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=-3.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no 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 93208C7618F for ; Tue, 16 Jul 2019 20:10:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 715CC2173C for ; Tue, 16 Jul 2019 20:10:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388705AbfGPUKt (ORCPT ); Tue, 16 Jul 2019 16:10:49 -0400 Received: from mx1.redhat.com ([209.132.183.28]:59722 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728575AbfGPUKs (ORCPT ); Tue, 16 Jul 2019 16:10:48 -0400 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 361C13082B6D; Tue, 16 Jul 2019 20:10:48 +0000 (UTC) Received: from torg (ovpn-122-28.rdu2.redhat.com [10.10.122.28]) by smtp.corp.redhat.com (Postfix) with ESMTP id 76D2C60C44; Tue, 16 Jul 2019 20:10:42 +0000 (UTC) Date: Tue, 16 Jul 2019 15:10:40 -0500 From: Clark Williams To: Thomas Gleixner Cc: Linus Torvalds , LKML , Andrew Morton , Greg Kroah-Hartman , Ingo Molnar , Peter Zijlstra , 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: <20190716151040.04ef9122@torg> In-Reply-To: <20190715150601.205143057@linutronix.de> References: <20190715150402.798499167@linutronix.de> <20190715150601.205143057@linutronix.de> Organization: Red Hat, Inc MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.45]); Tue, 16 Jul 2019 20:10:48 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 15 Jul 2019 17:04:03 +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 Excited to see this Thomas. Now I can start planning to build from a single tree rather than an RT tree off to the side of RHEL :) Acked-by: Clark Williams > --- > 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 > > -- The United States Coast Guard Ruining Natural Selection since 1790