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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1198AC433F5 for ; Fri, 8 Oct 2021 15:49:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D865860F6F for ; Fri, 8 Oct 2021 15:49:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243199AbhJHPvt (ORCPT ); Fri, 8 Oct 2021 11:51:49 -0400 Received: from mail.kernel.org ([198.145.29.99]:50190 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243027AbhJHPvp (ORCPT ); Fri, 8 Oct 2021 11:51:45 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 245AE60F6F; Fri, 8 Oct 2021 15:49:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1633708190; bh=JwrcRjJJdJytp6KMBRFuWFHxkJ4MwWSom/YHngd3OBo=; h=Date:From:To:Cc:Subject:Reply-To:References:In-Reply-To:From; b=IFXz+969ie11cbjyEQYnqRoCI8vZB/T5rQENTrueNOX+L46rJI6D9kCsSnUITLjfH LUFitPKSHsDKmeRhjJP5zL4IKR74BIbCgeUrQWwFj4BIci156QEc/5tZdG309HjsZq 0ve/rhAMNIBia1Tlx042zc0CZIEVIGERPAUJlXJXhvBZ5rei/8xhBsunATAdWnqitW evoGVK5IKGk/zQQo/QdUaUpa23cYpFtRzMIDBPpTnBFEybriiBBYbPeYRc5vljQkTO 4+cSbDOVTCajPR65W03Elavd0QshP9nATDEo9/LX0BmCK61W3a3uhDaLYBZ2rdhL0l RYmsBJWK+GWZQ== Received: by paulmck-ThinkPad-P17-Gen-1.home (Postfix, from userid 1000) id DE5CC5C0887; Fri, 8 Oct 2021 08:49:49 -0700 (PDT) Date: Fri, 8 Oct 2021 08:49:49 -0700 From: "Paul E. McKenney" To: Valentin Schneider Cc: Frederic Weisbecker , LKML , Sebastian Andrzej Siewior , Peter Zijlstra , Uladzislau Rezki , Thomas Gleixner , Boqun Feng , Neeraj Upadhyay , Josh Triplett , Joel Fernandes , rcu@vger.kernel.org Subject: Re: [PATCH 00/11] rcu: Make rcu_core() safe in PREEMPT_RT with NOCB + a few other fixes Message-ID: <20211008154949.GQ880162@paulmck-ThinkPad-P17-Gen-1> Reply-To: paulmck@kernel.org References: <20210929221012.228270-1-frederic@kernel.org> <87fstkmybc.mognet@arm.com> <87ee8vlill.mognet@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87ee8vlill.mognet@arm.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Oct 08, 2021 at 03:03:02PM +0100, Valentin Schneider wrote: > On 01/10/21 18:47, Valentin Schneider wrote: > > On 30/09/21 00:10, Frederic Weisbecker wrote: > >> PREEMPT_RT has made rcu_core() preemptible, making it unsafe against > >> concurrent NOCB (de-)offloading. > >> > >> Thomas suggested to drop the local_lock() based solution and simply > >> check the offloaded state while context looks safe but that's not > >> enough. Here is a bit of rework. > >> > >> git://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux-dynticks.git > >> rcu/rt > >> > >> HEAD: aac1c58961446c731f2e989bd822ca1fd2659bad > >> > >> Thanks, > >> Frederic > > > > FWIW I've had RCU torture with NOCB toggling running for half a day on my > > Arm Juno and nothing to report. I still need to rebase this on an -rt tree > > and give it a spin with CONFIG_PREEMPT_RT. > > Rebased on top of v5.15-rc4-rt7-rebase with Thomas' patch reverted and ran > the same thing under CONFIG_PREEMPT_RT, nothing seems to catch on fire, so: > > Tested-by: Valentin Schneider Thank you!!! Thanx, Paul