From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 17FD12D238F; Mon, 22 Jun 2026 14:46:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782139611; cv=none; b=qRx54y6oUz9Ygg+5GbowPx2P+U/rhWDBQMx/a7tXlS9aXL2kfrNze0PjOz3bOzBrgIya5oJhQeFOT4sxrC3Wu2/3pgd+6nB6yHbPxStR6DbebXKV+AJCfoXY85CfRrY0m6lyivVfJqvW+ireQuIObzaDiJG1d13czaZUMebGmpM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782139611; c=relaxed/simple; bh=CveggRhsgrjFSsakJwPsDvuDDQ5R/ETHLR1mdqNVN0w=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=NxvcATYo6mutYO7/no3uDVQxs+CukSWti/dGMkRuIdpNsAJKAD4f0ZpdhvGgOPx+sxqnv2vUAUULBaD/VsB18oI3oy6gSkP9Ha43+AC8hXPUX9ARp/1ByskiOpI/12l0uR9Pz6wdhQA2lBAjyjO76BJxvXWH2a/T4hZZ6QeyLkw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=f/dUu62/; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="f/dUu62/" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 010381F000E9; Mon, 22 Jun 2026 14:46:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1782139610; bh=dxwTwz2SjD/WcO6OIuYmtGdS2obIyzDQ1lRUGnpLI9U=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=f/dUu62/BAO/YvHFsOdZkJ5/zt9b1JENiN2EKg1U3LDK3eLWp40nCGN4UdeF3IJma 1xkilKAHt2SP3XW8dXtcS2kjgvVtQ3/Hv46rAR/TMC1jtnPA2Trcb70j9vlErX+V8J 0skzupHw+AO2XBnyAAHle5t0zpAA6jQHSVI83M/GK/dZoQeoxUn6DOj91JU17WPgM4 lMrRU709PY+C8WE2epqosWPs7t1LOHBUEo0aby4zWdEYjwdynldKgC5V6Bv52UZubn N9BvfgxVZMEIpq5Kw7HSZNxP5h88evGHRFOG/jYNSzZiyAaTabBK9k87pS2/XluC5L 6rslLdBIgIIyw== Message-ID: <79aa1649-acbb-4898-b533-4c991a6ca19b@kernel.org> Date: Mon, 22 Jun 2026 16:46:48 +0200 Precedence: bulk X-Mailing-List: virtualization@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 1/2] virtio_balloon: factor out virtballoon_quiesce() To: "Denis V. Lunev" , mst@redhat.com Cc: virtualization@lists.linux.dev, linux-kernel@vger.kernel.org References: <20260622133715.3707707-1-den@openvz.org> <20260622133715.3707707-2-den@openvz.org> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; keydata= xsFNBFXLn5EBEAC+zYvAFJxCBY9Tr1xZgcESmxVNI/0ffzE/ZQOiHJl6mGkmA1R7/uUpiCjJ dBrn+lhhOYjjNefFQou6478faXE6o2AhmebqT4KiQoUQFV4R7y1KMEKoSyy8hQaK1umALTdL QZLQMzNE74ap+GDK0wnacPQFpcG1AE9RMq3aeErY5tujekBS32jfC/7AnH7I0v1v1TbbK3Gp XNeiN4QroO+5qaSr0ID2sz5jtBLRb15RMre27E1ImpaIv2Jw8NJgW0k/D1RyKCwaTsgRdwuK Kx/Y91XuSBdz0uOyU/S8kM1+ag0wvsGlpBVxRR/xw/E8M7TEwuCZQArqqTCmkG6HGcXFT0V9 PXFNNgV5jXMQRwU0O/ztJIQqsE5LsUomE//bLwzj9IVsaQpKDqW6TAPjcdBDPLHvriq7kGjt WhVhdl0qEYB8lkBEU7V2Yb+SYhmhpDrti9Fq1EsmhiHSkxJcGREoMK/63r9WLZYI3+4W2rAc UucZa4OT27U5ZISjNg3Ev0rxU5UH2/pT4wJCfxwocmqaRr6UYmrtZmND89X0KigoFD/XSeVv jwBRNjPAubK9/k5NoRrYqztM9W6sJqrH8+UWZ1Idd/DdmogJh0gNC0+N42Za9yBRURfIdKSb B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABzS5EYXZpZCBIaWxk ZW5icmFuZCAoQ3VycmVudCkgPGRhdmlkQGtlcm5lbC5vcmc+wsGQBBMBCAA6AhsDBQkmWAik AgsJBBUKCQgCFgICHgUCF4AWIQQb2cqtc1xMOkYN/MpN3hD3AP+DWgUCaYJt/AIZAQAKCRBN 3hD3AP+DWriiD/9BLGEKG+N8L2AXhikJg6YmXom9ytRwPqDgpHpVg2xdhopoWdMRXjzOrIKD g4LSnFaKneQD0hZhoArEeamG5tyo32xoRsPwkbpIzL0OKSZ8G6mVbFGpjmyDLQCAxteXCLXz ZI0VbsuJKelYnKcXWOIndOrNRvE5eoOfTt2XfBnAapxMYY2IsV+qaUXlO63GgfIOg8RBaj7x 3NxkI3rV0SHhI4GU9K6jCvGghxeS1QX6L/XI9mfAYaIwGy5B68kF26piAVYv/QZDEVIpo3t7 /fjSpxKT8plJH6rhhR0epy8dWRHk3qT5tk2P85twasdloWtkMZ7FsCJRKWscm1BLpsDn6EQ4 jeMHECiY9kGKKi8dQpv3FRyo2QApZ49NNDbwcR0ZndK0XFo15iH708H5Qja/8TuXCwnPWAcJ DQoNIDFyaxe26Rx3ZwUkRALa3iPcVjE0//TrQ4KnFf+lMBSrS33xDDBfevW9+Dk6IISmDH1R HFq2jpkN+FX/PE8eVhV68B2DsAPZ5rUwyCKUXPTJ/irrCCmAAb5Jpv11S7hUSpqtM/6oVESC 3z/7CzrVtRODzLtNgV4r5EI+wAv/3PgJLlMwgJM90Fb3CB2IgbxhjvmB1WNdvXACVydx55V7 LPPKodSTF29rlnQAf9HLgCphuuSrrPn5VQDaYZl4N/7zc2wcWM7BTQRVy5+RARAA59fefSDR 9nMGCb9LbMX+TFAoIQo/wgP5XPyzLYakO+94GrgfZjfhdaxPXMsl2+o8jhp/hlIzG56taNdt VZtPp3ih1AgbR8rHgXw1xwOpuAd5lE1qNd54ndHuADO9a9A0vPimIes78Hi1/yy+ZEEvRkHk /kDa6F3AtTc1m4rbbOk2fiKzzsE9YXweFjQvl9p+AMw6qd/iC4lUk9g0+FQXNdRs+o4o6Qvy iOQJfGQ4UcBuOy1IrkJrd8qq5jet1fcM2j4QvsW8CLDWZS1L7kZ5gT5EycMKxUWb8LuRjxzZ 3QY1aQH2kkzn6acigU3HLtgFyV1gBNV44ehjgvJpRY2cC8VhanTx0dZ9mj1YKIky5N+C0f21 zvntBqcxV0+3p8MrxRRcgEtDZNav+xAoT3G0W4SahAaUTWXpsZoOecwtxi74CyneQNPTDjNg azHmvpdBVEfj7k3p4dmJp5i0U66Onmf6mMFpArvBRSMOKU9DlAzMi4IvhiNWjKVaIE2Se9BY FdKVAJaZq85P2y20ZBd08ILnKcj7XKZkLU5FkoA0udEBvQ0f9QLNyyy3DZMCQWcwRuj1m73D sq8DEFBdZ5eEkj1dCyx+t/ga6x2rHyc8Sl86oK1tvAkwBNsfKou3v+jP/l14a7DGBvrmlYjO 59o3t6inu6H7pt7OL6u6BQj7DoMAEQEAAcLBfAQYAQgAJgIbDBYhBBvZyq1zXEw6Rg38yk3e EPcA/4NaBQJonNqrBQkmWAihAAoJEE3eEPcA/4NaKtMQALAJ8PzprBEXbXcEXwDKQu+P/vts IfUb1UNMfMV76BicGa5NCZnJNQASDP/+bFg6O3gx5NbhHHPeaWz/VxlOmYHokHodOvtL0WCC 8A5PEP8tOk6029Z+J+xUcMrJClNVFpzVvOpb1lCbhjwAV465Hy+NUSbbUiRxdzNQtLtgZzOV Zw7jxUCs4UUZLQTCuBpFgb15bBxYZ/BL9MbzxPxvfUQIPbnzQMcqtpUs21CMK2PdfCh5c4gS sDci6D5/ZIBw94UQWmGpM/O1ilGXde2ZzzGYl64glmccD8e87OnEgKnH3FbnJnT4iJchtSvx yJNi1+t0+qDti4m88+/9IuPqCKb6Stl+s2dnLtJNrjXBGJtsQG/sRpqsJz5x1/2nPJSRMsx9 5YfqbdrJSOFXDzZ8/r82HgQEtUvlSXNaXCa95ez0UkOG7+bDm2b3s0XahBQeLVCH0mw3RAQg r7xDAYKIrAwfHHmMTnBQDPJwVqxJjVNr7yBic4yfzVWGCGNE4DnOW0vcIeoyhy9vnIa3w1uZ 3iyY2Nsd7JxfKu1PRhCGwXzRw5TlfEsoRI7V9A8isUCoqE2Dzh3FvYHVeX4Us+bRL/oqareJ CIFqgYMyvHj7Q06kTKmauOe4Nf0l0qEkIuIzfoLJ3qr5UyXc2hLtWyT9Ir+lYlX9efqh7mOY qIws/H2t In-Reply-To: <20260622133715.3707707-2-den@openvz.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 6/22/26 15:37, Denis V. Lunev wrote: > virtballoon_remove() stops all of the balloon's asynchronous work (the > free page reporting worker, the inflate/deflate and stats workers, the > OOM notifier and the free page shrinker) before tearing the device > down. A following change needs the same teardown from a .shutdown > handler, so move it into a virtballoon_quiesce() helper. > > No functional change. > > Signed-off-by: Denis V. Lunev > --- > drivers/virtio/virtio_balloon.c | 27 ++++++++++++++++++++------- > 1 file changed, 20 insertions(+), 7 deletions(-) > > diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c > index 088b3a0e6ce6..5b02d9191ac6 100644 > --- a/drivers/virtio/virtio_balloon.c > +++ b/drivers/virtio/virtio_balloon.c > @@ -1098,26 +1098,39 @@ static void remove_common(struct virtio_balloon *vb) > vb->vdev->config->del_vqs(vb->vdev); > } > > -static void virtballoon_remove(struct virtio_device *vdev) > +/* > + * Stop all asynchronous balloon work. The device must still be alive so that > + * in-flight requests can drain via the host before it is reset or freed. > + */ > +static void virtballoon_quiesce(struct virtio_balloon *vb) > { > - struct virtio_balloon *vb = vdev->priv; > + struct virtio_device *vdev = vb->vdev; > > - if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_REPORTING)) > + if (virtio_has_feature(vdev, VIRTIO_BALLOON_F_REPORTING)) > page_reporting_unregister(&vb->pr_dev_info); Most functions here grab mutexes and can sleep. I assume that's fine in shutdown context. Nothing jumped at me Sashiko asks whether ->remove (hotunplug/driver-unloading) can follow a ->shutdown callback. I don't know, seems questionable if this could happen and should probably be handled by the core? If it's possible you'd have to remember that stuff was already quiesce'ed. Maybe simply by checking early in virtballoon_quiesce() whether vb->stop_update == true already. -- Cheers, David