Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
MIME-Version: 1.0
References: <20200911143022.414783-1-nicolas.rybowski@tessares.net> <20200911143022.414783-2-nicolas.rybowski@tessares.net>
In-Reply-To: <20200911143022.414783-2-nicolas.rybowski@tessares.net>
From:   Song Liu <song@kernel.org>
Date:   Mon, 14 Sep 2020 13:52:24 -0700
Message-ID: <CAPhsuW4xqPD641gHAs7GjhmW7SANMhz75VKbP02Xyja9CnpZ-g@mail.gmail.com>
Subject: Re: [PATCH bpf-next v2 2/5] mptcp: attach subflow socket to parent cgroup
To:     Nicolas Rybowski <nicolas.rybowski@tessares.net>
Cc:     Mat Martineau <mathew.j.martineau@linux.intel.com>,
        Matthieu Baerts <matthieu.baerts@tessares.net>,
        "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>,
        Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Martin KaFai Lau <kafai@fb.com>,
        Song Liu <songliubraving@fb.com>, Yonghong Song <yhs@fb.com>,
        Andrii Nakryiko <andriin@fb.com>,
        John Fastabend <john.fastabend@gmail.com>,
        KP Singh <kpsingh@chromium.org>,
        Paolo Abeni <pabeni@redhat.com>,
        Networking <netdev@vger.kernel.org>, mptcp@lists.01.org,
        open list <linux-kernel@vger.kernel.org>,
        bpf <bpf@vger.kernel.org>
Content-Type: text/plain; charset="UTF-8"
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Fri, Sep 11, 2020 at 9:43 AM Nicolas Rybowski
<nicolas.rybowski@tessares.net> wrote:
>
> It has been observed that the kernel sockets created for the subflows
> (except the first one) are not in the same cgroup as their parents.
> That's because the additional subflows are created by kernel workers.
>
> This is a problem with eBPF programs attached to the parent's
> cgroup won't be executed for the children. But also with any other features
> of CGroup linked to a sk.
>
> This patch fixes this behaviour.
>
> As the subflow sockets are created by the kernel, we can't use
> 'mem_cgroup_sk_alloc' because of the current context being the one of the
> kworker. This is why we have to do low level memcg manipulation, if
> required.
>
> Suggested-by: Matthieu Baerts <matthieu.baerts@tessares.net>
> Suggested-by: Paolo Abeni <pabeni@redhat.com>
> Acked-by: Matthieu Baerts <matthieu.baerts@tessares.net>
> Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
> Signed-off-by: Nicolas Rybowski <nicolas.rybowski@tessares.net>

Acked-by: Song Liu <songliubraving@fb.com>

[...]