From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) (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 23B983314AC; Wed, 10 Sep 2025 16:00:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=90.155.50.34 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757520044; cv=none; b=dNkuc3GTWYpBBJrzkNP7FnPNRxZHz0A2XaL5otcuCAJ+tPTpj/LPllWC0vRFeusGM6hX+a0sHuVBMSbvwpqQVPGNdgF8juKm/fZ+L8Tbb+/uOGoi5WiWIX4A5Gvzn3NDkfo4wVfwfaQig0VgBPkoajlhUAye3Y7wVm+0MiMyQ/8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757520044; c=relaxed/simple; bh=eJ4oXeYmnXgBRnf1RFj21yJ6/BQU/W/19x07jWAIl7U=; h=Message-ID:Date:From:To:Cc:Subject:References:MIME-Version: Content-Type; b=aNWgX8FYUyTLbWwT2gYsGI9TL7vSo9JBfE4ee0DXOm7YHXewR/7Ut3FxmQey5EE1IcnbU7yfY7KgB8yyWNvxQAizlpoBqnG3tMjRALSsTq3Smrt9jd5hNqOMsj9wdBwpMZzmwJfD89ermJX9z+o1okzZ770pIOTG8ZAo+Di4TrY= 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=WY4k2TO6; arc=none smtp.client-ip=90.155.50.34 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="WY4k2TO6" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; 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=SF/7cq/p/mZxCjyO1Uj0cUAjeatFeno/8Y4qP/ER83Q=; b=WY4k2TO6T3ojOF/rtHICSfVI6G tqwyqOPFGh/LXvur8NPxacLNpZcM2zrwa7ri3F3IdWhdgMv7zY7mJjy72Zg1KQRWYWuAbgmM64e8+ a3+vsUHqVmY/qTRsm9a0JOGWXqltd++j2cYWSShxrz9kMOMtwApAIbLuD1B9SoD6GOTnvAhCIsPA1 jOfoX8CBpRThoA4r/bS9lHo+wCoJbqpMMUq8bkUJxQLJJDr3o3nAi5k34CHLa2t/0Tj6cv4Mle/cj L5tLyKZdiHIbo0VRptMwzJ+SVblCCYuv/eGiJihThsl0SmOXkZxI7TXxPUV2EeI49wc9fgT/duSUu ZjhwLDZQ==; Received: from 77-249-17-252.cable.dynamic.v4.ziggo.nl ([77.249.17.252] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.98.2 #2 (Red Hat Linux)) id 1uwNFG-0000000BXpC-2zyL; Wed, 10 Sep 2025 16:00:30 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 0) id 8D9C6302EA6; Wed, 10 Sep 2025 18:00:28 +0200 (CEST) Message-ID: <20250910155808.876041318@infradead.org> User-Agent: quilt/0.68 Date: Wed, 10 Sep 2025 17:44:14 +0200 From: Peter Zijlstra To: tj@kernel.org Cc: linux-kernel@vger.kernel.org, peterz@infradead.org, mingo@redhat.com, juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, vschneid@redhat.com, longman@redhat.com, hannes@cmpxchg.org, mkoutny@suse.com, void@manifault.com, arighi@nvidia.com, changwoo@igalia.com, cgroups@vger.kernel.org, sched-ext@lists.linux.dev, liuwenfang@honor.com, tglx@linutronix.de Subject: [PATCH 05/14] sched: Move sched_class::prio_changed() into the change pattern References: <20250910154409.446470175@infradead.org> Precedence: bulk X-Mailing-List: cgroups@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Move sched_class::prio_changed() into the change pattern. And while there, extend it with sched_class::get_prio() in order to fix the deadline sitation. Suggested-by: Tejun Heo Signed-off-by: Peter Zijlstra (Intel) --- kernel/sched/core.c | 24 +++++++++++++----------- kernel/sched/deadline.c | 20 +++++++++++--------- kernel/sched/ext.c | 8 +------- kernel/sched/fair.c | 8 ++++++-- kernel/sched/idle.c | 5 ++++- kernel/sched/rt.c | 5 ++++- kernel/sched/sched.h | 7 ++++--- kernel/sched/stop_task.c | 5 ++++- kernel/sched/syscalls.c | 9 --------- 9 files changed, 47 insertions(+), 44 deletions(-) --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -2167,12 +2167,6 @@ inline int task_curr(const struct task_s return cpu_curr(task_cpu(p)) == p; } -void check_prio_changed(struct rq *rq, struct task_struct *p, int oldprio) -{ - if (oldprio != p->prio || dl_task(p)) - p->sched_class->prio_changed(rq, p, oldprio); -} - void wakeup_preempt(struct rq *rq, struct task_struct *p, int flags) { struct task_struct *donor = rq->donor; @@ -7437,9 +7431,6 @@ void rt_mutex_setprio(struct task_struct p->sched_class = next_class; p->prio = prio; } - - if (!(queue_flag & DEQUEUE_CLASS)) - check_prio_changed(rq, p, oldprio); out_unlock: /* Avoid rq from going away on us: */ preempt_disable(); @@ -10894,6 +10885,13 @@ struct sched_change_ctx *sched_change_be .running = task_current(rq, p), }; + if (!(flags & DEQUEUE_CLASS)) { + if (p->sched_class->get_prio) + ctx->prio = p->sched_class->get_prio(rq, p); + else + ctx->prio = p->prio; + } + if (ctx->queued) dequeue_task(rq, p, flags); if (ctx->running) @@ -10920,6 +10918,10 @@ void sched_change_end(struct sched_chang if (ctx->running) set_next_task(rq, p); - if ((ctx->flags & ENQUEUE_CLASS) && p->sched_class->switched_to) - p->sched_class->switched_to(rq, p); + if (ctx->flags & ENQUEUE_CLASS) { + if (p->sched_class->switched_to) + p->sched_class->switched_to(rq, p); + } else { + p->sched_class->prio_changed(rq, p, ctx->prio); + } } --- a/kernel/sched/deadline.c +++ b/kernel/sched/deadline.c @@ -3071,23 +3071,24 @@ static void switched_to_dl(struct rq *rq } } +static u64 get_prio_dl(struct rq *rq, struct task_struct *p) +{ + return p->dl.deadline; +} + /* * If the scheduling parameters of a -deadline task changed, * a push or pull operation might be needed. */ -static void prio_changed_dl(struct rq *rq, struct task_struct *p, - int oldprio) +static void prio_changed_dl(struct rq *rq, struct task_struct *p, u64 old_deadline) { if (!task_on_rq_queued(p)) return; - /* - * This might be too much, but unfortunately - * we don't have the old deadline value, and - * we can't argue if the task is increasing - * or lowering its prio, so... - */ - if (!rq->dl.overloaded) + if (p->dl.deadline == old_deadline) + return; + + if (dl_time_before(old_deadline, p->dl.deadline)) deadline_queue_pull_task(rq); if (task_current_donor(rq, p)) { @@ -3142,6 +3143,7 @@ DEFINE_SCHED_CLASS(dl) = { .task_tick = task_tick_dl, .task_fork = task_fork_dl, + .get_prio = get_prio_dl, .prio_changed = prio_changed_dl, .switched_from = switched_from_dl, .switched_to = switched_to_dl, --- a/kernel/sched/ext.c +++ b/kernel/sched/ext.c @@ -4023,7 +4023,7 @@ static void reweight_task_scx(struct rq p, p->scx.weight); } -static void prio_changed_scx(struct rq *rq, struct task_struct *p, int oldprio) +static void prio_changed_scx(struct rq *rq, struct task_struct *p, u64 oldprio) { } @@ -5015,9 +5015,6 @@ static void scx_disable_workfn(struct kt p->sched_class = new_class; } - if (!(queue_flags & DEQUEUE_CLASS)) - check_prio_changed(task_rq(p), p, p->prio); - scx_exit_task(p); } scx_task_iter_stop(&sti); @@ -5766,9 +5763,6 @@ static int scx_enable(struct sched_ext_o p->sched_class = new_class; } - if (!(queue_flags & DEQUEUE_CLASS)) - check_prio_changed(task_rq(p), p, p->prio); - put_task_struct(p); } scx_task_iter_stop(&sti); --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -13122,11 +13122,14 @@ static void task_fork_fair(struct task_s * the current task. */ static void -prio_changed_fair(struct rq *rq, struct task_struct *p, int oldprio) +prio_changed_fair(struct rq *rq, struct task_struct *p, u64 oldprio) { if (!task_on_rq_queued(p)) return; + if (p->prio == oldprio) + return; + if (rq->cfs.nr_queued == 1) return; @@ -13138,8 +13141,9 @@ prio_changed_fair(struct rq *rq, struct if (task_current_donor(rq, p)) { if (p->prio > oldprio) resched_curr(rq); - } else + } else { wakeup_preempt(rq, p, 0); + } } #ifdef CONFIG_FAIR_GROUP_SCHED --- a/kernel/sched/idle.c +++ b/kernel/sched/idle.c @@ -504,8 +504,11 @@ static void switching_to_idle(struct rq } static void -prio_changed_idle(struct rq *rq, struct task_struct *p, int oldprio) +prio_changed_idle(struct rq *rq, struct task_struct *p, u64 oldprio) { + if (p->prio == oldprio) + return; + BUG(); } --- a/kernel/sched/rt.c +++ b/kernel/sched/rt.c @@ -2437,11 +2437,14 @@ static void switched_to_rt(struct rq *rq * us to initiate a push or pull. */ static void -prio_changed_rt(struct rq *rq, struct task_struct *p, int oldprio) +prio_changed_rt(struct rq *rq, struct task_struct *p, u64 oldprio) { if (!task_on_rq_queued(p)) return; + if (p->prio == oldprio) + return; + if (task_current_donor(rq, p)) { /* * If our priority decreases while running, we --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -2426,8 +2426,10 @@ struct sched_class { void (*reweight_task)(struct rq *this_rq, struct task_struct *task, const struct load_weight *lw); + + u64 (*get_prio) (struct rq *this_rq, struct task_struct *task); void (*prio_changed) (struct rq *this_rq, struct task_struct *task, - int oldprio); + u64 oldprio); unsigned int (*get_rr_interval)(struct rq *rq, struct task_struct *task); @@ -3852,12 +3854,11 @@ extern void set_load_weight(struct task_ extern void enqueue_task(struct rq *rq, struct task_struct *p, int flags); extern bool dequeue_task(struct rq *rq, struct task_struct *p, int flags); -extern void check_prio_changed(struct rq *rq, struct task_struct *p, int oldprio); - extern struct balance_callback *splice_balance_callbacks(struct rq *rq); extern void balance_callbacks(struct rq *rq, struct balance_callback *head); struct sched_change_ctx { + u64 prio; struct task_struct *p; int flags; bool queued; --- a/kernel/sched/stop_task.c +++ b/kernel/sched/stop_task.c @@ -81,8 +81,11 @@ static void switching_to_stop(struct rq } static void -prio_changed_stop(struct rq *rq, struct task_struct *p, int oldprio) +prio_changed_stop(struct rq *rq, struct task_struct *p, u64 oldprio) { + if (p->prio == oldprio) + return; + BUG(); /* how!?, what priority? */ } --- a/kernel/sched/syscalls.c +++ b/kernel/sched/syscalls.c @@ -95,12 +95,6 @@ void set_user_nice(struct task_struct *p old_prio = p->prio; p->prio = effective_prio(p); } - - /* - * If the task increased its priority or is running and - * lowered its priority, then reschedule its CPU: - */ - p->sched_class->prio_changed(rq, p, old_prio); } EXPORT_SYMBOL(set_user_nice); @@ -708,9 +702,6 @@ int __sched_setscheduler(struct task_str } } - if (!(queue_flags & DEQUEUE_CLASS)) - check_prio_changed(rq, p, oldprio); - /* Avoid rq from going away on us: */ preempt_disable(); head = splice_balance_callbacks(rq);