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=-19.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 32A4FC433E0 for ; Mon, 18 Jan 2021 14:16:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EBC2E22B39 for ; Mon, 18 Jan 2021 14:16:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2392753AbhAROQN (ORCPT ); Mon, 18 Jan 2021 09:16:13 -0500 Received: from mail.kernel.org ([198.145.29.99]:42556 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2392732AbhARON4 (ORCPT ); Mon, 18 Jan 2021 09:13:56 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 701E622C9D; Mon, 18 Jan 2021 14:12:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1610979161; bh=1cAkqJEmvE+Ld0yQposc40r3ymfj/fgFEzm9JOq8VCM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=KRXjaYuWcY8xlbLNhULUrqDG/j4qaOohRik+7wJVfgeWHeb84r/WHILvOWlqP00E6 1FbVrc5tFcZ2YFXSQkl1WW90HG0CoTm/D6nEsjG/GwDAsvwsE51YCwZxsC0cNSs4Tu TtI6wTJ3ls7YjcQVY3UXuxG6jO5fr6p74o6OcgtK/iZ7B3CZ7pO9BP0mk4UnWhfFbq znZ2nnFWoQMBXqCTJkXpGslXbOPPTLIuOR11Tg+ocGOw9LHyqABoHIzk51Tt+pYmkb bq+dWDJkHQ6U2a/UntrgXgz3mALa+xVsJb6y/9lqKbUatzBXb6AwdYV3iN1+tGP7as LYo3xoon3280Q== From: Frederic Weisbecker To: Peter Zijlstra Cc: LKML , Mel Gorman , Michal Hocko , Frederic Weisbecker , Thomas Gleixner , "Paul E . McKenney" , Ingo Molnar , Michal Hocko Subject: [RFC PATCH 5/8] preempt/dynamic: Provide cond_resched() and might_resched() static calls Date: Mon, 18 Jan 2021 15:12:20 +0100 Message-Id: <20210118141223.123667-6-frederic@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20210118141223.123667-1-frederic@kernel.org> References: <20210118141223.123667-1-frederic@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: "Peter Zijlstra (Intel)" Provide static calls to control cond_resched() (called in !CONFIG_PREEMPT) and might_resched() (called in CONFIG_PREEMPT_VOLUNTARY) to that we can override their behaviour when preempt= is overriden. Since the default behaviour is full preemption, both their calls are ignored when preempt= isn't passed. Signed-off-by: Peter Zijlstra (Intel) Cc: Thomas Gleixner Cc: Mel Gorman Cc: Ingo Molnar Cc: Michal Hocko Cc: Paul E. McKenney [branch might_resched() directly to __cond_resched(), only define static calls when PREEMPT_DYNAMIC] Signed-off-by: Frederic Weisbecker --- include/linux/kernel.h | 23 +++++++++++++++++++---- include/linux/sched.h | 27 ++++++++++++++++++++++++--- kernel/sched/core.c | 16 +++++++++++++--- 3 files changed, 56 insertions(+), 10 deletions(-) diff --git a/include/linux/kernel.h b/include/linux/kernel.h index f7902d8c1048..cfd3d349f905 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -15,7 +15,7 @@ #include #include #include - +#include #include #include @@ -81,11 +81,26 @@ struct pt_regs; struct user; #ifdef CONFIG_PREEMPT_VOLUNTARY -extern int _cond_resched(void); -# define might_resched() _cond_resched() + +extern int __cond_resched(void); +# define might_resched() __cond_resched() + +#elif defined(CONFIG_PREEMPT_DYNAMIC) + +extern int __cond_resched(void); + +DECLARE_STATIC_CALL(might_resched, __cond_resched); + +static __always_inline void might_resched(void) +{ + static_call(might_resched)(); +} + #else + # define might_resched() do { } while (0) -#endif + +#endif /* CONFIG_PREEMPT_* */ #ifdef CONFIG_DEBUG_ATOMIC_SLEEP extern void ___might_sleep(const char *file, int line, int preempt_offset); diff --git a/include/linux/sched.h b/include/linux/sched.h index 6e3a5eeec509..86bcb589da09 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1871,11 +1871,32 @@ static inline int test_tsk_need_resched(struct task_struct *tsk) * value indicates whether a reschedule was done in fact. * cond_resched_lock() will drop the spinlock before scheduling, */ -#ifndef CONFIG_PREEMPTION -extern int _cond_resched(void); +#if !defined(CONFIG_PREEMPTION) || defined(CONFIG_PREEMPT_DYNAMIC) +extern int __cond_resched(void); + +#ifdef CONFIG_PREEMPT_DYNAMIC + +DECLARE_STATIC_CALL(cond_resched, __cond_resched); + +static __always_inline int _cond_resched(void) +{ + return static_call(cond_resched)(); +} + #else + +static inline int _cond_resched(void) +{ + return __cond_resched(); +} + +#endif /* CONFIG_PREEMPT_DYNAMIC */ + +#else + static inline int _cond_resched(void) { return 0; } -#endif + +#endif /* !defined(CONFIG_PREEMPTION) || defined(CONFIG_PREEMPT_DYNAMIC) */ #define cond_resched() ({ \ ___might_sleep(__FILE__, __LINE__, 0); \ diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 15d2562118d1..d6de12b4eef2 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -6654,17 +6654,27 @@ SYSCALL_DEFINE0(sched_yield) return 0; } -#ifndef CONFIG_PREEMPTION -int __sched _cond_resched(void) +#if !defined(CONFIG_PREEMPTION) || defined(CONFIG_PREEMPT_DYNAMIC) +int __sched __cond_resched(void) { if (should_resched(0)) { preempt_schedule_common(); return 1; } +#ifndef CONFIG_PREEMPT_RCU rcu_all_qs(); +#endif return 0; } -EXPORT_SYMBOL(_cond_resched); +EXPORT_SYMBOL(__cond_resched); +#endif + +#ifdef CONFIG_PREEMPT_DYNAMIC +DEFINE_STATIC_CALL_RET0(cond_resched, __cond_resched); +EXPORT_STATIC_CALL(cond_resched); + +DEFINE_STATIC_CALL_RET0(might_resched, __cond_resched); +EXPORT_STATIC_CALL(might_resched); #endif /* -- 2.25.1