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=-5.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,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 D5E4BC76192 for ; Wed, 17 Jul 2019 07:39:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A41D121743 for ; Wed, 17 Jul 2019 07:39:42 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="rjLQ3kgp" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726216AbfGQHjI (ORCPT ); Wed, 17 Jul 2019 03:39:08 -0400 Received: from merlin.infradead.org ([205.233.59.134]:34800 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725906AbfGQHjI (ORCPT ); Wed, 17 Jul 2019 03:39:08 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=merlin.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=J0DX3eo5YEZ7czByoiftQzjyznMsu/Ci0NQ1fe80Fhk=; b=rjLQ3kgp2imt9Tw8aCCls2UXV 8rm2o/GZHLT7HQtRFT3j/Jid7nIOOfPDdBgX+t3RitxkA+6m59gFHdn6j+/5VlXZw3qeIx+YG+Nmd R5OxzI3p1RAKYpdlvaJIyNHP5RrW08vQVA1K/ZB9FiatcAWB09TxLBx/UCNAwsQfOSjOBAJooiqhs uwf/XsndXJMUVtsaE8qYAJZo3JhalQudl9GVbex/IFOcyNwTUOQl9NTIMrv1V13hzqgFA9iI2MdEy v8DL73Y8VoL/G8tXUX7TVYdIA4UC+zgCVzkBI0KvSgmXPKnpzM3VnKznDw6BAUV5TOUHbgD/j/F1h wrQO+iQsw==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=hirez.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.92 #3 (Red Hat Linux)) id 1hneWB-0008Jf-1f; Wed, 17 Jul 2019 07:38:27 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 58BB92059DEA3; Wed, 17 Jul 2019 09:38:24 +0200 (CEST) Date: Wed, 17 Jul 2019 09:38:24 +0200 From: Peter Zijlstra To: Thomas Gleixner Cc: Linus Torvalds , LKML , Andrew Morton , Greg Kroah-Hartman , Ingo Molnar , Steven Rostedt , Sebastian Siewior , Paul McKenney , Christoph Hellwig , Tejun Heo , Lukas Bulwahn , Daniel Wagner , Tom Zanussi , Daniel Bristot de Oliveira , Clark Williams , Julia Cartwright , Marc Zyngier , Frederic Weisbecker Subject: Re: [patch 1/1] Kconfig: Introduce CONFIG_PREEMPT_RT Message-ID: <20190717073824.GT3419@hirez.programming.kicks-ass.net> References: <20190715150402.798499167@linutronix.de> <20190715150601.205143057@linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190715150601.205143057@linutronix.de> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jul 15, 2019 at 05:04:03PM +0200, Thomas Gleixner wrote: > Add a new entry to the preemption menu which enables the real-time support > for the kernel. The choice is only enabled when an architecture supports > it. > > It selects PREEMPT as the RT features depend on it. To achieve that the > existing PREEMPT choice is renamed to PREEMPT_LL which select PREEMPT as > well. > > No functional change. > > Signed-off-by: Thomas Gleixner Acked-by: Peter Zijlstra (Intel) > --- > arch/Kconfig | 3 +++ > kernel/Kconfig.preempt | 25 +++++++++++++++++++++++-- > 2 files changed, 26 insertions(+), 2 deletions(-) > > --- a/arch/Kconfig > +++ b/arch/Kconfig > @@ -809,6 +809,9 @@ config ARCH_NO_COHERENT_DMA_MMAP > config ARCH_NO_PREEMPT > bool > > +config ARCH_SUPPORTS_RT > + bool > + > config CPU_NO_EFFICIENT_FFS > def_bool n > > --- a/kernel/Kconfig.preempt > +++ b/kernel/Kconfig.preempt > @@ -35,10 +35,10 @@ config PREEMPT_VOLUNTARY > > Select this if you are building a kernel for a desktop system. > > -config PREEMPT > +config PREEMPT_LL > bool "Preemptible Kernel (Low-Latency Desktop)" > depends on !ARCH_NO_PREEMPT > - select PREEMPT_COUNT > + select PREEMPT > select UNINLINE_SPIN_UNLOCK if !ARCH_INLINE_SPIN_UNLOCK > help > This option reduces the latency of the kernel by making > @@ -55,7 +55,28 @@ config PREEMPT > embedded system with latency requirements in the milliseconds > range. > > +config PREEMPT_RT > + bool "Fully Preemptible Kernel (Real-Time)" > + depends on EXPERT && ARCH_SUPPORTS_RT > + select PREEMPT > + help > + This option turns the kernel into a real-time kernel by replacing > + various locking primitives (spinlocks, rwlocks, etc) with > + preemptible priority-inheritance aware variants, enforcing > + interrupt threading and introducing mechanisms to break up long > + non-preemtible sections. This makes the kernel, except for very > + low level and critical code pathes (entry code, scheduler, low > + level interrupt handling) fully preemtible and brings most > + execution contexts under scheduler control. > + > + Select this if you are building a kernel for systems which > + require real-time guarantees. > + > endchoice > > config PREEMPT_COUNT > bool > + > +config PREEMPT > + bool > + select PREEMPT_COUNT > >