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 63E32C433DB for ; Mon, 18 Jan 2021 14:18:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2A08422B39 for ; Mon, 18 Jan 2021 14:18:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2392802AbhAROPo (ORCPT ); Mon, 18 Jan 2021 09:15:44 -0500 Received: from mail.kernel.org ([198.145.29.99]:42560 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2392736AbhARON7 (ORCPT ); Mon, 18 Jan 2021 09:13:59 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 67C9F22CA1; Mon, 18 Jan 2021 14:12:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1610979168; bh=maOE0t2qCzLXXJa98F60rxAWTjZbx3uDnfqiP1D+1ys=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=HHTtHWWdAoXP2indwjIi65y5b0vSF9XU6CZyFyn0rUaFkdPBXGsFB8aVJlfwRfTWf m6TumGzwlbnNlljDGnGnicQSgaZOGn02ONgGG0mp2kAzPun+0WGNb2HM0tJO8gdwav X6KgV1K2DFTwp+HM+cX/eTEKlks58VZT6piZZvKYNCsLsqywQ4jj9OdnVY/mH0Q/n9 C9n9TZwsQuE3bl/qciwCinr9bdwDw9N3PGSOtCq2tqeZVGDCpGE/TdAcG3vNf4UXde 7cYt7bmMHtXtmVviMpuAHJ9mYqyfWaKHPsvMp2J3+Bxk64aeHqA1kTqhe30jWWMb/b msdSRe5kp4CBQ== 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 8/8] preempt/dynamic: Support dynamic preempt with preempt= boot option Date: Mon, 18 Jan 2021 15:12:23 +0100 Message-Id: <20210118141223.123667-9-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)" 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 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 faff4b546c5f..509bd51f59aa 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -12,6 +12,7 @@ #include "sched.h" +#include #include #include @@ -5314,9 +5315,73 @@ 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, (typeof(&__cond_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, (typeof(&__cond_resched)) __static_call_return0); + static_call_update(might_resched, (typeof(&__cond_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