netdev - Re: [RFC PATCH] virtio_net: XDP support for adjust

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <ec43c1a6-daf1-392a-8776-3f6597bea88e@redhat.com>
Date:   Wed, 4 Jan 2017 11:21:18 +0800
From:   Jason Wang <jasowang@...hat.com>
To:     John Fastabend <john.fastabend@...il.com>, mst@...hat.com
Cc:     john.r.fastabend@...el.com, netdev@...r.kernel.org,
        alexei.starovoitov@...il.com, daniel@...earbox.net
Subject: Re: [RFC PATCH] virtio_net: XDP support for adjust_head



On 2017年01月04日 00:54, John Fastabend wrote:
>>> +    /* Changing the headroom in buffers is a disruptive operation because
>>> +     * existing buffers must be flushed and reallocated. This will happen
>>> +     * when a xdp program is initially added or xdp is disabled by removing
>>> +     * the xdp program.
>>> +     */
>> We probably need reset the device here, but maybe Michale has more ideas. And if
>> we do this, another interesting thing to do is to disable EWMA and always use a
>> single page for each packet, this could almost eliminate linearizing.
> Well with normal MTU 1500 size we should not hit the linearizing case right?

My reply may be not clear, for 1500 I mean for small buffer only.

Thanks

>   The
> question is should we cap the MTU at GOOD_PACKET_LEN vs the current cap of
> (PAGE_SIZE - overhead).
>