathieu Desnoyers" , Lai Jiangshan , Joel Fernandes , References: <20220804023420.1663-1-thunder.leizhen@huawei.com> <20220804180958.GQ2125313@paulmck-ThinkPad-P17-Gen-1> From: "Leizhen (ThunderTown)" Message-ID: <5da6eaf0-6570-caff-4eec-79d73b4f5062@huawei.com> Date: Fri, 5 Aug 2022 16:09:23 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.7.0 MIME-Version: 1.0 In-Reply-To: <20220804180958.GQ2125313@paulmck-ThinkPad-P17-Gen-1> Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.174.178.55] X-ClientProxiedBy: dggems701-chm.china.huawei.com (10.3.19.178) To dggpemm500006.china.huawei.com (7.185.36.236) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2022/8/5 2:09, Paul E. McKenney wrote: > On Thu, Aug 04, 2022 at 10:34:18AM +0800, Zhen Lei wrote: >> v3 --> v4: >> 1. To avoid undo/redo, merge patch 1-2 in v3 into one. >> >> v2 --> v3: >> 1. Patch 1 Add trigger_single_cpu_backtrace(cpu) in synchronize_rcu_expedited_wait() >> Subsequently, we can see that all callers of dump_cpu_task() try >> trigger_single_cpu_backtrace() first. Then I do the cleanup in Patch 2. >> 2. Patch 3, as Paul E. McKenney's suggestion, push the code into dump_cpu_task(). >> >> For newcomers: >> Currently, dump_cpu_task() is mainly used by RCU, in order to dump the >> stack traces of the current task of the specified CPU when a rcu stall >> is detected. >> >> For architectures that do not support NMI interrupts, registers is not >> printed when rcu stall is self-detected. This patch series improve it. > > Thank you! I have queued both for further testing and review. I had > to rebase them to the -rcu tree's "dev" branch. There was one trivial > conflict, but could you please check the resulting commits, both for > my wordsmithing and to make sure that your changes still work in your > environment? (I do not have access to that sort of hardware.) Your description is much clearer than mine, thanks. I will test it tomorrow, the international network speed is too slow during the day. > > In the future, could you please send your patches against the -rcu > tree's "dev" branch? Okay, no problem. I'll do it next time. > > Thanx, Paul > >> v2: >> https://lkml.org/lkml/2022/7/27/1800 >> >> Zhen Lei (2): >> sched/debug: Try trigger_single_cpu_backtrace(cpu) in dump_cpu_task() >> sched/debug: Show the registers of 'current' in dump_cpu_task() >> >> kernel/rcu/tree_stall.h | 8 +++----- >> kernel/sched/core.c | 14 ++++++++++++++ >> kernel/smp.c | 3 +-- >> 3 files changed, 18 insertions(+), 7 deletions(-) >> >> -- >> 2.25.1 >> > . > -- Regards, Zhen Lei