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=-14.6 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 58A24C43463 for ; Mon, 21 Sep 2020 12:44:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 113FB21D43 for ; Mon, 21 Sep 2020 12:44:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600692267; bh=iSQLytuvoTVSkVFQJBym4elXGfzuYLVgReaXc9VqAPw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=sfOUeVhY8e3NmWwhgTwUIIGSzKo3O3lE/rZqWsHOHnlR4vymhTNU66VNtdKzc9zFu 9vBY74TLx5/6saMxj970ofmjj1ItvaQcDsETLNa5EesuFTwoKopBHIVLTKv319t8rM Ry6ylgAQJ9VOv+vYgiunFj+aMuS8JAQ+owK5L3Fk= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727043AbgIUMoZ (ORCPT ); Mon, 21 Sep 2020 08:44:25 -0400 Received: from mail.kernel.org ([198.145.29.99]:54584 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727001AbgIUMoO (ORCPT ); Mon, 21 Sep 2020 08:44:14 -0400 Received: from lenoir.home (lfbn-ncy-1-588-162.w81-51.abo.wanadoo.fr [81.51.203.162]) (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 1A1CC222BB; Mon, 21 Sep 2020 12:44:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600692254; bh=iSQLytuvoTVSkVFQJBym4elXGfzuYLVgReaXc9VqAPw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=GX+m1v5R4v7md0gi81mfNEKZZ4idp+KVP5+LZuddvagaWs2lCERWOHhng8wxeqo3s fTwLykGfTsjHvuwbzvRIv34PKfTCv2VSBaJbCq2fCBX70ntyoXLQmXE78iGW9ZW+wa d3HqKZih0xoq5P0kY6jqNyKIFbuoHoCk1ovFpSuY= From: Frederic Weisbecker To: "Paul E . McKenney" Cc: LKML , Frederic Weisbecker , Steven Rostedt , Mathieu Desnoyers , Lai Jiangshan , Joel Fernandes , Josh Triplett Subject: [RFC PATCH 08/12] rcu: Flush bypass before setting SEGCBLIST_SOFTIRQ_ONLY Date: Mon, 21 Sep 2020 14:43:47 +0200 Message-Id: <20200921124351.24035-9-frederic@kernel.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200921124351.24035-1-frederic@kernel.org> References: <20200921124351.24035-1-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 --- kernel/rcu/tree_plugin.h | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h index 3361bd351f3b..cee15841c178 100644 --- a/kernel/rcu/tree_plugin.h +++ b/kernel/rcu/tree_plugin.h @@ -2302,11 +2302,17 @@ static void __rcu_nocb_rdp_deoffload(struct rcu_data *rdp) !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); } static long rcu_nocb_rdp_deoffload(void *arg) -- 2.28.0