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 AFE4534403A; Thu, 15 Jan 2026 09:06:18 +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=1768467984; cv=none; b=oHtohDP+8AAqtyBLQEkYzkaPV2Kyu4GB9yq/KSBIqxe7As4UXKQypbCiH54cHdLo9mvL0F/ddjy31kKkOgbrfP8evaJUOqTANFX+d75sgtXYsuAuHrPBSg97pIZnCOkxs85CaWuFk6k/6pqBz94QSudq06tUVGDz9Fy47JslRTM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768467984; c=relaxed/simple; bh=QtXrY1BzyAWQDCoRetiYhjCCl5TRbbzVkYeUJgUnpqs=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=tTPGOfY9qYe0GftGmCmqDZvPFnVyFYuOQUZOiIAcalsrYuUD8VaTDir0nLlOurQZU47QV9dOYUsTv3STpZvPxqvhxJN5BKN8qOL4kIDn/DCsx2Jufq+Yg6J838my+RYKaWHmD3QauStLNUWQZqOaGdwsRumP29FXHdRjSLAP680= 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=ov+K6aJn; 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="ov+K6aJn" 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=W598fxA4tcfvMZqVc/8UaYOmwTru2sIEcl6XEyPCud8=; b=ov+K6aJnY0lOzxO2t+3c6TMoVH vTnkg0gp81L5Oxdfmlws+DidoQ97YjbUmjLVXGX6510BRRwzLLGzfB7/95FpO1xUSikfzxRGDvWPf jnDoIoyIozzko7uVXBJqPIDj+S7joftX9xiMdPlq2CgVWF7t6H8gkYKuH8JiIDlZMxZCBfdCcOmYr r14Aofds/tK98SszhFaivACY5igabQGInvSZkTVThLe3ecriA1Osuo7WzWuBik/uF7msOUZL0xnrq V8ufw0iGBEt6pcPlpsgw2H6xklAQWxwUEQKHoH68dc+vQuu9/4vbVnjzvtb1+BMIo+gev+vxn2tal 7K78V3zQ==; 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 1vgJIl-00000006NX6-1gs6; Thu, 15 Jan 2026 09:06:02 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id E8D513005E5; Thu, 15 Jan 2026 10:05:57 +0100 (CET) Date: Thu, 15 Jan 2026 10:05:57 +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: <20260115090557.GC831285@noisy.programming.kicks-ass.net> References: <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> <20260115082431.GE830755@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: <20260115082431.GE830755@noisy.programming.kicks-ass.net> On Thu, Jan 15, 2026 at 09:24:31AM +0100, Peter Zijlstra wrote: > 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). Now live at: https://git.kernel.org/pub/scm/linux/kernel/git/peterz/queue.git/log/?h=sched/urgent Please test.