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 2496BC43381 for ; Wed, 6 Jan 2021 04:51:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EFF4122CE3 for ; Wed, 6 Jan 2021 04:51:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727310AbhAFEvW (ORCPT ); Tue, 5 Jan 2021 23:51:22 -0500 Received: from mail.kernel.org ([198.145.29.99]:33376 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726791AbhAFEuR (ORCPT ); Tue, 5 Jan 2021 23:50:17 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id DD862230FE; 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=1609908537; bh=4N/ttNNejpsHl6sFyhRfALMQ7Vl3QKfj945XUGPFMaA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=W9QpSS64Ko5SeN3Ta8jJtsoDq0TvmLq5pJddrrB8+jikQ42e2L94cxm4fGVsUBx3+ +FUzJsx69+LUs5R+WyIHjy7FGFotEV5nLmiTPb7vyBRSZ6zN3KSh8fZQUcOGPINjEh jI4sIMRYmbRasDQayPzGWzxSU0hbzZtCB01NSu8cw1yNm+OBUldN7HiwT61hOJHXRm sxxgvlbOFaaZkfqIKqUEIRQ318UX4vSsdqaIVibrCcrqpt3u1mNzWjOZLBHp2Wnm6d ggep5H1EduyAzGCbjaQyF0O34Mk0Ity3rOM6CzwjkLOsQjOr9MrEQMqdcGvqzR2Ijc yO5pyo1phHC3Q== 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 10/21] rcu/nocb: Set SEGCBLIST_SOFTIRQ_ONLY at the very last stage of de-offloading Date: Tue, 5 Jan 2021 20:48:42 -0800 Message-Id: <20210106044853.20812-10-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 sets SEGCBLIST_SOFTIRQ_ONLY once toggling is otherwise fully complete, allowing further RCU callback manipulation to be carried out locklessly and locally. 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 | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h index 35dc9b3..8641b72 100644 --- a/kernel/rcu/tree_plugin.h +++ b/kernel/rcu/tree_plugin.h @@ -2352,7 +2352,14 @@ static int __rcu_nocb_rdp_deoffload(struct rcu_data *rdp) */ rcu_nocb_lock_irqsave(rdp, flags); 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); return ret; } -- 2.9.5