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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 91F78C433EF for ; Wed, 10 Nov 2021 20:26:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7D18761178 for ; Wed, 10 Nov 2021 20:26:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232909AbhKJU3P (ORCPT ); Wed, 10 Nov 2021 15:29:15 -0500 Received: from foss.arm.com ([217.140.110.172]:50680 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232859AbhKJU2P (ORCPT ); Wed, 10 Nov 2021 15:28:15 -0500 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 88E0C1435; Wed, 10 Nov 2021 12:25:27 -0800 (PST) Received: from e113632-lin.cambridge.arm.com (e113632-lin.cambridge.arm.com [10.1.196.57]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 5863A3F5A1; Wed, 10 Nov 2021 12:25:25 -0800 (PST) From: Valentin Schneider To: linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com, linuxppc-dev@lists.ozlabs.org, linux-kbuild@vger.kernel.org Cc: Marco Elver , Peter Zijlstra , Ingo Molnar , Frederic Weisbecker , Mike Galbraith , Dmitry Vyukov , Michael Ellerman , Benjamin Herrenschmidt , Paul Mackerras , Steven Rostedt , Masahiro Yamada , Michal Marek , Nick Desaulniers Subject: [PATCH v2 2/5] preempt/dynamic: Introduce preempt mode accessors Date: Wed, 10 Nov 2021 20:24:45 +0000 Message-Id: <20211110202448.4054153-3-valentin.schneider@arm.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20211110202448.4054153-1-valentin.schneider@arm.com> References: <20211110202448.4054153-1-valentin.schneider@arm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org CONFIG_PREEMPT{_NONE, _VOLUNTARY} designate either: o The build-time preemption model when !PREEMPT_DYNAMIC o The default boot-time preemption model when PREEMPT_DYNAMIC IOW, using those on PREEMPT_DYNAMIC kernels is meaningless - the actual model could have been set to something else by the "preempt=foo" cmdline parameter. Introduce a set of helpers to determine the actual preemption mode used by the live kernel. Suggested-by: Marco Elver Signed-off-by: Valentin Schneider --- include/linux/sched.h | 16 ++++++++++++++++ kernel/sched/core.c | 11 +++++++++++ 2 files changed, 27 insertions(+) diff --git a/include/linux/sched.h b/include/linux/sched.h index 5f8db54226af..0640d5622496 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -2073,6 +2073,22 @@ static inline void cond_resched_rcu(void) #endif } +#ifdef CONFIG_PREEMPT_DYNAMIC + +extern bool is_preempt_none(void); +extern bool is_preempt_voluntary(void); +extern bool is_preempt_full(void); + +#else + +#define is_preempt_none() IS_ENABLED(CONFIG_PREEMPT_NONE) +#define is_preempt_voluntary() IS_ENABLED(CONFIG_PREEMPT_VOLUNTARY) +#define is_preempt_full() IS_ENABLED(CONFIG_PREEMPT) + +#endif + +#define is_preempt_rt() IS_ENABLED(CONFIG_PREEMPT_RT) + /* * Does a critical section need to be broken due to another * task waiting?: (technically does not depend on CONFIG_PREEMPTION, diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 97047aa7b6c2..9db7f77e53c3 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -6638,6 +6638,17 @@ static void __init preempt_dynamic_init(void) } } +#define PREEMPT_MODE_ACCESSOR(mode) \ + bool is_preempt_##mode(void) \ + { \ + WARN_ON_ONCE(preempt_dynamic_mode == preempt_dynamic_undefined); \ + return preempt_dynamic_mode == preempt_dynamic_##mode; \ + } + +PREEMPT_MODE_ACCESSOR(none) +PREEMPT_MODE_ACCESSOR(voluntary) +PREEMPT_MODE_ACCESSOR(full) + #else /* !CONFIG_PREEMPT_DYNAMIC */ static inline void preempt_dynamic_init(void) { } -- 2.25.1