From nobody Mon Feb 9 03:51:26 2026 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) (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 5E41E2110E; Sun, 18 Aug 2024 06:23:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=193.142.43.55 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723962197; cv=none; b=ce9Q+tTeaKSHbI5g9TgEaGRiDgeVu+/xOnMxUJx8bHuV9q01xmky003OBUgiTZtlE7oyDhBGtkCPxHTjGXjLwmn/MLtPKB/AyGEEcAG2pmbKnYQxxifEsEpqsjaFmqH9XdLhs41q2iVEA8zvIRa5GOmoqssZohmoz8+s3GmNyP0= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723962197; c=relaxed/simple; bh=EwlBHZ9gy5gta/7f+72x4UTsO9uGBs8EHhx9xTnb/PE=; h=Date:From:To:Subject:Cc:In-Reply-To:References:MIME-Version: Message-ID:Content-Type; b=a1JSH26QHJ/ogeYczQXGC0srEG30nDjSXpQnVNmdoMIiQEWji5MqShGFqZnhnNPDjUbeEKt88VtYyFOupAw7qx0IFdeEru84CSoMiXz7lvbMqHckQNFUn3zNzVH3icHtwk273LAq9b8TC+qy1tpQtS+bxh4B2XHAkRTBlOTaYco= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de; spf=pass smtp.mailfrom=linutronix.de; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=yIP36RyS; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=J5JqN0q7; arc=none smtp.client-ip=193.142.43.55 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linutronix.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="yIP36RyS"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="J5JqN0q7" Date: Sun, 18 Aug 2024 06:23:11 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1723962191; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=QCGGHQmEvsKZF0uh2UdAiJls5I5adendGg/FNQaGMM4=; b=yIP36RyS/wZqb6beLTaQE4db9dLKtoZSquIbYrzdnQOP5a613fn1gV0def/4neWzhwMBZx VMFlIlM6MLeQWvik+uYOedPfTSAnkoJ1fqDYNzDYcEbg7v5LKQH8xu+8FYBeWDLiV/P9+d OMF7UrvzRaAtQkYlCJxSliRMiOUepWwuZMWGRyjNVolsC0RLj3v4OQDcYVW/XG/ygtGBcH OQfFzvjgz8mkqhCVv3pDR8Vtx4ctsJis9sYtoRkXb/7TvP1SqVu2a7ZC5UzZ9I69XBmvtt AoNfoOf7/BgAfh8hf1lcBKs4QUHzZWe+Y7S7ClHqSvlPaQPj/r16Z6EyTX3Dhw== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1723962191; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=QCGGHQmEvsKZF0uh2UdAiJls5I5adendGg/FNQaGMM4=; b=J5JqN0q7VFCrD06MK+fJDnhtcX9fyXlUBqjsu5kThEanUaNnnZ2LnWss+17cxTNT1gmQ9G icASYPjSkLDaX/Cw== From: "tip-bot2 for Peter Zijlstra" Sender: tip-bot2@linutronix.de Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: sched/core] sched: Allow sched_class::dequeue_task() to fail Cc: "Peter Zijlstra (Intel)" , Valentin Schneider , x86@kernel.org, linux-kernel@vger.kernel.org In-Reply-To: <20240727105028.864630153@infradead.org> References: <20240727105028.864630153@infradead.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-ID: <172396219109.2215.13284109568756981039.tip-bot2@tip-bot2> Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Precedence: bulk Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable The following commit has been merged into the sched/core branch of tip: Commit-ID: 863ccdbb918a77e3f011571f943020bf7f0b114b Gitweb: https://git.kernel.org/tip/863ccdbb918a77e3f011571f943020bf7= f0b114b Author: Peter Zijlstra AuthorDate: Wed, 03 Apr 2024 09:50:20 +02:00 Committer: Peter Zijlstra CommitterDate: Sat, 17 Aug 2024 11:06:41 +02:00 sched: Allow sched_class::dequeue_task() to fail Change the function signature of sched_class::dequeue_task() to return a boolean, allowing future patches to 'fail' dequeue. Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Valentin Schneider Tested-by: Valentin Schneider Link: https://lkml.kernel.org/r/20240727105028.864630153@infradead.org --- kernel/sched/core.c | 7 +++++-- kernel/sched/deadline.c | 4 +++- kernel/sched/fair.c | 4 +++- kernel/sched/idle.c | 3 ++- kernel/sched/rt.c | 4 +++- kernel/sched/sched.h | 4 ++-- kernel/sched/stop_task.c | 3 ++- 7 files changed, 20 insertions(+), 9 deletions(-) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index ab50100..4f7a4e9 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -2001,7 +2001,10 @@ void enqueue_task(struct rq *rq, struct task_struct = *p, int flags) sched_core_enqueue(rq, p); } =20 -void dequeue_task(struct rq *rq, struct task_struct *p, int flags) +/* + * Must only return false when DEQUEUE_SLEEP. + */ +inline bool dequeue_task(struct rq *rq, struct task_struct *p, int flags) { if (sched_core_enabled(rq)) sched_core_dequeue(rq, p, flags); @@ -2015,7 +2018,7 @@ void dequeue_task(struct rq *rq, struct task_struct *= p, int flags) } =20 uclamp_rq_dec(rq, p); - p->sched_class->dequeue_task(rq, p, flags); + return p->sched_class->dequeue_task(rq, p, flags); } =20 void activate_task(struct rq *rq, struct task_struct *p, int flags) diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c index c5f1cc7..bbaeace 100644 --- a/kernel/sched/deadline.c +++ b/kernel/sched/deadline.c @@ -2162,7 +2162,7 @@ static void enqueue_task_dl(struct rq *rq, struct tas= k_struct *p, int flags) enqueue_pushable_dl_task(rq, p); } =20 -static void dequeue_task_dl(struct rq *rq, struct task_struct *p, int flag= s) +static bool dequeue_task_dl(struct rq *rq, struct task_struct *p, int flag= s) { update_curr_dl(rq); =20 @@ -2172,6 +2172,8 @@ static void dequeue_task_dl(struct rq *rq, struct tas= k_struct *p, int flags) dequeue_dl_entity(&p->dl, flags); if (!p->dl.dl_throttled && !dl_server(&p->dl)) dequeue_pushable_dl_task(rq, p); + + return true; } =20 /* diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 1452c53..03f76b3 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -6865,7 +6865,7 @@ static void set_next_buddy(struct sched_entity *se); * decreased. We remove the task from the rbtree and * update the fair scheduling stats: */ -static void dequeue_task_fair(struct rq *rq, struct task_struct *p, int fl= ags) +static bool dequeue_task_fair(struct rq *rq, struct task_struct *p, int fl= ags) { struct cfs_rq *cfs_rq; struct sched_entity *se =3D &p->se; @@ -6937,6 +6937,8 @@ static void dequeue_task_fair(struct rq *rq, struct t= ask_struct *p, int flags) dequeue_throttle: util_est_update(&rq->cfs, p, task_sleep); hrtick_update(rq); + + return true; } =20 #ifdef CONFIG_SMP diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c index d560f7f..1607420 100644 --- a/kernel/sched/idle.c +++ b/kernel/sched/idle.c @@ -482,13 +482,14 @@ struct task_struct *pick_next_task_idle(struct rq *rq) * It is not legal to sleep in the idle task - print a warning * message if some code attempts to do it: */ -static void +static bool dequeue_task_idle(struct rq *rq, struct task_struct *p, int flags) { raw_spin_rq_unlock_irq(rq); printk(KERN_ERR "bad: scheduling from the idle thread!\n"); dump_stack(); raw_spin_rq_lock_irq(rq); + return true; } =20 /* diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c index a8731da..fdc8e05 100644 --- a/kernel/sched/rt.c +++ b/kernel/sched/rt.c @@ -1483,7 +1483,7 @@ enqueue_task_rt(struct rq *rq, struct task_struct *p,= int flags) enqueue_pushable_task(rq, p); } =20 -static void dequeue_task_rt(struct rq *rq, struct task_struct *p, int flag= s) +static bool dequeue_task_rt(struct rq *rq, struct task_struct *p, int flag= s) { struct sched_rt_entity *rt_se =3D &p->rt; =20 @@ -1491,6 +1491,8 @@ static void dequeue_task_rt(struct rq *rq, struct tas= k_struct *p, int flags) dequeue_rt_entity(rt_se, flags); =20 dequeue_pushable_task(rq, p); + + return true; } =20 /* diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index a6d6b6f..6196f90 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -2285,7 +2285,7 @@ struct sched_class { #endif =20 void (*enqueue_task) (struct rq *rq, struct task_struct *p, int flags); - void (*dequeue_task) (struct rq *rq, struct task_struct *p, int flags); + bool (*dequeue_task) (struct rq *rq, struct task_struct *p, int flags); void (*yield_task) (struct rq *rq); bool (*yield_to_task)(struct rq *rq, struct task_struct *p); =20 @@ -3606,7 +3606,7 @@ extern int __sched_setaffinity(struct task_struct *p,= struct affinity_context *c extern void __setscheduler_prio(struct task_struct *p, int prio); extern void set_load_weight(struct task_struct *p, bool update_load); extern void enqueue_task(struct rq *rq, struct task_struct *p, int flags); -extern void dequeue_task(struct rq *rq, struct task_struct *p, int flags); +extern bool dequeue_task(struct rq *rq, struct task_struct *p, int flags); =20 extern void check_class_changed(struct rq *rq, struct task_struct *p, const struct sched_class *prev_class, diff --git a/kernel/sched/stop_task.c b/kernel/sched/stop_task.c index b1b8fe6..4cf0207 100644 --- a/kernel/sched/stop_task.c +++ b/kernel/sched/stop_task.c @@ -57,10 +57,11 @@ enqueue_task_stop(struct rq *rq, struct task_struct *p,= int flags) add_nr_running(rq, 1); } =20 -static void +static bool dequeue_task_stop(struct rq *rq, struct task_struct *p, int flags) { sub_nr_running(rq, 1); + return true; } =20 static void yield_task_stop(struct rq *rq)