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From:   Magnus Karlsson <magnus.karlsson@gmail.com>
Date:   Wed, 31 Mar 2021 11:44:45 +0200
Message-ID: <CAJ8uoz2UNABjfpvHOopzvRfW4RJGSS2P=0MUZRkyg-e+S1OdHA@mail.gmail.com>
Subject: Re: [PATCH bpf-next 0/2] xsk: introduce generic almost-zerocopy xmit
To:     Alexander Lobakin <alobakin@pm.me>
Cc:     Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Xuan Zhuo <xuanzhuo@linux.alibaba.com>,
        =?UTF-8?B?QmrDtnJuIFTDtnBlbA==?= <bjorn@kernel.org>,
        Magnus Karlsson <magnus.karlsson@intel.com>,
        Jonathan Lemon <jonathan.lemon@gmail.com>,
        "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>,
        Jesper Dangaard Brouer <hawk@kernel.org>,
        John Fastabend <john.fastabend@gmail.com>,
        Andrii Nakryiko <andrii@kernel.org>,
        Martin KaFai Lau <kafai@fb.com>,
        Song Liu <songliubraving@fb.com>, Yonghong Song <yhs@fb.com>,
        KP Singh <kpsingh@kernel.org>,
        Network Development <netdev@vger.kernel.org>,
        bpf <bpf@vger.kernel.org>,
        open list <linux-kernel@vger.kernel.org>
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On Wed, Mar 31, 2021 at 1:17 AM Alexander Lobakin <alobakin@pm.me> wrote:
>
> This series is based on the exceptional generic zerocopy xmit logics
> initially introduced by Xuan Zhuo. It extends it the way that it
> could cover all the sane drivers, not only the ones that are capable
> of xmitting skbs with no linear space.
>
> The first patch is a random while-we-are-here improvement over
> full-copy path, and the second is the main course. See the individual
> commit messages for the details.
>
> The original (full-zerocopy) path is still here and still generally
> faster, but for now it seems like virtio_net will remain the only
> user of it, at least for a considerable period of time.
>
> Alexander Lobakin (2):
>   xsk: speed-up generic full-copy xmit
>   xsk: introduce generic almost-zerocopy xmit
>
>  net/xdp/xsk.c | 33 +++++++++++++++++++++++----------
>  1 file changed, 23 insertions(+), 10 deletions(-)
>
> --
> Well, this is untested. I currently don't have an access to my setup
> and is bound by moving to another country, but as I don't know for
> sure at the moment when I'll get back to work on the kernel next time,
> I found it worthy to publish this now -- if any further changes will
> be required when I already will be out-of-sight, maybe someone could
> carry on to make a another revision and so on (I'm still here for any
> questions, comments, reviews and improvements till the end of this
> week).
> But this *should* work with all the sane drivers. If a particular
> one won't handle this, it's likely ill.

Thanks Alexander. I will take your patches for a spin on a couple of
NICs and get back to you, though it will be next week due to holidays
where I am based.

> --
> 2.31.1
>
>