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=-19.3 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham 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 9D533C433DB for ; Wed, 6 Jan 2021 04:51:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 62F3422BF3 for ; Wed, 6 Jan 2021 04:51:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726925AbhAFEuS (ORCPT ); Tue, 5 Jan 2021 23:50:18 -0500 Received: from mail.kernel.org ([198.145.29.99]:33366 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726345AbhAFEuR (ORCPT ); Tue, 5 Jan 2021 23:50:17 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id B1DA5230F9; Wed, 6 Jan 2021 04:48:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1609908536; bh=mYC8n2tBoXxFl/HWwwJQ1b2I6TPQeCleiL/VfsurVHY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=hnVvRZmVFkw1E/Z7mICfj3thmjT88JXkcECr+CS7+8B6IN06cDTBsU98ISUFUnzjF MzOLqku3auq/RF3wOVuk5ZBb9Ou1WjYA4Ze6pOJWK+DTEJ/Y0IcR2dhVKPaFeUZS+A 0CkqqHe4v9A+Xk4D/XiOvmdCKHoS1gTf036ypLrmbX56bJbsejhIZaB57Lg++IGR8A ukBi0Da4C7IQb+Ry/SEpx3B9W7XDzHKC+zUaNZuhJhqcDyL87sjMLfrtikeTrSxCwL RdmqTRGk5PTEWMYIRdRw2NBUF/kCZ/vpyI5lTLKuHMJaVMjcJ+O3hwp7sxoR6DXcEn QDoWdJB59rMMA== From: paulmck@kernel.org To: rcu@vger.kernel.org Cc: linux-kernel@vger.kernel.org, kernel-team@fb.com, mingo@kernel.org, jiangshanlai@gmail.com, akpm@linux-foundation.org, mathieu.desnoyers@efficios.com, josh@joshtriplett.org, tglx@linutronix.de, peterz@infradead.org, rostedt@goodmis.org, dhowells@redhat.com, edumazet@google.com, fweisbec@gmail.com, oleg@redhat.com, joel@joelfernandes.org, Frederic Weisbecker , Neeraj Upadhyay , "Paul E . McKenney" Subject: [PATCH tip/core/rcu 09/21] rcu/nocb: Flush bypass before setting SEGCBLIST_SOFTIRQ_ONLY Date: Tue, 5 Jan 2021 20:48:41 -0800 Message-Id: <20210106044853.20812-9-paulmck@kernel.org> X-Mailer: git-send-email 2.9.5 In-Reply-To: <20210106013950.GA14663@paulmck-ThinkPad-P72> References: <20210106013950.GA14663@paulmck-ThinkPad-P72> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Frederic Weisbecker This commit flushes the bypass queue and sets state to avoid its being refilled before switching to the final de-offloaded state. To avoid refilling, this commit sets SEGCBLIST_SOFTIRQ_ONLY before re-enabling IRQs. Cc: Josh Triplett Cc: Steven Rostedt Cc: Mathieu Desnoyers Cc: Lai Jiangshan Cc: Joel Fernandes Cc: Neeraj Upadhyay Cc: Thomas Gleixner Inspired-by: Paul E. McKenney Tested-by: Boqun Feng Signed-off-by: Frederic Weisbecker Signed-off-by: Paul E. McKenney --- kernel/rcu/tree_plugin.h | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h index c88ad62..35dc9b3 100644 --- a/kernel/rcu/tree_plugin.h +++ b/kernel/rcu/tree_plugin.h @@ -2339,12 +2339,21 @@ static int __rcu_nocb_rdp_deoffload(struct rcu_data *rdp) swait_event_exclusive(rdp->nocb_state_wq, !rcu_segcblist_test_flags(cblist, SEGCBLIST_KTHREAD_CB | SEGCBLIST_KTHREAD_GP)); - /* Make sure nocb timer won't stay around */ rcu_nocb_lock_irqsave(rdp, flags); + /* Make sure nocb timer won't stay around */ WRITE_ONCE(rdp->nocb_defer_wakeup, RCU_NOCB_WAKE_OFF); rcu_nocb_unlock_irqrestore(rdp, flags); del_timer_sync(&rdp->nocb_timer); + /* + * Flush bypass. While IRQs are disabled and once we set + * SEGCBLIST_SOFTIRQ_ONLY, no callback is supposed to be + * enqueued on bypass. + */ + rcu_nocb_lock_irqsave(rdp, flags); + rcu_nocb_flush_bypass(rdp, NULL, jiffies); + rcu_nocb_unlock_irqrestore(rdp, flags); + return ret; } -- 2.9.5