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=-8.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 E9EFFC433DF for ; Sun, 21 Jun 2020 19:50:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BE771208D5 for ; Sun, 21 Jun 2020 19:50:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1592769053; bh=sQvbvZtNC41Uuf34UfNxe7YlKtNvaxn2Hj0hrJb16ic=; h=Date:From:To:Cc:Subject:Reply-To:References:In-Reply-To:List-ID: From; b=SfXmtuPDgecI9eMZOxoaTUHQ7QfYj3IW+CkjL98+vYosejaZ9Mnyvr8pujft4gdhe u6haB3pV7NZbvL0hkZ7u2CyKrN+n9TanrxaR95iMCrE38gDbZRzTqM8Fsc818k0uzp WKtB+vNe/1g2nGR4ClzLuQUEsZItZKlZT5UiwtyU= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730541AbgFUTux (ORCPT ); Sun, 21 Jun 2020 15:50:53 -0400 Received: from mail.kernel.org ([198.145.29.99]:50434 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730375AbgFUTux (ORCPT ); Sun, 21 Jun 2020 15:50:53 -0400 Received: from paulmck-ThinkPad-P72.home (50-39-105-78.bvtn.or.frontiernet.net [50.39.105.78]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 0AEBF2084D; Sun, 21 Jun 2020 19:50:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1592769053; bh=sQvbvZtNC41Uuf34UfNxe7YlKtNvaxn2Hj0hrJb16ic=; h=Date:From:To:Cc:Subject:Reply-To:References:In-Reply-To:From; b=cmannopnDOv4qkWaLIh5ai4GyQfnki8cosLeS6bTsQEeop4e6/Q6PvC55laeVbAEj ptKHftYZfGPqgVW40mXxfy9nLWR2sh2B5l0N9YUZ+f+51P0sazlkRKGmXpQDhG9EMx Rryxct6z2W7jbBJWGG6hJfuBYNo/whgT5EzMHBPg= Received: by paulmck-ThinkPad-P72.home (Postfix, from userid 1000) id E32EA3522FD1; Sun, 21 Jun 2020 12:50:52 -0700 (PDT) Date: Sun, 21 Jun 2020 12:50:52 -0700 From: "Paul E. McKenney" To: Neeraj Upadhyay Cc: josh@joshtriplett.org, rostedt@goodmis.org, mathieu.desnoyers@efficios.com, jiangshanlai@gmail.com, joel@joelfernandes.org, rcu@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] rcu/tree: Force quiescent state on callback overload Message-ID: <20200621195052.GF9247@paulmck-ThinkPad-P72> Reply-To: paulmck@kernel.org References: <1592764647-2452-1-git-send-email-neeraju@codeaurora.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1592764647-2452-1-git-send-email-neeraju@codeaurora.org> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: rcu-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: rcu@vger.kernel.org On Mon, Jun 22, 2020 at 12:07:27AM +0530, Neeraj Upadhyay wrote: > On callback overload, we want to force quiescent state immediately, > for the first and second fqs. Enforce the same, by including > RCU_GP_FLAG_OVLD flag, in fqsstart check. > > Signed-off-by: Neeraj Upadhyay Good catch! But what did you do to verify that this change does the right thing? Thanx, Paul > --- > kernel/rcu/tree.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c > index d0988a1..6226bfb 100644 > --- a/kernel/rcu/tree.c > +++ b/kernel/rcu/tree.c > @@ -1865,7 +1865,7 @@ static void rcu_gp_fqs_loop(void) > break; > /* If time for quiescent-state forcing, do it. */ > if (!time_after(rcu_state.jiffies_force_qs, jiffies) || > - (gf & RCU_GP_FLAG_FQS)) { > + (gf & (RCU_GP_FLAG_FQS | RCU_GP_FLAG_OVLD))) { > trace_rcu_grace_period(rcu_state.name, rcu_state.gp_seq, > TPS("fqsstart")); > rcu_gp_fqs(first_gp_fqs); > -- > The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, > a Linux Foundation Collaborative Project >