From nobody Wed Sep 10 09:23:41 2025 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7B3ECC04A6A for ; Tue, 1 Aug 2023 21:25:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232279AbjHAVZT (ORCPT ); Tue, 1 Aug 2023 17:25:19 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44438 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232272AbjHAVYz (ORCPT ); Tue, 1 Aug 2023 17:24:55 -0400 Received: from desiato.infradead.org (desiato.infradead.org [IPv6:2001:8b0:10b:1:d65d:64ff:fe57:4e05]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 62DC135AA for ; Tue, 1 Aug 2023 14:24:31 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=Content-Type:MIME-Version:References: Subject:Cc:To:From:Date:Message-ID:Sender:Reply-To:Content-Transfer-Encoding: Content-ID:Content-Description:In-Reply-To; bh=q92jsVFPZSP8G7FOeDp8TiMSNcZFRY9w1smIqAIutpc=; b=Zs/CXT4SulTjrAAiY5k/JWkVbm nhCxY6+yMoC+VlPJZokF8S4WA4fqGlAOTXENgeCoeHlkKzuq0wipZHItvz0AG72ro+VhW3Rlw8Fy+ ElTqg9gWrlTzSzFSOHOjUXPVGaa4AsavKRfIAD17HosObUFW+rCfubbLhI/BsR7UiLTr3ExI55yRp T0wjF+UVz+E7tCmZssp6z135YlHwBTB0VPKI0UC8Z+JzCUVCktqH0bmCT1imWr3KQA7lvam5+LWJT mWBpEaT7XJ96fmYyMKMQdX53gcJGDStd6CGGK0Ni5ERXhsLs7R/SAuGQH379LjysbNS7AvlYS07Iz M3/Z86xw==; Received: from j130084.upc-j.chello.nl ([24.132.130.84] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.96 #2 (Red Hat Linux)) id 1qQwqn-00EvTw-1h; Tue, 01 Aug 2023 21:24:19 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id BEE5930310E; Tue, 1 Aug 2023 23:24:15 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 0) id 52AE820283BA4; Tue, 1 Aug 2023 23:24:15 +0200 (CEST) Message-ID: <20230801211812.236247952@infradead.org> User-Agent: quilt/0.66 Date: Tue, 01 Aug 2023 22:41:28 +0200 From: Peter Zijlstra To: mingo@redhat.com Cc: peterz@infradead.org, juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, bristot@redhat.com, vschneid@redhat.com, linux-kernel@vger.kernel.org Subject: [PATCH 7/9] sched: Simplify sched_tick_remote() References: <20230801204121.929256934@infradead.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Use guards to reduce gotos and simplify control flow. Signed-off-by: Peter Zijlstra (Intel) --- kernel/sched/core.c | 43 ++++++++++++++++++------------------------- 1 file changed, 18 insertions(+), 25 deletions(-) --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -5651,9 +5651,6 @@ static void sched_tick_remote(struct wor struct tick_work *twork =3D container_of(dwork, struct tick_work, work); int cpu =3D twork->cpu; struct rq *rq =3D cpu_rq(cpu); - struct task_struct *curr; - struct rq_flags rf; - u64 delta; int os; =20 /* @@ -5663,30 +5660,26 @@ static void sched_tick_remote(struct wor * statistics and checks timeslices in a time-independent way, regardless * of when exactly it is running. */ - if (!tick_nohz_tick_stopped_cpu(cpu)) - goto out_requeue; + if (tick_nohz_tick_stopped_cpu(cpu)) { + guard(rq_lock_irq)(rq); + struct task_struct *curr =3D rq->curr; + + if (cpu_online(cpu)) { + update_rq_clock(rq); + + if (!is_idle_task(curr)) { + /* + * Make sure the next tick runs within a + * reasonable amount of time. + */ + u64 delta =3D rq_clock_task(rq) - curr->se.exec_start; + WARN_ON_ONCE(delta > (u64)NSEC_PER_SEC * 3); + } + curr->sched_class->task_tick(rq, curr, 0); =20 - rq_lock_irq(rq, &rf); - curr =3D rq->curr; - if (cpu_is_offline(cpu)) - goto out_unlock; - - update_rq_clock(rq); - - if (!is_idle_task(curr)) { - /* - * Make sure the next tick runs within a reasonable - * amount of time. - */ - delta =3D rq_clock_task(rq) - curr->se.exec_start; - WARN_ON_ONCE(delta > (u64)NSEC_PER_SEC * 3); + calc_load_nohz_remote(rq); + } } - curr->sched_class->task_tick(rq, curr, 0); - - calc_load_nohz_remote(rq); -out_unlock: - rq_unlock_irq(rq, &rf); -out_requeue: =20 /* * Run the remote tick once per second (1Hz). This arbitrary