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=-3.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,MALFORMED_FREEMAIL, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 DD753C7618F for ; Mon, 15 Jul 2019 19:47:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B2F7820659 for ; Mon, 15 Jul 2019 19:47:33 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="UCcm9G8C" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732207AbfGOTrc (ORCPT ); Mon, 15 Jul 2019 15:47:32 -0400 Received: from mail-wm1-f65.google.com ([209.85.128.65]:55855 "EHLO mail-wm1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730683AbfGOTrb (ORCPT ); Mon, 15 Jul 2019 15:47:31 -0400 Received: by mail-wm1-f65.google.com with SMTP id a15so16349180wmj.5 for ; Mon, 15 Jul 2019 12:47:29 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:date:to:cc:subject:in-reply-to:message-id:references :user-agent:mime-version; bh=oaprakcM0ZsBLgl1WvEc7yTP7kJj1QYuRyXuOP6H0s0=; b=UCcm9G8ClQRhN9otlsYaHWolKg9WD7Bd8Gnz7UUuvOw8AUf3+eza2zLYq1vq938kVB TCcafyovNuIiIdZfemn+yPWhI6mCqPu7GDZre892ubSvc98YV4hgWP7cB29zzJAfI9Ad mXfT2nYbqpw2hIy03yXiiipTWGlZ+3ZCmphI453L4OvyGju0EIAJg9W6ToYI2JLQSgf6 vON8JF7AdmqTlBgdng2ZrVFtsZyHeJbGO5U4yLjqrm6dKnk41z4GOt+PmsgPddb8ulN0 GM1+VigBvP7C4WIG0mEbWXiukWTEC1X/jmkOiGqqBV2I+z5DyrBlVB0S9gGu/BmC1TuJ 4SEQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:date:to:cc:subject:in-reply-to:message-id :references:user-agent:mime-version; bh=oaprakcM0ZsBLgl1WvEc7yTP7kJj1QYuRyXuOP6H0s0=; b=KCGS6O1BSvq98350KFVrFnnUkIFqnfiOo6XNdm9Um0dvzHBySc4b//J5NzMrMZNQat pFlXz7LNnTFhQPTZ+7chxLzMAXU2v/JsWzXJ2/hWEriIkZ3rPuIR0HXwaVHqFY3z/k7f O57/IbGTTam6HxRJvWheds8WNX9HvAh31MqrUdNUQoiChoXIepGR9qWb1o/E/CaqRhpg tVG7irgLSPD4AEj5qN42KhqRw7Vz//tqysepOq6psQDG0umZgk2eSwBvCsmJyfrQoSKk f12NMVYgAybeb0zXEhu6YgnSDE+4jFTW0splaE6GjWnSC6Fz8qVGlyqMJWbGKNzeXYse Ixjg== X-Gm-Message-State: APjAAAVtBwEXqcR9Ar5zcbEKqJC2O9RFR5NQIMg4SafIanlXR6dcJ2j0 aK+A+YDi08a1LJty+KlZE+E= X-Google-Smtp-Source: APXvYqycAln9pjBfy0nKk7M4yHfbZosdZAVfzy9a0t6b6joYjqdl9mv5ofnAcvjYD4jtFKDs2FTQAg== X-Received: by 2002:a7b:cf3a:: with SMTP id m26mr26794614wmg.6.1563220049215; Mon, 15 Jul 2019 12:47:29 -0700 (PDT) Received: from felia ([2001:16b8:2dc5:2000:cd36:d602:4f2d:7917]) by smtp.gmail.com with ESMTPSA id q1sm15229393wmq.25.2019.07.15.12.47.27 (version=TLS1_3 cipher=AEAD-AES256-GCM-SHA384 bits=256/256); Mon, 15 Jul 2019 12:47:28 -0700 (PDT) From: Lukas Bulwahn X-Google-Original-From: Lukas Bulwahn Date: Mon, 15 Jul 2019 21:47:27 +0200 (CEST) X-X-Sender: lukas@felia 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 In-Reply-To: <20190715150601.205143057@linutronix.de> Message-ID: References: <20190715150402.798499167@linutronix.de> <20190715150601.205143057@linutronix.de> User-Agent: Alpine 2.21 (DEB 202 2017-01-01) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 15 Jul 2019, 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 > --- > 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 Here is a typo: s/non-preemtible/non-preemptible/ Nice to see this feature finally getting very close to being merged :) Lukas > + 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 > > >