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=-13.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 3BC7CC4742C for ; Fri, 13 Nov 2020 12:14:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DFB6B2085B for ; Fri, 13 Nov 2020 12:14:32 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="H02HBad2" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726823AbgKMMOb (ORCPT ); Fri, 13 Nov 2020 07:14:31 -0500 Received: from mail.kernel.org ([198.145.29.99]:48050 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726642AbgKMMOY (ORCPT ); Fri, 13 Nov 2020 07:14:24 -0500 Received: from localhost.localdomain (unknown [176.167.84.141]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 04A4622250; Fri, 13 Nov 2020 12:14:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1605269663; bh=cwrRyVzdGrrcuNdx6Yw81kvmDTaQJhzLcZbdSDJINHQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=H02HBad2C6f3vjBnL1cWerFhqhOorUEXCx0z/1at6pqJ0kuoN9iI+y44yHR2fzrS9 XIe8SYNdMlRNtzanjPv0OxPMDjAxeNgYrqGIbwfsWxJ8cOMp7AeRga86L5M8nDoeXy lxWoW5Gvy6Yr1yFbn9DZgvHWBgjYKNytTMEfNbF8= From: Frederic Weisbecker To: "Paul E . McKenney" Cc: LKML , Frederic Weisbecker , Steven Rostedt , Thomas Gleixner , Mathieu Desnoyers , Boqun Feng , Lai Jiangshan , Neeraj Upadhyay , Joel Fernandes , Josh Triplett , rcu@vger.kernel.org Subject: [PATCH 13/19] rcu/nocb: Locally accelerate callbacks as long as offloading isn't complete Date: Fri, 13 Nov 2020 13:13:28 +0100 Message-Id: <20201113121334.166723-14-frederic@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20201113121334.166723-1-frederic@kernel.org> References: <20201113121334.166723-1-frederic@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The local callbacks processing checks if some callbacks need acceleration. Keep that behaviour under nocb lock protection when rcu_core() executes concurrently with GP/CB kthreads. Inspired-by: Paul E. McKenney Signed-off-by: Frederic Weisbecker Cc: Paul E. McKenney Cc: Josh Triplett Cc: Steven Rostedt Cc: Mathieu Desnoyers Cc: Lai Jiangshan Cc: Joel Fernandes Cc: Neeraj Upadhyay Cc: Thomas Gleixner Cc: Boqun Feng --- kernel/rcu/tree.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index cc141337f3f9..b24d60a52f34 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -2690,7 +2690,6 @@ static __latent_entropy void rcu_core(void) unsigned long flags; struct rcu_data *rdp = raw_cpu_ptr(&rcu_data); struct rcu_node *rnp = rdp->mynode; - const bool offloaded = rcu_segcblist_is_offloaded(&rdp->cblist); const bool do_batch = !rcu_segcblist_completely_offloaded(&rdp->cblist); if (cpu_is_offline(smp_processor_id())) @@ -2711,11 +2710,11 @@ static __latent_entropy void rcu_core(void) /* No grace period and unregistered callbacks? */ if (!rcu_gp_in_progress() && - rcu_segcblist_is_enabled(&rdp->cblist) && !offloaded) { - local_irq_save(flags); + rcu_segcblist_is_enabled(&rdp->cblist) && do_batch) { + rcu_nocb_lock_irqsave(rdp, flags); if (!rcu_segcblist_restempty(&rdp->cblist, RCU_NEXT_READY_TAIL)) rcu_accelerate_cbs_unlocked(rnp, rdp); - local_irq_restore(flags); + rcu_nocb_unlock_irqrestore(rdp, flags); } rcu_check_gp_start_stall(rnp, rdp, rcu_jiffies_till_stall_check()); -- 2.25.1