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=-19.7 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=unavailable 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 48204C43460 for ; Tue, 11 May 2021 23:09:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 209096192B for ; Tue, 11 May 2021 23:09:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230384AbhEKXK4 (ORCPT ); Tue, 11 May 2021 19:10:56 -0400 Received: from mail.kernel.org ([198.145.29.99]:46722 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229934AbhEKXKv (ORCPT ); Tue, 11 May 2021 19:10:51 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id B6C8D61919; Tue, 11 May 2021 23:09:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1620774584; bh=MM0CqeSkHwAV3YroUCw4vgYKKdVO10PGjsqK32KIwy4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=m+WcdkcUve8Uiw+3kZgnsUjAZqrflGb71NoTEKKRQTGMRJb/TVAU+GpoV8jFt7hpi 7Pp9ldTXKWaQdAvGIWPp7cn3OKeTsAG2pQ29zCYPMLLetmE8H9A7hmdZEYUCWFCw0e z+Qk2+xQp0lqubqFTbhn5tdm0wGnZynIYQijD/pAbV44F5cAuItvOvro5rsWfFOvw8 zssO5MXhIeaLmzsLOcfrm2qsvpXPN2R73YXcad5JxsWYEAwpzG/pId8tdnPeF2AZs4 2CZdlugMrU2VGqn8RC16HbcYQ/rq0WwFFeMlOuWvHeGcRpFsPT9MOj1+X28l2C9yzq cWuD6DRMq71/w== Received: by paulmck-ThinkPad-P17-Gen-1.home (Postfix, from userid 1000) id 56B2D5C09EF; Tue, 11 May 2021 16:09:44 -0700 (PDT) From: "Paul E. McKenney" 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, "Paul E. McKenney" , =?UTF-8?q?Toke=20H=C3=B8iland-J=C3=B8rgensen?= , Masami Hiramatsu Subject: [PATCH tip/core/rcu 3/4] rcu-tasks: Make ksoftirqd provide RCU Tasks quiescent states Date: Tue, 11 May 2021 16:09:41 -0700 Message-Id: <20210511230942.2894861-3-paulmck@kernel.org> X-Mailer: git-send-email 2.31.1.189.g2e36527f23 In-Reply-To: <20210511230720.GA2894512@paulmck-ThinkPad-P17-Gen-1> References: <20210511230720.GA2894512@paulmck-ThinkPad-P17-Gen-1> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Heavy networking load can cause a CPU to execute continuously and indefinitely within ksoftirqd, in which case there will be no voluntary task switches and thus no RCU-tasks quiescent states. This commit therefore causes the exiting rcu_softirq_qs() to provide an RCU-tasks quiescent state. This of course means that __do_softirq() and its callers cannot be invoked from within a tracing trampoline. Reported-by: Toke Høiland-Jørgensen Tested-by: Toke Høiland-Jørgensen Signed-off-by: Paul E. McKenney Cc: Steven Rostedt Cc: Masami Hiramatsu --- kernel/rcu/tree.c | 1 + 1 file changed, 1 insertion(+) diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 8e78b2430c16..f4daa4e60b14 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -242,6 +242,7 @@ void rcu_softirq_qs(void) { rcu_qs(); rcu_preempt_deferred_qs(current); + rcu_tasks_qs(current, false); } /* -- 2.31.1.189.g2e36527f23