From nobody Mon Feb 9 15:26:13 2026 Received: from desiato.infradead.org (desiato.infradead.org [90.155.92.199]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BCD5B17B515 for ; Tue, 13 Aug 2024 22:50:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=90.155.92.199 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723589441; cv=none; b=e4sncx7u6cRtoQgTFRvKImLfNsSRtS4bYj1G2RE6CrYDHFuZqHQrjuS6KjStSfo8pKTAtWQzyeYN/ZiysBfny9dk7Q2WTlEQd8xFa6UUh/7x/JAuBGmYU3AcvbSs834wFdSgX9q71DdQW28IINe3vnLfQVOhMkeijhIoyfD0BFg= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723589441; c=relaxed/simple; bh=oVc9IqFKqy7QuIG8uxkR7uWuhN+j12qwydbAA7W7k00=; h=Message-Id:Date:From:To:Cc:Subject:References:MIME-Version: Content-Type; b=eo6bwcYrkhPMRCgbwKhVek3gjoiKbSXGxBq8B1hIzeT0MfcwZqbJ4KC3H1QKIBF7jHLO1O+IuLFtqMtux23uBRBL5+RZSLiZTaXRRyXlxRe3FFMnuDLfH9GaynsMNGJ9Ur0QJcVJuvsDB/MXhBfru+gAXyk/b4nXve0JYbPfB6U= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=OSSijcG0; arc=none smtp.client-ip=90.155.92.199 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="OSSijcG0" 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=LdwJUkU98p+KR13h+P1Cw+rkaPkvIEoyHv2nL1rKICw=; b=OSSijcG01R0yC0N4CYpxpyKazi GIgd0Ri5vIdc9iq+flh4mZFdwBrlxbi3Ue/gg8Zegqhs/gPlm4AewYodP/tI/eOQn5nlYMsWMP//U Oe8kbWZJrG9bm8uJTynM4nLmVc8J0kg/Ses3YCuluWHbgo56KnMLnmvStyuwT98/OMxsANGoQDwHV lX17GToXxFaCkX6fsmY1PgbOCHBs/vQXTq++ffAZeQ73svDJSruurfmMoZL9eFKjoCk0N+rQAbzK9 R0RHb1aZhlwgobBUBPVvCk6RyBGKqwoh+bjqdtocy7ktnzaPRV4eIzTCftS7URvPoA7s72MTG7FU6 ygDT5icA==; Received: from j130084.upc-j.chello.nl ([24.132.130.84] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.97.1 #2 (Red Hat Linux)) id 1se0LW-00000007s10-0hqd; Tue, 13 Aug 2024 22:50:30 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 0) id 348C3301195; Wed, 14 Aug 2024 00:50:29 +0200 (CEST) Message-Id: <20240813224015.724111109@infradead.org> User-Agent: quilt/0.65 Date: Wed, 14 Aug 2024 00:25:50 +0200 From: Peter Zijlstra To: mingo@kernel.org, tj@kernel.org, void@manifault.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, vschneid@redhat.com, linux-kernel@vger.kernel.org, joelaf@google.com Subject: [PATCH 2/9] sched: Fixup set_next_task() implementations References: <20240813222548.049744955@infradead.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" The rule is that: pick_next_task() :=3D pick_task() + set_next_task(.first =3D true) Turns out, there's still a few things in pick_next_task() that are missing from that combination. Signed-off-by: Peter Zijlstra (Intel) --- kernel/sched/deadline.c | 6 ++-- kernel/sched/fair.c | 62 ++++++++++++++++++++++++-------------------= ----- 2 files changed, 34 insertions(+), 34 deletions(-) --- a/kernel/sched/deadline.c +++ b/kernel/sched/deadline.c @@ -2392,6 +2392,9 @@ static void set_next_task_dl(struct rq * update_dl_rq_load_avg(rq_clock_pelt(rq), rq, 0); =20 deadline_queue_push_tasks(rq); + + if (hrtick_enabled(rq)) + start_hrtick_dl(rq, &p->dl); } =20 static struct sched_dl_entity *pick_next_dl_entity(struct dl_rq *dl_rq) @@ -2458,9 +2461,6 @@ static struct task_struct *pick_next_tas if (!p->dl_server) set_next_task_dl(rq, p, true); =20 - if (hrtick_enabled(rq)) - start_hrtick_dl(rq, &p->dl); - return p; } =20 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -8758,6 +8758,9 @@ static struct task_struct *pick_task_fai return task_of(se); } =20 +static void __set_next_task_fair(struct rq *rq, struct task_struct *p, boo= l first); +static void set_next_task_fair(struct rq *rq, struct task_struct *p, bool = first); + struct task_struct * pick_next_task_fair(struct rq *rq, struct task_struct *prev, struct rq_fla= gs *rf) { @@ -8806,33 +8809,17 @@ pick_next_task_fair(struct rq *rq, struc =20 put_prev_entity(cfs_rq, pse); set_next_entity(cfs_rq, se); + + __set_next_task_fair(rq, p, true); } =20 - goto done; + return p; + simple: #endif if (prev) put_prev_task(rq, prev); - - for_each_sched_entity(se) - set_next_entity(cfs_rq_of(se), se); - -done: __maybe_unused; -#ifdef CONFIG_SMP - /* - * Move the next running task to the front of - * the list, so our cfs_tasks list becomes MRU - * one. - */ - list_move(&p->se.group_node, &rq->cfs_tasks); -#endif - - if (hrtick_enabled_fair(rq)) - hrtick_start_fair(rq, p); - - update_misfit_status(p, rq); - sched_fair_update_stop_tick(rq, p); - + set_next_task_fair(rq, p, true); return p; =20 idle: @@ -13142,12 +13129,7 @@ static void switched_to_fair(struct rq * } } =20 -/* Account for a task changing its policy or group. - * - * This routine is mostly called to set cfs_rq->curr field when a task - * migrates between groups/classes. - */ -static void set_next_task_fair(struct rq *rq, struct task_struct *p, bool = first) +static void __set_next_task_fair(struct rq *rq, struct task_struct *p, boo= l first) { struct sched_entity *se =3D &p->se; =20 @@ -13160,6 +13142,27 @@ static void set_next_task_fair(struct rq list_move(&se->group_node, &rq->cfs_tasks); } #endif + if (!first) + return; + + SCHED_WARN_ON(se->sched_delayed); + + if (hrtick_enabled_fair(rq)) + hrtick_start_fair(rq, p); + + update_misfit_status(p, rq); + sched_fair_update_stop_tick(rq, p); +} + +/* + * Account for a task changing its policy or group. + * + * This routine is mostly called to set cfs_rq->curr field when a task + * migrates between groups/classes. + */ +static void set_next_task_fair(struct rq *rq, struct task_struct *p, bool = first) +{ + struct sched_entity *se =3D &p->se; =20 for_each_sched_entity(se) { struct cfs_rq *cfs_rq =3D cfs_rq_of(se); @@ -13169,10 +13172,7 @@ static void set_next_task_fair(struct rq account_cfs_rq_runtime(cfs_rq, 0); } =20 - if (!first) - return; - - SCHED_WARN_ON(se->sched_delayed); + __set_next_task_fair(rq, p, first); } =20 void init_cfs_rq(struct cfs_rq *cfs_rq)