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=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 702D3C4363A for ; Fri, 23 Oct 2020 14:47:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 23D9920EDD for ; Fri, 23 Oct 2020 14:47:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1603464450; bh=mmBI23rjjBmPGjD8SbLtdgVhsw2qBsYlz8/3jt8pg4A=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=jfy9KS1bDRQXt+qwbDjFJxEK0WRmUq5RvLOnJ3W+RBeTZKuEVmhATt59eQ3+nJx6m zdDIB/n2OHrsPeqTCV6Z73pqZJSliDC3zjAxaYT+AU4eEtsDJV6oT0qIUfWcrAxZv0 NAVBxQ+7UT2zdoTHtu6DJWeTOTJLJ4Zrf8qPHhdg= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750770AbgJWOr1 (ORCPT ); Fri, 23 Oct 2020 10:47:27 -0400 Received: from mail.kernel.org ([198.145.29.99]:33426 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750758AbgJWOrW (ORCPT ); Fri, 23 Oct 2020 10:47:22 -0400 Received: from localhost.localdomain (unknown [176.167.163.208]) (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 7F24F24641; Fri, 23 Oct 2020 14:47:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1603464441; bh=mmBI23rjjBmPGjD8SbLtdgVhsw2qBsYlz8/3jt8pg4A=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=H4zUl0pv4yew5LXQ/jUTp0/zpzlhPKT0LutIspUzkQJVGFevVo6elHSCzf2qvmIgn CPR4CaXBpskuAzka35zpe73y6bm/s/3fP7sUFfkyAT3zhqE+UP2Ys7j8eYCRBocyyX e6QQfxz0mCgRKhrNxDVUf+diaCIW5e5Qcj1kx2/M= From: Frederic Weisbecker To: LKML Cc: Frederic Weisbecker , Steven Rostedt , Mathieu Desnoyers , "Paul E . McKenney" , Lai Jiangshan , Neeraj Upadhyay , Joel Fernandes , Josh Triplett Subject: [PATCH 10/16] rcu: Flush bypass before setting SEGCBLIST_SOFTIRQ_ONLY Date: Fri, 23 Oct 2020 16:46:43 +0200 Message-Id: <20201023144649.53046-11-frederic@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20201023144649.53046-1-frederic@kernel.org> References: <20201023144649.53046-1-frederic@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Make sure to handle the pending bypass queue before we switch to the final de-offload state. We'll have to be careful and later set SEGCBLIST_SOFTIRQ_ONLY before re-enabling again IRQs, or new bypass callbacks could be queued in the meantine. 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 --- kernel/rcu/tree_plugin.h | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h index c44b83b79196..49bd42995ae7 100644 --- a/kernel/rcu/tree_plugin.h +++ b/kernel/rcu/tree_plugin.h @@ -2342,12 +2342,19 @@ 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)); + rcu_nocb_lock_irqsave(rdp, flags); /* Make sure nocb timer won't stay around */ - rcu_nocb_lock_irqsave(rdp, flags); 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_flush_bypass(rdp, NULL, jiffies); + rcu_nocb_unlock_irqrestore(rdp, flags); + return ret; } -- 2.25.1