From patchwork Thu Feb 23 06:30:22 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Zqiang X-Patchwork-Id: 13149887 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 A8700C61DA4 for ; Thu, 23 Feb 2023 06:25:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233311AbjBWGZe (ORCPT ); Thu, 23 Feb 2023 01:25:34 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53226 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232238AbjBWGZe (ORCPT ); Thu, 23 Feb 2023 01:25:34 -0500 Received: from mga03.intel.com (mga03.intel.com [134.134.136.65]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5B2703803F; Wed, 22 Feb 2023 22:25:33 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1677133533; x=1708669533; h=from:to:cc:subject:date:message-id:mime-version: content-transfer-encoding; bh=TgLi49IW34LbRGQNmGM2xD5vJvj6jAn4cnTtBB1bWqc=; b=H07Fn3K9MmxNGHH7M/vAf5OwnxKIhST66ntVEM41Co1sOUgiCHB1r4cc HNldFR26hGJwbH1vXo6ZWvXeNNnqM+/uSP/hd/+/wmmyDw6qKpKP+qJCv N7rokFfwA4Pq9VFJ+7UkoS6+Eglh5j8t77YSdW0eXRwriFeeExhfGK8QU TyNa2SIxg4ZqVdUfpffG5utgMrO2QwKAAWKXh9exUbg58JKizMq3rTn2R SlS/zUeJNFE3P8n19eHyio3CpcGA7hsjlBokWzq66EL3RYwuFR2SVbb4a d1K5xxxuGwMZSBG0EcoYjq/d9LLhDMgc7kc5LfozyhbcF+oO+kC0FDjlM Q==; X-IronPort-AV: E=McAfee;i="6500,9779,10629"; a="335331921" X-IronPort-AV: E=Sophos;i="5.97,320,1669104000"; d="scan'208";a="335331921" Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by orsmga103.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 22 Feb 2023 22:25:31 -0800 X-IronPort-AV: E=McAfee;i="6500,9779,10629"; a="741144252" X-IronPort-AV: E=Sophos;i="5.97,320,1669104000"; d="scan'208";a="741144252" Received: from zq-optiplex-7090.bj.intel.com ([10.238.156.129]) by fmsmga004-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 22 Feb 2023 22:25:29 -0800 From: Zqiang To: paulmck@kernel.org, frederic@kernel.org, quic_neeraju@quicinc.com, joel@joelfernandes.org Cc: rcu@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH] rcu-tasks: Directly invoke rcuwait_wake_up() in call_rcu_tasks_generic() Date: Thu, 23 Feb 2023 14:30:22 +0800 Message-Id: <20230223063022.2592212-1-qiang1.zhang@intel.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: rcu@vger.kernel.org According to commit '3063b33a347c ("Avoid raw-spinlocked wakeups from call_rcu_tasks_generic()")', the grace-period kthread is delayed to wakeup using irq_work_queue() is because if the caller of call_rcu_tasks_generic() holds a raw spinlock, when the kernel is built with CONFIG_PROVE_RAW_LOCK_NESTING=y, due to a spinlock will be hold in wake_up(), so the lockdep splats will happen. but now using rcuwait_wake_up() to wakeup grace-period kthread instead of wake_up(), in rcuwait_wake_up() no spinlock will be acquired, so this commit remove using irq_work_queue(), invoke rcuwait_wake_up() directly in call_rcu_tasks_generic(). Signed-off-by: Zqiang --- kernel/rcu/tasks.h | 16 +--------------- 1 file changed, 1 insertion(+), 15 deletions(-) diff --git a/kernel/rcu/tasks.h b/kernel/rcu/tasks.h index baf7ec178155..757b8c6da1ad 100644 --- a/kernel/rcu/tasks.h +++ b/kernel/rcu/tasks.h @@ -39,7 +39,6 @@ struct rcu_tasks_percpu { unsigned long rtp_jiffies; unsigned long rtp_n_lock_retries; struct work_struct rtp_work; - struct irq_work rtp_irq_work; struct rcu_head barrier_q_head; struct list_head rtp_blkd_tasks; int cpu; @@ -112,12 +111,9 @@ struct rcu_tasks { char *kname; }; -static void call_rcu_tasks_iw_wakeup(struct irq_work *iwp); - #define DEFINE_RCU_TASKS(rt_name, gp, call, n) \ static DEFINE_PER_CPU(struct rcu_tasks_percpu, rt_name ## __percpu) = { \ .lock = __RAW_SPIN_LOCK_UNLOCKED(rt_name ## __percpu.cbs_pcpu_lock), \ - .rtp_irq_work = IRQ_WORK_INIT_HARD(call_rcu_tasks_iw_wakeup), \ }; \ static struct rcu_tasks rt_name = \ { \ @@ -273,16 +269,6 @@ static void cblist_init_generic(struct rcu_tasks *rtp) pr_info("%s: Setting shift to %d and lim to %d.\n", __func__, data_race(rtp->percpu_enqueue_shift), data_race(rtp->percpu_enqueue_lim)); } -// IRQ-work handler that does deferred wakeup for call_rcu_tasks_generic(). -static void call_rcu_tasks_iw_wakeup(struct irq_work *iwp) -{ - struct rcu_tasks *rtp; - struct rcu_tasks_percpu *rtpcp = container_of(iwp, struct rcu_tasks_percpu, rtp_irq_work); - - rtp = rtpcp->rtpp; - rcuwait_wake_up(&rtp->cbs_wait); -} - // Enqueue a callback for the specified flavor of Tasks RCU. static void call_rcu_tasks_generic(struct rcu_head *rhp, rcu_callback_t func, struct rcu_tasks *rtp) @@ -334,7 +320,7 @@ static void call_rcu_tasks_generic(struct rcu_head *rhp, rcu_callback_t func, rcu_read_unlock(); /* We can't create the thread unless interrupts are enabled. */ if (needwake && READ_ONCE(rtp->kthread_ptr)) - irq_work_queue(&rtpcp->rtp_irq_work); + rcuwait_wake_up(&rtp->cbs_wait); } // RCU callback function for rcu_barrier_tasks_generic().