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 CA9B323775 for ; Mon, 19 Feb 2024 09:44:12 +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=1708335852; cv=none; b=PcGLLG/o1mcSqsHlXkNyXeMaJagf7jJtYxinEGhMxNwf1fGK7RTTP0aEVgae7sd1yP8+l5422AijXCSCBg+y6O8vcGVBtrkRIXUQpsWvmjbfUPNdS95gcSmLAfFuT7+kHRElqbW00/aJdYkImmdlauRIBs5Jp2b88tucxLqRp4g= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708335852; c=relaxed/simple; bh=VEhy19/wcpSsCp937fCoCnmrVRFEOwo2rekbY244/to=; h=Message-ID:Date:MIME-Version:Subject:To:References:Cc:From: In-Reply-To:Content-Type; b=UFqJroJTY874EnDVYBy9ogYSgVNCU+2PScCOp0rY0pOcVdKcV5EhlZHoEBfIc2JV/MuUtTG+wAl58TMz7sWFQYYzDSXxguCEKUrRq6ZPRqZvkX/lZBmX0Cdi6s6NBxQq1gJLGql/XzhKIBn3gkU6gpQdaCRN5EB+V0cZjZvD3XY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=VdHCUjgf; 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="VdHCUjgf" Received: by smtp.kernel.org (Postfix) with ESMTPSA id AABDEC43394; Mon, 19 Feb 2024 09:44:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1708335852; bh=VEhy19/wcpSsCp937fCoCnmrVRFEOwo2rekbY244/to=; h=Date:Subject:To:References:Cc:From:In-Reply-To:From; b=VdHCUjgfAOz6zSwmy6XcpwotkGkiJKBjOUNHVIwiZdd0jTWHnqzvwIgvhu6FwXKgF FTUv0tHMKZEyT9EhqEQPG9oE7Ta8OaK16ePyvwllDyAT7iE0kXN974YtlYTmmt5/dn EBa7AfDom84jl627N4Lx4Gb8/GtmXvMbk7v3LJIZiSENuWb42UZnSnypfD/QoM9yEC uL9WWksETr6rIHUatX4LL5OEe8LKetuiTBFU1XXRwtejm3y2nXHVxH46RYzkpopBdr ve6RAkrnZUFnALWQrKl6YUzmQ9KHWIbxjO1jH+njCyDNpbOcshG+x4XHjD8Mccx4c4 3fLckh36m+50Q== Message-ID: Date: Mon, 19 Feb 2024 10:44:10 +0100 Precedence: bulk X-Mailing-List: mptcp@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3 net-next 0/7] mptcp: implement TCP_NOTSENT_LOWAT support Content-Language: en-GB, fr-BE To: Paolo Abeni , Mat Martineau References: Cc: mptcp@lists.linux.dev From: Matthieu Baerts Autocrypt: addr=matttbe@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit Hi Paolo, Mat, On 16/02/2024 12:28, Paolo Abeni wrote: > Patch 6/7 does the magic, all the others are minor cleanup and fix of > buglet exposed by such feature. I'll push a paired pktdrill test. > > Note that this relies on the existing accounting for snd_nxt. As I > stated such accounting is not 110% accurate as it tracks the most recent > sequence number queued to any subflow, and not the actual sequence > number sent on the wire. > > I experimented a lot trying to implement the latter and in the end it > proved to be both "too complex" and "not necessary". > > The complexity raises from the need for additional lock and a lot of > refactory to introduce such protection without adding significant > overhead. Additionally, snd_nxt is currenly used and exposed with the > current semantic both eBPF and the internal packet scheduling. > Introducing a different tracking will still require us to keep the old > one. > > More interesting, a more accurate tracking could be not strictly > necessary: as the MPTCP protocol enqueues data to the subflows only up > the available send window, any enqueue data is sent on the wire > instantly, without any blocking operation short of a drop in the tx path > at the nft or TC layer. > > The individual patches changelog carry the gory details. > > Still sending a single series to outline the functional requirements, > even if the first 3 patches could land on mptcp-net directly. Thank you for the patches, and the reviews! Now in our tree (fixes for -net, and feat. for net-next): New patches for t/upstream-net and t/upstream: - d9b01cb9adc7: mptcp: push at DSS boundaries - 1ea124e2ca57: mptcp: fix snd_wnd initialization for passive socket - c64351cfe29e: mptcp: fix potential wake-up event loss - Results: 086d253b7038..9dcf86462a59 (export-net) - efe1cf277159: conflict in top-bases/t/DO-NOT-MERGE-git-markup-net-next - Results: 8de48203098c..4f7ce06a0f9e (export) New patches for t/upstream (only): - 232c91fcaf38: mptcp: cleanup writer wake-up - 1e762225d9b2: mptcp: avoid some duplicate code in socket option handling - 51913f3f330f: mptcp: implement TCP_NOTSENT_LOWAT support - eb5db737fdac: mptcp: cleanup SOL_TCP handling - Results: 4f7ce06a0f9e..f2fb9bec2195 (export) Cheers, Matt -- Sponsored by the NGI0 Core fund.