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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2F151C433FE for ; Thu, 20 Oct 2022 16:35:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230090AbiJTQfZ (ORCPT ); Thu, 20 Oct 2022 12:35:25 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39302 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230139AbiJTQfU (ORCPT ); Thu, 20 Oct 2022 12:35:20 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 631EA12A346; Thu, 20 Oct 2022 09:35:11 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id D9D47B826C4; Thu, 20 Oct 2022 16:35:04 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 84C10C433D6; Thu, 20 Oct 2022 16:35:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1666283703; bh=1D50o0naBc2gRDAfGm82dEQ7o6F3FtNqy0eWFByAG7M=; h=Date:From:To:Cc:Subject:Reply-To:References:In-Reply-To:From; b=JJgVs/jKQbha1MJ/tMXRUd38n/8JTRLH+incUHDo585lwYHRAA6HCxLmU+XWNsA/P O9MlU3/sW93OUer5A0lh61+uX7y8HzkYAF8X28Ezi7qmmCT4HeR69+NZTS+sG2RrPq 7ZodZ5+qo3R0IA7QIDDqBAG9ALtgH2uCX67JwZpuYFoiKJheECrHlbMzkPvQHtQ+6o jNUoIBkKzkJA4jxIcJIsk+y4y24gDDvqAB/nYS6s/K8sXFCvveK6esE89jutTyMAEQ RWEDcP5BEzU16xhGxoY+WMA1JnzrfSi7lp/2n+YOyug/biSIVB5xVkIFLy0tMS4nbg Te8MCGbG6KCjg== Received: by paulmck-ThinkPad-P17-Gen-1.home (Postfix, from userid 1000) id 2BF0C5C04D0; Thu, 20 Oct 2022 09:35:03 -0700 (PDT) Date: Thu, 20 Oct 2022 09:35:03 -0700 From: "Paul E. McKenney" To: Heiko Carstens Cc: Christian Borntraeger , rcu@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-team@fb.com, rostedt@goodmis.org, Neeraj Upadhyay , Frederic Weisbecker , Boqun Feng , Vasily Gorbik , Alexander Gordeev , Sven Schnelle , Thomas Gleixner , John Ogness , Petr Mladek , linux-s390@vger.kernel.org Subject: Re: [PATCH v3 rcu 08/11] arch/s390: Add ARCH_HAS_NMI_SAFE_THIS_CPU_OPS Kconfig option Message-ID: <20221020163503.GQ5600@paulmck-ThinkPad-P17-Gen-1> Reply-To: paulmck@kernel.org References: <20221019225838.GA2500612@paulmck-ThinkPad-P17-Gen-1> <20221019225846.2501109-8-paulmck@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Oct 20, 2022 at 09:27:37AM +0200, Heiko Carstens wrote: > On Thu, Oct 20, 2022 at 09:23:49AM +0200, Heiko Carstens wrote: > > On Thu, Oct 20, 2022 at 07:16:44AM +0200, Christian Borntraeger wrote: > > > Am 20.10.22 um 00:58 schrieb Paul E. McKenney: > > > > The s390 architecture uses either a cmpxchg loop (old systems) > > > > or the laa add-to-memory instruction (new systems) to implement > > > > this_cpu_add(), both of which are NMI safe. This means that the old > > > > and more-efficient srcu_read_lock() may be used in NMI context, without > > > > the need for srcu_read_lock_nmisafe(). Therefore, add the new Kconfig > > > > option ARCH_HAS_NMI_SAFE_THIS_CPU_OPS to arch/arm64/Kconfig, which will > > > s390 ? > > Ah, this typo is what Christian pointed out; missed that. > > > > > cause NEED_SRCU_NMI_SAFE to be deselected, thus preserving the current > > > > srcu_read_lock() behavior. > > > > > > > > Link: https://lore.kernel.org/all/20220910221947.171557773@linutronix.de/ > > > > > > > > Suggested-by: Neeraj Upadhyay > > > > Suggested-by: Frederic Weisbecker > > > > Suggested-by: Boqun Feng > > > > Signed-off-by: Paul E. McKenney > > ... > > > > --- > > > > arch/s390/Kconfig | 1 + > > > > 1 file changed, 1 insertion(+) > > > > Not sure what Christian was trying to say with his empty reply :) > > In any case: > > Acked-by: Heiko Carstens I will apply the fix and the ack on my next rebase, thank you both! Thanx, Paul