From mboxrd@z Thu Jan 1 00:00:00 1970 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.subspace.kernel.org (Postfix) with ESMTPS id AAFF42E401; Sun, 9 Aug 2026 23:15:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.137.202.133 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786317337; cv=none; b=PPCfFCtOJ6tZGQEbfiJ+e1v8VE4FWKObUKX9TkYp6VNTgMcpx0fdAdnY/fljpGMiNxuZ2G/HLo0NZsqi+dgqWYAxpiSVqnKXo+OFHY6AOJcKZrBBBZmeNV3lR083xi0gYdLvGR3cPGNQw6pjqVQiPvmMmc8vwIPMHUQV6WLvgtk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786317337; c=relaxed/simple; bh=HkgiL877x1NhAZjHcTrix8HGGel5Y3l+BrxwBDUSSPU=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=F/XUeoFnz66PAV1liy00qjWvM0H3wGk0+f9gENbXDqoKq5kyveZM9ZRYeuAj2Pvxd4nUCGngyG0CCPNtPs/RbAhT5biIoCKeSQRm8dvy49ThHY/wRPwOYqNOiKMdCTxGwJdGpar0Vs1rBjV+3DbNMnTa6BSee4sLzD2IZ1gG9Pk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org; spf=pass smtp.mailfrom=infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=oo+FFzlK; arc=none smtp.client-ip=198.137.202.133 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=pass 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="oo+FFzlK" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=Content-Transfer-Encoding: Content-Type:In-Reply-To:From:References:Cc:To:Subject:MIME-Version:Date: Message-ID:Sender:Reply-To:Content-ID:Content-Description; bh=SoBiIcUKkLsP6UDETpX1PzwZE2TvLHRfs52WUirHK+E=; b=oo+FFzlKcz078c83/WyrtUw+PW iA1GgatjSrSZ2aKBBZC/4vkfPF9T1Y1YCL1Yr1HT9o1ckIjoA2fHIzbQnIyNNHZFN4JMDq3rLPLMe 7BRSTJfDx8CxljivNobV952ucQx5CxpBXMD4RV8UBLifcaqTkyytP46D3OeKMHd3EL9OfTUNFAXD2 bRqfB5c4Jq8Gp97Us1mvgXuwJFQML2kXk/v5Z3ApgazaGTdm3yUo4ZcRRO+e2jKKueche8CA1W2fU VKSDlERWqeFW8c8MWJDknrnSXTDqlfMrLsDTbta6D73qrB9EpFtO4NuL+SLT+fgjsVPbOidC10FQj Mpn919Tw==; Received: from [50.53.43.113] (helo=[192.168.254.34]) by bombadil.infradead.org with esmtpsa (Exim 4.99.1 #2 (Red Hat Linux)) id 1wtCjn-0000000Ap9n-1LGv; Sun, 09 Aug 2026 23:15:28 +0000 Message-ID: <3f225be6-c87d-433d-9589-231d37ca6360@infradead.org> Date: Sun, 9 Aug 2026 16:15:25 -0700 Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [RFC PATCH 12/12] virtio: guarantee a virtqueue can publish its first descriptor chain To: "Michael S. Tsirkin" , Alexander Graf Cc: Jason Wang , Xuan Zhuo , =?UTF-8?Q?Eugenio_P=C3=A9rez?= , Jonathan Corbet , Shuah Khan , virtualization@lists.linux.dev, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, nh-open-source@amazon.com, Stefan Hajnoczi , Paolo Bonzini References: <20260809182010.32931-1-graf@amazon.com> <20260809182010.32931-13-graf@amazon.com> <20260809184014-mutt-send-email-mst@kernel.org> Content-Language: en-US From: Randy Dunlap In-Reply-To: <20260809184014-mutt-send-email-mst@kernel.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 8/9/26 3:41 PM, Michael S. Tsirkin wrote: > On Sun, Aug 09, 2026 at 06:20:10PM +0000, Alexander Graf wrote: >> A device's pool is shared by every virtqueue it has and nothing >> partitions it between them, so a virtqueue that asks late can get >> nothing at all. virtnet_open() pre-fills the receive queues in index >> order and discards the result, and a queue that came up with nothing is >> one the device cannot signal a completion on. >> >> Withhold a range of the pool from ordinary claims and let a virtqueue >> whose ring is empty draw on it for one descriptor chain. > Why bother? one chain can just go inline in the ring. https://people.kernel.org/tglx/notes-about-netiquette or https://subspace.kernel.org/etiquette.html It would be good if 100s (or 1000s) or people didn't need to scan a 65 KB email to see that most of it can be ignored. -- ~Randy