From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from vps0.lunn.ch (vps0.lunn.ch [156.67.10.101]) (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 A80AF3A8CE; Tue, 13 Aug 2024 14:07:00 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=156.67.10.101 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723558022; cv=none; b=jD3OqlQs2pU8Y5/TmPB6G88ukMiOiKnpraXCetaPeaPAI5EjvlugU3V9Wl7SiIo7NHIz4q7JoITvOZeuj9234xMoGlmL5QzO2J83nRCjcgOJSzZYFWt4GrLN7UsHjByvU+AQrYeuvHUKD+9STZk4NGO2X1qgyDMA9j/wGn9U4Lk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723558022; c=relaxed/simple; bh=eP+XEdCR1KUU2cjZqfxOFd9Vh9Bw+zlNK0kQu5w+Ne8=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=VMFccY5tskPW/D8E/rdpGhZcMjDb3JKx3sdgX/S1zRVFTRIzuIxczkLS4sgn2eqiXJVoiGZ8iAqJNWMIns0sYRU7ioHQ+ez0mXWI52XLLBVKrOOUYsr8yLlKjtRTbR2tg6sR2fKZZlJXpvEN8Z0bcwZcb5N59bD1Xa+RkKKx6sQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=lunn.ch; spf=pass smtp.mailfrom=lunn.ch; dkim=pass (1024-bit key) header.d=lunn.ch header.i=@lunn.ch header.b=1kHyrHpH; arc=none smtp.client-ip=156.67.10.101 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=lunn.ch Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=lunn.ch Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=lunn.ch header.i=@lunn.ch header.b="1kHyrHpH" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lunn.ch; s=20171124; h=In-Reply-To:Content-Disposition:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:From:Sender:Reply-To:Subject: Date:Message-ID:To:Cc:MIME-Version:Content-Type:Content-Transfer-Encoding: Content-ID:Content-Description:Content-Disposition:In-Reply-To:References; bh=XjvtdBWhIB3jnaC/VSJnnGrzxMjaNNlM2ipFgRhPhh0=; b=1kHyrHpH5Deq/apHEKzacsp6Qg hFzdHrgs6rP9M7inFWaTQyPt7mEaAkAO2eBcLE3ksAwOzAfagBPgS0jPVYFGLayWL9OManZlaapal E7z/lvbiNjrmPhCbpwbFYzrhnuQqgiHbniHoXTcnRhC8dt/XKxicwcCNYS5OT28ddTRU=; Received: from andrew by vps0.lunn.ch with local (Exim 4.94.2) (envelope-from ) id 1sdsAa-004gij-MM; Tue, 13 Aug 2024 16:06:40 +0200 Date: Tue, 13 Aug 2024 16:06:40 +0200 From: Andrew Lunn To: Paul Barker Cc: Sergey Shtylyov , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Niklas =?iso-8859-1?Q?S=F6derlund?= , Biju Das , Claudiu Beznea , Lad Prabhakar , Mitsuhiro Kimura , netdev@vger.kernel.org, linux-renesas-soc@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [net-next PATCH 2/2] net: ravb: Fix R-Car RX frame size limit Message-ID: References: <20240615103038.973-1-paul.barker.ct@bp.renesas.com> <20240615103038.973-3-paul.barker.ct@bp.renesas.com> <933ffa58-8092-4768-993d-cd62897d203d@bp.renesas.com> <524873e1-d770-4f29-a374-dab99fe87c14@bp.renesas.com> Precedence: bulk X-Mailing-List: linux-kernel@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: <524873e1-d770-4f29-a374-dab99fe87c14@bp.renesas.com> > Apologies, my response here is abysmally late due to illness, other > priorities and then the loss of my main dev box. Not a problem, life happens. > As you've said, a number of devices do not limit received packet size to > the MTU. There are many applications, other than a gateway, where using > jumbo packets in even just one direction would be beneficial. For > example if an application needs to receive large amounts of data but > only needs to send back control and acknowledgement messages. I think we > should support this where possible. This is the thought behind the first > patch in this series as the GbEth IP present in the RZ/G2L and other > Renesas SoCs has a very asymmetric capability (it can receive 8000 byte > frames but only transmit 1522 byte frames). > > If we explicitly do not wish to support this, that restriction should be > documented and then (maybe over time) handled uniformly for all network > drivers. > > I'm planning to submit v2 of this series shortly. Does the hardware support scatter/gather? How does supporting jumbo receive affect memory usage? Can you give the hardware a number of 2K buffers, and it will use one for a typical packet, and 4 for a jumbo frame? Andrew