From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 93CFE1CEADA for ; Thu, 10 Oct 2024 14:29:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728570582; cv=none; b=ZdsICFvPlXrbcJgREdCLvkkiXAoGdZ2oiqOJM6gvksqCyz9AojLQnb/p7cfFCFnVTiY5CwWLZotT2tZf8gK/UKeDiRFmphxPxGm2iI6qqGWV7a4Yhsu0FZtzo9K/9aZFBL7Ed4e5iouMdsd5FgxXBiU2VDRmNXz+676gImSSbPk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728570582; c=relaxed/simple; bh=rtlbjuzcADmgbrzhURitQkm8HfaRBDB1VunjDdEsWsA=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=YjU6PrlzvGPzdZ141UzbnZLzQWNYqC61aZQXS55x+s/DicJ9WNtw2IzWTfZszzTC9UqyYcKBYEPpHclM8ZFYgjxYMrLM8zySbZUoNIGpHAERu3tS6quDZYoUSTATbc6rCotXATqrrZEt3v08pyqFC8HUyGTO47WcdxMLnDG53hs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=qFE3ekTt; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="qFE3ekTt" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1B1CAC4CEC5; Thu, 10 Oct 2024 14:29:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1728570582; bh=rtlbjuzcADmgbrzhURitQkm8HfaRBDB1VunjDdEsWsA=; h=Date:From:To:Cc:Subject:Reply-To:References:In-Reply-To:From; b=qFE3ekTto8xRKdtmfwvET7PHIkCRbZsW2VecpjYcf5IXDatWqaelchyr+XPC2J0UZ vL8UrCfuNCbLVXGrojFzcvBN5uTa/h2Rlht94X4bjdmQIBAQLMmRr31rSfAaH58dfh huUz7ou+0csv+Pm5Rjv8iWkewhfrjAZlQfc6Q1wQxhpslz42ztdC+Gw3pD3GPYNLJo rwt8f0DVp0U6SLwbYQeVNBXKUVrs3h1rNyTcN80yrbOU+G9+ZHdaYwuBhTxIeGvqZK 5zRitQXTYqFqcteZClOY3Lr8xxdvqAZQV+w5+Tc2VkVY9G3g0iKIf1b3OhaZrJI65P Or7dTVJRfUOEA== Received: by paulmck-ThinkPad-P17-Gen-1.home (Postfix, from userid 1000) id BC01DCE08E5; Thu, 10 Oct 2024 07:29:41 -0700 (PDT) Date: Thu, 10 Oct 2024 07:29:41 -0700 From: "Paul E. McKenney" To: Peter Zijlstra Cc: Sebastian Andrzej Siewior , Ankur Arora , linux-kernel@vger.kernel.org, tglx@linutronix.de, mingo@kernel.org, juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, vschneid@redhat.com, frederic@kernel.org, efault@gmx.de Subject: Re: [PATCH 3/7] rcu: fix header guard for rcu_all_qs() Message-ID: <497e034a-ec03-4aac-ae15-aae1bf30d263@paulmck-laptop> Reply-To: paulmck@kernel.org References: <20241009165411.3426937-1-ankur.a.arora@oracle.com> <20241009165411.3426937-4-ankur.a.arora@oracle.com> <20241010064123.WJjDYegr@linutronix.de> <20241010081129.GB17263@noisy.programming.kicks-ass.net> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20241010081129.GB17263@noisy.programming.kicks-ass.net> On Thu, Oct 10, 2024 at 10:11:29AM +0200, Peter Zijlstra wrote: > On Thu, Oct 10, 2024 at 08:41:23AM +0200, Sebastian Andrzej Siewior wrote: > > On 2024-10-09 09:54:07 [-0700], Ankur Arora wrote: > > > rcu_all_qs() is defined for !CONFIG_PREEMPT_RCU but the declaration > > > is conditioned on CONFIG_PREEMPTION. > > > > > > With CONFIG_PREEMPT_LAZY, CONFIG_PREEMPTION=y does not imply > > > CONFIG_PREEMPT_RCU=y. > > > > From kernel/rcu/Kconfig: > > | config PREEMPT_RCU > > | bool > > | default y if PREEMPTION > > > > this looks like PREEMPT_RCU implies PREEMPTION. > > The point was to make PREEMPT_RCU=n possible even when PREEMPTION=y, > which is fine. Agreed! Thanx, Paul