From mboxrd@z Thu Jan 1 00:00:00 1970 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 F2266329391; Thu, 15 Jan 2026 08:24:45 +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=1768465489; cv=none; b=P6nX7DECY9fGs5/Qb43ZE6Ie39nIz/NqHP657v9/Ua+fEsIdYRfYu4mlTWdU4Afx0ecvHA2lp179oqPnPp4oBCJV6dNcEXvmAf5jw1HjHeu2luIr11bcbW2yP52cJhc/ANQHdjraAfSkAi+lN+w8U+GlxFujBjE/8EpapviSCm0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768465489; c=relaxed/simple; bh=GEaJaYja87liXR/q22FlYoPhaUg3S5zvknrgF1mAW8Q=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=gPpBhJnEehJvAi9vIRLntFA+IDU2ryd963vPmX5RG8AUvsUxvRxDriAWW5hWSRCt+kd5AdNUNqN/O5lnyqFc9BWYxvGZ05yjqbeHBw/XNFzCBwRhGu1LDRAGpZMJZ0lh4iThsLWRfrXyV06k4qBgYU4T/euT95sFrVhxEjQnfBE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (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=IFUp94qq; arc=none smtp.client-ip=90.155.92.199 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (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="IFUp94qq" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=e8bAwWOZUjeh0Al8L+kGdtyWhBXYH7ec6q2qya2+mgM=; b=IFUp94qqSjhIRMhAwhzWLblRyM 8mLv1AoTNZQBe30imwXjgVnSC26vrj68N/qQU/VqfVimaVgoDTAx2xFJkCvzZrZZRbaSM/oxRYv4V ppFKA/nGg30+k4VoBFCJoEpaftVvv8t3TbU5G08zlLMoFWcOoWFTE0VqhbATRkm8AS+32cqZv1rps oOVJ3qbm7nXC8Ei8xwT9EPIxJu15gJyXBXvYxD4cBqY4QkTP+f1F/ARaWPLakIAtNy8IRXOkBr+Ki nTM4opEQpJriyUsO9zO7Y/50Xb1ZJPqRAZbxWUwuJgkhkLfR2NbACweBziuJDOppvlDZy7pYSYbU1 gkFJHZ/g==; Received: from 2001-1c00-8d85-5700-266e-96ff-fe07-7dcc.cable.dynamic.v6.ziggo.nl ([2001:1c00:8d85:5700:266e:96ff:fe07:7dcc] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.98.2 #2 (Red Hat Linux)) id 1vgIee-00000006J0Q-0WWn; Thu, 15 Jan 2026 08:24:32 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id 758CF30049A; Thu, 15 Jan 2026 09:24:31 +0100 (CET) Date: Thu, 15 Jan 2026 09:24:31 +0100 From: Peter Zijlstra To: Juri Lelli Cc: K Prateek Nayak , Pierre Gondois , tj@kernel.org, linux-kernel@vger.kernel.org, mingo@kernel.org, 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, Christian Loehle , luca.abeni@santannapisa.it Subject: Re: [PATCH 05/12] sched: Move sched_class::prio_changed() into the change pattern Message-ID: <20260115082431.GE830755@noisy.programming.kicks-ass.net> References: <20251006104402.946760805@infradead.org> <20251006104527.083607521@infradead.org> <717a0743-6d8f-4e35-8f2f-70a158b31147@arm.com> <20260113114718.GA831050@noisy.programming.kicks-ass.net> <20260114102336.GZ830755@noisy.programming.kicks-ass.net> <20260114130528.GB831285@noisy.programming.kicks-ass.net> Precedence: bulk X-Mailing-List: cgroups@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Wed, Jan 14, 2026 at 03:20:48PM +0100, Juri Lelli wrote: > > --- a/kernel/sched/syscalls.c > > +++ b/kernel/sched/syscalls.c > > @@ -639,7 +639,7 @@ int __sched_setscheduler(struct task_str > > * itself. > > */ > > newprio = rt_effective_prio(p, newprio); > > - if (newprio == oldprio) > > + if (newprio == oldprio && !dl_prio(newprio)) > > queue_flags &= ~DEQUEUE_MOVE; > > } > > We have been using (improperly?) ENQUEUE_SAVE also to know when a new > entity gets setscheduled to DEADLINE (or its parameters are changed) and > it looks like this keeps that happening with DEQUEUE_MOVE. So, from a > quick first look, it does sound good to me. If this is strictly about tasks coming into SCHED_DEADLINE there are a number of alternative options: - there are the sched_class::switch{ing,ed}_to() callbacks; - there is (the fairly recent) ENQUEUE_CLASS. Anyway, let me break up this one patch into individual bits and write changelogs. I'll stick them in queue/sched/urgent for now; hopefully Pierre can given them a spin and report back if it all sorts his problem).