From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 9CFE1D13C13 for ; Mon, 26 Jan 2026 13:52:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=Ky62GUwPERN/e0pyAb7yB0pYqm86UmimVZKdDJ3jtbo=; b=i/GZbmwC02S85qwva39nzj2sxy 72lZYEq6QFy5BsY61b8beDPF9gz3/BmsMyk1PIkGWU2RKPigUseaFvTfZV7pH5AEj6aES2aKK/QT5 knBZujjVnTdyJOGyTLMYKMxBAIHSvbQeVbDO9FLi2TqNAvKuDUMU/Aie3By5CS/XVEMo1T/PJ8D21 k1sfDAhy/9kFjTTfLXywYRWZGTN7Qj2NhiMTcwKRGEnTY5SGDEKRyLnL8QG8pwwtIzDOf5AWy5zh/ 25lSFLHvZifxIHtlf6FIvjaRXNsK+N6gL2D2YD7N0XhH4ofHAlakreNw+O52C0TH0zIR4YizammYe mGm8Qk9Q==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vkN0r-0000000Ce3s-3wZc; Mon, 26 Jan 2026 13:52:17 +0000 Received: from tor.source.kernel.org ([172.105.4.254]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1vkN0q-0000000Ce3k-3BLC for linux-arm-kernel@lists.infradead.org; Mon, 26 Jan 2026 13:52:16 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by tor.source.kernel.org (Postfix) with ESMTP id ADA94600C3; Mon, 26 Jan 2026 13:52:15 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D689CC116C6; Mon, 26 Jan 2026 13:52:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1769435535; bh=kcA2cPiJEC19HBEstbYBifZWvAw98I0XK00+8H10mco=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=kVVmZvFr+CRLz0dBd5XLWyUavbW8nCgjkNtfsZ68viSoUlQzfs77mgqO6yT/jpeN8 pg7kQkZ+GT9I3gBbH5KSW1N19v6LZBDwYGLOWXiqcQylBZ5g4+KO6kKGQcqEiAcp10 ausowbCOUHsZ9bfKrKj7R3xBLNET1yxkp9J+5MLTEWX7f4No1SfT5XTL6aSPrTfT+N bCZy9asASdQMt42TI+gLu+rK/RLraHfA4D5BqFAPeAolk0a/hyw0wdylU0k19HWyrL x4wXKWwVwt8GOfxwvDBurrXf2OyecnDAn/Q+0+zLdQYHvjvwQgg6PufPEP9PU1/i/q WOFYplVNvnCcg== Date: Mon, 26 Jan 2026 13:52:05 +0000 From: Will Deacon To: Frederic Weisbecker Cc: LKML , Michal =?iso-8859-1?Q?Koutn=FD?= , Andrew Morton , Bjorn Helgaas , Catalin Marinas , Chen Ridong , Danilo Krummrich , "David S . Miller" , Eric Dumazet , Gabriele Monaco , Greg Kroah-Hartman , Ingo Molnar , Jakub Kicinski , Jens Axboe , Johannes Weiner , Lai Jiangshan , Marco Crivellari , Michal Hocko , Muchun Song , Paolo Abeni , Peter Zijlstra , Phil Auld , "Rafael J . Wysocki" , Roman Gushchin , Shakeel Butt , Simon Horman , Tejun Heo , Thomas Gleixner , Vlastimil Babka , Waiman Long , cgroups@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-block@vger.kernel.org, linux-mm@kvack.org, linux-pci@vger.kernel.org, netdev@vger.kernel.org Subject: Re: [PATCH 29/33] sched/arm64: Move fallback task cpumask to HK_TYPE_DOMAIN Message-ID: References: <20260125224541.50226-1-frederic@kernel.org> <20260125224541.50226-30-frederic@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260125224541.50226-30-frederic@kernel.org> X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Sun, Jan 25, 2026 at 11:45:36PM +0100, Frederic Weisbecker wrote: > When none of the allowed CPUs of a task are online, it gets migrated > to the fallback cpumask which is all the non nohz_full CPUs. > > However just like nohz_full CPUs, domain isolated CPUs don't want to be > disturbed by tasks that have lost their CPU affinities. > > And since nohz_full rely on domain isolation to work correctly, the > housekeeping mask of domain isolated CPUs should always be a subset of > the housekeeping mask of nohz_full CPUs (there can be CPUs that are > domain isolated but not nohz_full, OTOH there shouldn't be nohz_full > CPUs that are not domain isolated): > > HK_TYPE_DOMAIN & HK_TYPE_KERNEL_NOISE == HK_TYPE_DOMAIN > > Therefore use HK_TYPE_DOMAIN as the appropriate fallback target for > tasks. Note that cpuset isolated partitions are not supported on those > systems and may result in undefined behaviour. > > Signed-off-by: Frederic Weisbecker > Reviewed-by: Waiman Long > --- > Documentation/arch/arm64/asymmetric-32bit.rst | 12 ++++++++---- > arch/arm64/kernel/cpufeature.c | 6 +++--- > 2 files changed, 11 insertions(+), 7 deletions(-) Thanks, Frederic, this looks much better to me. I also chucked my old tests at it and it looked good, so: Acked-by: Will Deacon Tested-by: Will Deacon Will