From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pj2-f10.google.com (mail-pj2-f10.google.com [74.125.227.138]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D70A74D0CFB for ; Mon, 5 Oct 2026 16:52:11 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=74.125.227.138 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791219133; cv=none; b=uyCZwW6sFoP4dcMcqLLW8Qy0QBZzZh+pt+oQOLpTw7WAo6La48Za84u/sqaL49gBBk68icvBCvz0NMNDojKVWEZeHTOY+t6EatKOc/6R+toUD2Nruh54g7Wy/Gz1U0XwXLQ5HiN2JflBmKtaB/HoSusQvhHmir+itwESlwGWG/s= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791219133; c=relaxed/simple; bh=/tRm15v2eDHO+loamV84hQyUIYclpqiL/2I9jixRE6k=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=Uc9k0ruzyH2C5/CHG1SZGEZ1qCCNDc3xAcm+A/6Z5V1TzO2/XJHVKROT7As/Dul3cbT5aIOhQAaSnoUN+iXtCPEvDyrfVbJJLPvxo+phfcBqnGdcTva7kUfbsVi+7ueKxCWh7TLfTOfrRJBhEPRoveUEVhCdrch9dYK6VYN5EkI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=pbbmpGgO; arc=none smtp.client-ip=74.125.227.138 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="pbbmpGgO" Received: by mail-pj2-f10.google.com with SMTP id d9443c01a7336-2dd9bce707bso8490115ad.1 for ; Mon, 05 Oct 2026 09:52:11 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1791219131; x=1791823931; darn=vger.kernel.org; h=in-reply-to:content-transfer-encoding:content-disposition :content-type:mime-version:references:message-id:subject:cc:to:from :date:from:to:cc:subject:date:message-id:reply-to:content-type; bh=0Ml/WHArCmzzGX3zR0T2czoQ4pKZKMdyG5OJbl9EXA8=; b=pbbmpGgO5iRj7JGDznK88nBraAxrqQ5X6sHI5PiSenjpQy8uK4emegnE+ROD1z7APm zJZ/406PYtFGWr6L3fMWI2/v8ZKrZcHjL3vpO0IyQmXZWy6oHlWXolXs+Zq4kvUrBAys TBNV1oGAi4HRVWNJbLARt+d9Eu/Ft/ETjIeGee2HK4F7hmlOARFh5g+P1FtZ3gDyz6Lv Coi3Kqgp2vt10/QzhSN4jMbCqEgr0dyNwW3xOsirh0STCyMtNkPo4qXJlmm5s7lpmAZ2 gsj7DlO/2GibNPe7Rdrbjd8VX/feM6mGIT2oPR6cB4swQ2egQkcNMWZa+aSoKvAUx/5s 2MMQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20260707; t=1791219131; x=1791823931; h=in-reply-to:content-transfer-encoding:content-disposition :content-type:mime-version:references:message-id:subject:cc:to:from :date:x-gm-gg:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to:content-type; bh=0Ml/WHArCmzzGX3zR0T2czoQ4pKZKMdyG5OJbl9EXA8=; b=OPQI+BzKf8yuxxNnsZ82pvzzDXdwuDSXdRh/9/ilKqG+egK4seOHk6lrEOCMaKUxLS UmsK4i0Fqls4JAOpkR5S+GlIBqp/tS5IQhfEC9bghau0B29DFIKTL/xbGkduJh+ovJLR rJ1NIfYY+KLG5Ryv6np+lpAXVGbjtCmSCf4rRUiBRuwKI9jRjHOJSOHKwwGu+3muhlYU SyrgZL8TXKjkX8GquQPo7ugw6Z3cPuRbruh77Sf6vGXsK61em3kJTAtMdY2DSomFyFUn XLvmgWIDjvYkLx5VTKHgy08pjwCMZWtIS10jXl9etTIODb4HpE9OT8qTIvNGombsv25S btow== X-Forwarded-Encrypted: i=1; AKwUvBwz4bixD45hP3jET07BIEWEd9dd1qPI67gcPSQIi/pTlVysuy2RKbkjffesFvnJqQABhZCGm9c=@vger.kernel.org X-Gm-Message-State: AFq9FYIV9STlCuw3u0XSgqexZxi0RalAGhU651oj6w2UfmdenaCx3yjO mQTjztDsby65Z5IEwy0tg+o5oXnUrMp57UDy8T4PoYFICbPMdhIFh4LZ X-Gm-Gg: AYBFou3gaN9Wdg8NkyCO6bEnx+9R4T6NvQF8fZ+ITt8iq7izMVpoyloq0fcN4T+bkSo bBJgexQxwciPPkFrLZ6je0sIvj7clzIoaxBLd7YmnY0EGyzle15QtK4VSNEW2ZHoDi2qT/zjJUH yR9fGH3jWhpiNwwVntZDMcY84pm9VDYSzuQUt3/259iWEdYTjvF0HmgHD1nbh4DfW2lpj6t98/R b6NKvGaQ4Ty6XTG0K1AGfb4BN7K4O5X2xQtw7Iyha8+OTtkMubdbHeO4SSBEM0WRfwyYiIvGkq6 qAMz5hDmsag29tVoU3SjSalo9F3RhEnkCPVU0QBf4S+YL6aJkU9cQu7mEuW/zY0yJPzSm7VdG62 7ceV552GTGUanl5fFy5yNZ0b84uKKzlAEm+blT0LkXhNDSfwnjtWh4STfR/SLburASq9YwJDsSF pdME+/cgq0XFVEeCN6k1Q0eyJJ/ItYsmeeaCZOTaUZp9F9RJE2Y5jzPJ2ybd/zkH4d X-Received: by 2002:a17:902:d2c4:b0:2df:a4d8:57ad with SMTP id d9443c01a7336-2e49b699f84mr98443455ad.72.1791219131179; Mon, 05 Oct 2026 09:52:11 -0700 (PDT) Received: from localhost ([2a03:2880:2ff:4d::]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-2e5a5f001d9sm10692365ad.79.2026.10.05.09.52.10 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 05 Oct 2026 09:52:10 -0700 (PDT) Date: Mon, 5 Oct 2026 09:52:05 -0700 From: Stanislav Fomichev To: =?utf-8?B?QmrDtnJuIFTDtnBlbA==?= Cc: Magnus Karlsson , Maciej Fijalkowski , Stanislav Fomichev , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman , Jonathan Corbet , Shuah Khan , Randy Dunlap , Alexander Duyck , kernel-team@meta.com, Andrew Lunn , Jesper Dangaard Brouer , Ilias Apalodimas , Alexei Starovoitov , Daniel Borkmann , John Fastabend , Pavel Begunkov , Jens Axboe , Andrii Nakryiko , Eduard Zingerman , Kumar Kartikeya Dwivedi , Martin KaFai Lau , Song Liu , Yonghong Song , Jiri Olsa , Emil Tsalapatis , Ihor Solodrai , netdev@vger.kernel.org, bpf@vger.kernel.org, io-uring@vger.kernel.org, "Mike Marciniszyn (Meta)" , Weiming Shi , Nikolay Aleksandrov , David Wei , Alexander Lobakin , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, Mina Almasry Subject: Re: [RFC net-next 04/15] net: Let memory providers set RX buffer headroom Message-ID: References: <20261002190018.696925-1-bjorn@kernel.org> <20261002190018.696925-5-bjorn@kernel.org> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20261002190018.696925-5-bjorn@kernel.org> On 10/02, Björn Töpel wrote: > AF_XDP lets userspace choose a headroom in front of the packet data > in each UMEM chunk, and the kernel adds XDP_PACKET_HEADROOM to it. A > driver whose buffers come from an AF_XDP memory provider must put > packets after this headroom. The driver sees only the page pool, so > it has no generic way to learn the value, and nothing checks that > the driver supports it. > > Add rx_headroom to the provider parameters and to the queue > configuration. It is the full headroom, including > XDP_PACKET_HEADROOM; zero means the driver default. Add > QCFG_RX_HEADROOM. A provider that sets a headroom can only be > installed on a queue that supports it; otherwise the install fails > with -EOPNOTSUPP. The driver checks the value with the rest of the > queue configuration. > > Signed-off-by: Björn Töpel This is also a bit confusing to read on its own. Do we not need to convert existing users? The next patch does not seem to use this new rx_headroom?