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 3E83FEB64DD for ; Wed, 5 Jul 2023 07:31:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232311AbjGEHbx (ORCPT ); Wed, 5 Jul 2023 03:31:53 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49966 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232299AbjGEHbu (ORCPT ); Wed, 5 Jul 2023 03:31:50 -0400 Received: from szxga02-in.huawei.com (szxga02-in.huawei.com [45.249.212.188]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 99D5C197; Wed, 5 Jul 2023 00:31:49 -0700 (PDT) Received: from dggpemm500006.china.huawei.com (unknown [172.30.72.56]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4QwrtD3G7NzTm16; Wed, 5 Jul 2023 15:30:44 +0800 (CST) Received: from thunder-town.china.huawei.com (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 15.1.2507.27; Wed, 5 Jul 2023 15:31:46 +0800 From: Zhen Lei To: "Paul E . McKenney" , Frederic Weisbecker , Neeraj Upadhyay , Joel Fernandes , Josh Triplett , Boqun Feng , Steven Rostedt , Mathieu Desnoyers , Lai Jiangshan , Zqiang , , CC: Zhen Lei Subject: [PATCH 2/2] rcu: Don't dump the stalled CPU on where RCU GP kthread last ran twice Date: Wed, 5 Jul 2023 15:30:20 +0800 Message-ID: <20230705073020.2030-3-thunder.leizhen@huawei.com> X-Mailer: git-send-email 2.37.3.windows.1 In-Reply-To: <20230705073020.2030-1-thunder.leizhen@huawei.com> References: <20230705073020.2030-1-thunder.leizhen@huawei.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7BIT Content-Type: text/plain; charset=US-ASCII X-Originating-IP: [10.174.178.55] X-ClientProxiedBy: dggems702-chm.china.huawei.com (10.3.19.179) 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 The stacks of all stalled CPUs will be dumped. If the CPU on where RCU GP kthread last ran is stalled, its stack does not need to be dumped again. Signed-off-by: Zhen Lei --- kernel/rcu/tree_stall.h | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/kernel/rcu/tree_stall.h b/kernel/rcu/tree_stall.h index dcfaa3d5db2cbc7..cc884cd49e026a3 100644 --- a/kernel/rcu/tree_stall.h +++ b/kernel/rcu/tree_stall.h @@ -534,12 +534,14 @@ static void rcu_check_gp_kthread_starvation(void) data_race(READ_ONCE(rcu_state.gp_state)), gpk ? data_race(READ_ONCE(gpk->__state)) : ~0, cpu); if (gpk) { + struct rcu_data *rdp = per_cpu_ptr(&rcu_data, cpu); + pr_err("\tUnless %s kthread gets sufficient CPU time, OOM is now expected behavior.\n", rcu_state.name); pr_err("RCU grace-period kthread stack dump:\n"); sched_show_task(gpk); if (cpu_is_offline(cpu)) { pr_err("RCU GP kthread last ran on offline CPU %d.\n", cpu); - } else { + } else if (!(data_race(READ_ONCE(rdp->mynode->qsmask)) & rdp->grpmask)) { pr_err("Stack dump where RCU GP kthread last ran:\n"); dump_cpu_task(cpu); } -- 2.25.1