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 50CC919F11B; Tue, 28 Jan 2025 14:39:59 +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=1738075201; cv=none; b=d8bNSw3EUSmyFt10fcItnO+CDrpzbDRvNXaPXVAu8disQwi4D3TPhavpUoQMAXbLgVTPvZSjrg+WtoWb2BL9pfE5bhf6VHeEU2yv0G0sGH1T+fyOOAfyFjc+uYh8o1PUtuCek+Ubv5rLdpL2AkG7CVv5isiS3R463Wu1HhaqA60= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738075201; c=relaxed/simple; bh=oUcTmcVAmNBZ/NoDI3YkTtH9irf1hslfk+eA3qNUay0=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=I9yf1qL12hyrBli0N2zSMa0J6UUK/xwyFuQv53wWyeknO9EWzSPDxBIQs2m7AJ/8tDkZhlHO/iweUvq0tBb8Kq4urxV84PwUV6c6ePyDaDxPpFdTepyBbArLAiNrSroCfXgrSTE/LNTTccSZze0dL1qmj/hpfhL/egOUfDtbeAc= 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=koBlIwM7; 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="koBlIwM7" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; 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=huiVco/j3yKRvxHPwa1DDY+QxVnKZ9Xl4BeWWMs3dZA=; b=koBlIwM7RLZP1G4gVu/71LraDv 8b1TJvLc79rwb99oP3p4SN71ErJbQ+t39XoJCMRmobl4YNv6syeeOiIM+3cJ1IZyg7VF1VVpzCd85 v6xG6gQdpMpp5pW5/HriTotehxMQ9/8wVr7CaL9cO8kSf65pNoWKUNvW+6+Qm+ZUmmgeUQIQzqf6r JJXY7p9MMc13A3TG/DWrsqaDGVZhaocelraT07yZnDea5XBVIgKrN2/fkL5c7PwOMrZbphoOiZX0z I/0pYmTkdKV4L/ooBuEUp8WA19FLhWDJ9z0W9DKBP7u0q/+qBtLypXjy2f16fmrg3jc5Ce+i4TUGb 2nvfcIDg==; Received: from 77-249-17-89.cable.dynamic.v4.ziggo.nl ([77.249.17.89] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.98 #2 (Red Hat Linux)) id 1tcmko-0000000AihY-25Lf; Tue, 28 Jan 2025 14:39:50 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id 8C6FA30050D; Tue, 28 Jan 2025 15:39:49 +0100 (CET) Date: Tue, 28 Jan 2025 15:39:49 +0100 From: Peter Zijlstra To: Mike Galbraith Cc: Ron Economos , Arnd Bergmann , Naresh Kamboju , Greg Kroah-Hartman , stable@vger.kernel.org, patches@lists.linux.dev, linux-kernel@vger.kernel.org, Linus Torvalds , Andrew Morton , Guenter Roeck , shuah , patches@kernelci.org, lkft-triage@lists.linaro.org, Pavel Machek , Jon Hunter , Florian Fainelli , Sudip Mukherjee , srw@sladewatkins.net, rwarsow@gmx.de, Conor Dooley , hargar@microsoft.com, Mark Brown , Anders Roxell , Vincent Guittot , Dan Carpenter Subject: Re: [PATCH 6.12 000/122] 6.12.11-rc1 review Message-ID: <20250128143949.GD7145@noisy.programming.kicks-ass.net> References: <20250121174532.991109301@linuxfoundation.org> <20250122105949.GK7145@noisy.programming.kicks-ass.net> Precedence: bulk X-Mailing-List: stable@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 Tue, Jan 28, 2025 at 12:46:07PM +0100, Mike Galbraith wrote: > Seems 6.13 is gripe free thanks to it containing 4423af84b297. > > I stumbled upon a reproducer for my x86_64 desktop box: all I need do > is fire up a kvm guest in an enterprise configured host. That inspires > libvirt goop to engage group scheduling, splat follows instantly. > > Back 4423af84b297 out of 6.13, it starts griping, add it to a 6.12 tree > containing 6d71a9c61604, it stops doing so. Ooh, does something like the below (+- reverse-renames as applicable to .12) also help? --- diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index b67222dea491..8766f7d3d297 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -3781,6 +3781,7 @@ static void reweight_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, update_entity_lag(cfs_rq, se); se->deadline -= se->vruntime; se->rel_deadline = 1; + cfs_rq->nr_queued--; if (!curr) __dequeue_entity(cfs_rq, se); update_load_sub(&cfs_rq->load, se->load.weight); @@ -3811,6 +3812,7 @@ static void reweight_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, place_entity(cfs_rq, se, 0); if (!curr) __enqueue_entity(cfs_rq, se); + cfs_rq->nr_queued++; /* * The entity's vruntime has been adjusted, so let's check