From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 AF494245012; Mon, 26 Jan 2026 13:52:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769435535; cv=none; b=BrfM0dmAti2cZ1bT4uVYA41NG0Xg9jG6BpeuzBD2Q2YTgjioq9OO2k87ovuciQpVXxReL0TlIUxN5qPpCGMCHYVqBLAxgnsPQV1yhA8rpsOsaYl7KMeeDAMZI0+gqwgTTtxhQccHczUckcMIpTPPpLBfHy3DfAvjM5HL2TQjQqA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769435535; c=relaxed/simple; bh=kcA2cPiJEC19HBEstbYBifZWvAw98I0XK00+8H10mco=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=COy4BX2RBRqXVkb24tlUo0n3vroEDHvCudZtWO78gOb0D85lnYqkY3ZygHyc1xIMzo7ud47dAUDOKRLtr85aNuMxEv53JsRIsDwRsjNse4eM7lLzyE5BGR750OXgq8mw2EHrAoANxugkzz/gc+5JO9HCJFh7gTlK5Uf92+eJ9IM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=kVVmZvFr; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="kVVmZvFr" 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> 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: <20260125224541.50226-30-frederic@kernel.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