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=-13.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,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 898EBC2D0A3 for ; Tue, 10 Nov 2020 00:56:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 350B9206D8 for ; Tue, 10 Nov 2020 00:56:42 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="DiXIGqNl" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730387AbgKJA4k (ORCPT ); Mon, 9 Nov 2020 19:56:40 -0500 Received: from mail.kernel.org ([198.145.29.99]:54382 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731372AbgKJA4g (ORCPT ); Mon, 9 Nov 2020 19:56:36 -0500 Received: from localhost.localdomain (i15-lef02-th2-89-83-252-17.ft.lns.abo.bbox.fr [89.83.252.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id CAB1120870; Tue, 10 Nov 2020 00:56:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1604969795; bh=uJeon2zP9TBqtmay/pfkSlutJH7LXMfUFLS1zmgCfCw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=DiXIGqNlaZ4jP0kWSj2kE2Pq7BKGtFOaNzstZ9ZBmvoE1HAlKIkzdAOZ6yFzud8gM YlqZFNSjTxIURNnk71Uv1x46MeHLjsxFE1T6jg2hKvwDgCaC3DClT4tJCOY7Ezi2UH U3H+bEb1ZhLpyYePi4A11gWTb67CyZPgUTC7/yhs= 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 7/7] preempt/dynamic: Support dynamic preempt with preempt= boot option Date: Tue, 10 Nov 2020 01:56:09 +0100 Message-Id: <20201110005609.40989-8-frederic@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20201110005609.40989-1-frederic@kernel.org> References: <20201110005609.40989-1-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)" Support the preempt= boot option and patch the static call sites accordingly. Signed-off-by: Peter Zijlstra (Intel) Cc: Thomas Gleixner Cc: Mel Gorman Cc: Ingo Molnar Cc: Michal Hocko Cc: Paul E. McKenney [remove the mad scientist experiments] Signed-off-by: Frederic Weisbecker --- kernel/sched/core.c | 67 ++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 66 insertions(+), 1 deletion(-) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 6715caa17ea7..84ac05d2df3a 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -12,6 +12,7 @@ #include "sched.h" +#include #include #include @@ -4772,9 +4773,73 @@ DEFINE_STATIC_CALL(preempt_schedule_notrace, __preempt_schedule_notrace_func()); EXPORT_STATIC_CALL(preempt_schedule_notrace); #endif - #endif /* CONFIG_PREEMPTION */ +#ifdef CONFIG_PREEMPT_DYNAMIC + +/* + * SC:cond_resched + * SC:might_resched + * SC:preempt_schedule + * SC:preempt_schedule_notrace + * SC:irqentry_exit_cond_resched + * + * + * NONE: + * cond_resched <- __cond_resched + * might_resched <- RET0 + * preempt_schedule <- NOP + * preempt_schedule_notrace <- NOP + * irqentry_exit_cond_resched <- NOP + * + * VOLUNTARY: + * cond_resched <- __cond_resched + * might_resched <- __cond_resched + * preempt_schedule <- NOP + * preempt_schedule_notrace <- NOP + * irqentry_exit_cond_resched <- NOP + * + * FULL: + * cond_resched <- RET0 + * might_resched <- RET0 + * preempt_schedule <- preempt_schedule + * preempt_schedule_notrace <- preempt_schedule_notrace + * irqentry_exit_cond_resched <- irqentry_exit_cond_resched + */ +static int __init setup_preempt_mode(char *str) +{ + if (!strcmp(str, "none")) { + static_call_update(cond_resched, __cond_resched); + static_call_update(might_resched, __static_call_return0); + static_call_update(preempt_schedule, (typeof(&preempt_schedule)) NULL); + static_call_update(preempt_schedule_notrace, (typeof(&preempt_schedule_notrace)) NULL); + static_call_update(irqentry_exit_cond_resched, (typeof(&irqentry_exit_cond_resched)) NULL); + pr_info("Dynamic Preempt: %s\n", str); + } else if (!strcmp(str, "voluntary")) { + static_call_update(cond_resched, __cond_resched); + static_call_update(might_resched, __cond_resched); + static_call_update(preempt_schedule, (typeof(&preempt_schedule)) NULL); + static_call_update(preempt_schedule_notrace, (typeof(&preempt_schedule_notrace)) NULL); + static_call_update(irqentry_exit_cond_resched, (typeof(&irqentry_exit_cond_resched)) NULL); + pr_info("Dynamic Preempt: %s\n", str); + } else if (!strcmp(str, "full")) { + static_call_update(cond_resched, __static_call_return0); + static_call_update(might_resched, __static_call_return0); + static_call_update(preempt_schedule, __preempt_schedule_func()); + static_call_update(preempt_schedule_notrace, __preempt_schedule_notrace_func()); + static_call_update(irqentry_exit_cond_resched, irqentry_exit_cond_resched); + pr_info("Dynamic Preempt: %s\n", str); + } else { + pr_warn("Dynamic Preempt: Unsupported preempt mode %s, default to full\n", str); + return 1; + } + return 0; +} +__setup("preempt=", setup_preempt_mode); + +#endif /* CONFIG_PREEMPT_DYNAMIC */ + + /* * This is the entry point to schedule() from kernel preemption * off of irq context. -- 2.25.1