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 D103BC43463 for ; Mon, 21 Sep 2020 12:44:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8B89C207BC for ; Mon, 21 Sep 2020 12:44:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600692273; bh=JmVHmlHA6JccXUGbRcmXBHQFl1BTEkaRwH2UiiQCbOk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=OCr9Xv4uIElPSz29PBdhmfjnb7DO0jrKsHLLxmKiIYjntX70UuQTVKE3PYibA47yC ecvHQ0uwEKFd+t0CF19KmEOqIDqKgNbR1r6lgmd9acVRUz21huQgRZTRrS2Hh+G0dO eqb/HzerA1TF5EjIPHaXXG/8Z3y3wSF1G3sSa0OY= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727089AbgIUMoc (ORCPT ); Mon, 21 Sep 2020 08:44:32 -0400 Received: from mail.kernel.org ([198.145.29.99]:54612 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726470AbgIUMoQ (ORCPT ); Mon, 21 Sep 2020 08:44:16 -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 F0BD021BE5; Mon, 21 Sep 2020 12:44:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600692256; bh=JmVHmlHA6JccXUGbRcmXBHQFl1BTEkaRwH2UiiQCbOk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=zvfZipf2WwpO7SwV3RQ6Z03/mKUJVCJmrrbyI1DKpYt2lQe4Hx/88Jyo85xptI9va JyDnhbeXkZe8YacYMPR7wGKZb1E2gMyOUl98UdrwXkYlYVld2Blp6XBjI6cMYLXxWO RawUDdZ311kunzRVJc2FrVEnYgSlrPSa77/zvic0= From: Frederic Weisbecker To: "Paul E . McKenney" Cc: LKML , Frederic Weisbecker , Steven Rostedt , Mathieu Desnoyers , Lai Jiangshan , Joel Fernandes , Josh Triplett Subject: [RFC PATCH 09/12] rcu: Set SEGCBLIST_SOFTIRQ_ONLY at the very last stage of de-offloading Date: Mon, 21 Sep 2020 14:43:48 +0200 Message-Id: <20200921124351.24035-10-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 Set SEGCBLIST_SOFTIRQ_ONLY once everything is settled. After that, the callbacks are handled locklessly and locally. 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 | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h index cee15841c178..ef09897c8f2c 100644 --- a/kernel/rcu/tree_plugin.h +++ b/kernel/rcu/tree_plugin.h @@ -2312,7 +2312,14 @@ static void __rcu_nocb_rdp_deoffload(struct rcu_data *rdp) * enqueued on bypass. */ rcu_nocb_flush_bypass(rdp, NULL, jiffies); - rcu_nocb_unlock_irqrestore(rdp, flags); + rcu_segcblist_set_flags(cblist, SEGCBLIST_SOFTIRQ_ONLY); + /* + * With SEGCBLIST_SOFTIRQ_ONLY, we can't use + * rcu_nocb_unlock_irqrestore() anymore. Theoretically we + * could set SEGCBLIST_SOFTIRQ_ONLY with cb unlocked and IRQs + * disabled now, but let's be paranoid. + */ + raw_spin_unlock_irqrestore(&rdp->nocb_lock, flags); } static long rcu_nocb_rdp_deoffload(void *arg) -- 2.28.0