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 113E0C433F5 for ; Sun, 9 Oct 2022 20:52:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230246AbiJIUv6 (ORCPT ); Sun, 9 Oct 2022 16:51:58 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43952 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230205AbiJIUvy (ORCPT ); Sun, 9 Oct 2022 16:51:54 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 27FA32AE3C; Sun, 9 Oct 2022 13:51:48 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 4CA87B80D88; Sun, 9 Oct 2022 20:51:47 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 40F2DC433C1; Sun, 9 Oct 2022 20:51:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1665348706; bh=KtOimJEUmu2cKvDrqJBAkgIu9g2nL2KNT4iMyYvQITM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Gv3IR+YCYjRVtNCvEiS2SmobLzt0FEu3vpZTFSn51jXXXSJ2drCuJKYuWe23twnqE WrqgSwM9cI+c2lRRImaSMxXamKZSHXAZfqMzyTMLKso0MbpdkLxOeTDWmAYNRsSnPo CMmcMnn86fHciT51kuYQmrQUp/kpr0cb8G8reSPklaH4sj7rCe9/OHQn8MQeYf+V7g u0a7LEDG90TU7xTNdrFHOQfArWNNnSR2Fn7ivBWqSkHIhGprZ1DjlDHgpgrj7/mTiB NFD0TI9mU9xy+l+v/f/Setvv2WHtap3fUc8BmSeEfdr1SDCObrcFXOIBQe5j6jFZ2M N8ucxE5rKn0RA== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: "Paul E. McKenney" , Sasha Levin , frederic@kernel.org, quic_neeraju@quicinc.com, josh@joshtriplett.org, rcu@vger.kernel.org Subject: [PATCH AUTOSEL 6.0 05/18] rcu-tasks: Ensure RCU Tasks Trace loops have quiescent states Date: Sun, 9 Oct 2022 16:51:22 -0400 Message-Id: <20221009205136.1201774-5-sashal@kernel.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20221009205136.1201774-1-sashal@kernel.org> References: <20221009205136.1201774-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: "Paul E. McKenney" [ Upstream commit d6ad60635cafe900bcd11ad588d8accb36c36b1b ] The RCU Tasks Trace grace-period kthread loops across all CPUs, and there can be quite a few CPUs, with some commercially available systems sporting well over a thousand of them. Some of these loops can feature IPIs, which can take some time. This commit therefore places a call to cond_resched_tasks_rcu_qs() in each such loop. Link: https://docs.google.com/document/d/1V0YnG1HTWMt9WHJjroiJL9lf-hMrud4v8Fn3fhyY0cI/edit?usp=sharing Signed-off-by: Paul E. McKenney Signed-off-by: Sasha Levin --- kernel/rcu/tasks.h | 3 +++ 1 file changed, 3 insertions(+) diff --git a/kernel/rcu/tasks.h b/kernel/rcu/tasks.h index 469bf2a3b505..f5bf6fb430da 100644 --- a/kernel/rcu/tasks.h +++ b/kernel/rcu/tasks.h @@ -1500,6 +1500,7 @@ static void rcu_tasks_trace_pregp_step(struct list_head *hop) if (rcu_tasks_trace_pertask_prep(t, true)) trc_add_holdout(t, hop); rcu_read_unlock(); + cond_resched_tasks_rcu_qs(); } // Only after all running tasks have been accounted for is it @@ -1520,6 +1521,7 @@ static void rcu_tasks_trace_pregp_step(struct list_head *hop) raw_spin_lock_irqsave_rcu_node(rtpcp, flags); } raw_spin_unlock_irqrestore_rcu_node(rtpcp, flags); + cond_resched_tasks_rcu_qs(); } // Re-enable CPU hotplug now that the holdout list is populated. @@ -1619,6 +1621,7 @@ static void check_all_holdout_tasks_trace(struct list_head *hop, trc_del_holdout(t); else if (needreport) show_stalled_task_trace(t, firstreport); + cond_resched_tasks_rcu_qs(); } // Re-enable CPU hotplug now that the holdout list scan has completed. -- 2.35.1