Re: [Q/RFC] BPF use in broader scope

Li Yu <raise.sail@xxxxxxxxx> · Fri, 11 May 2012 15:06:42 +0800

于 2012年05月11日 14:22, Jiri Pirko 写道:

Fri, May 11, 2012 at 04:41:31AM CEST, raise.sail@xxxxxxxxx wrote:

于 2012年03月29日 17:31, Jiri Pirko 写道:

Thu, Mar 29, 2012 at 10:45:32AM CEST, eric.dumazet@xxxxxxxxx wrote:

On Thu, 2012-03-29 at 10:31 +0200, Jiri Pirko wrote:

Thu, Mar 29, 2012 at 10:02:25AM CEST, eric.dumazet@xxxxxxxxx wrote:

On Thu, 2012-03-29 at 09:54 +0200, Jiri Pirko wrote:

Yep, I'm aware. I must admit that the JIT code scares me a litte :(

If you add a new XOR instruction in interpreter only, JIT compiler will
automatically aborts, so no risk.

Each arch maintainer will add the support for the new instructions as
separate patches.

So you can focus on net/core/filter.c file only.

Ok - I can do this for 2). But for 3) JITs need to be modified. So I
would like to kindly ask you and Matt if you can do this modification so
bpf_func takes pointer to mem (scratch store) as second parameter. I'm
sure it's very easy for you to do.

I am not sure why you want this.

This adds register pressure (at least for x86) ...

Well I think that there would become handy to be able to pass some data
to bpf_func (other than skb). But it's just an idea.

Hi, Jiri Pirko, any progress of extended BPF? :)

I am interesting in 3) much. For my requirements,
it just only need BPF has ability to handle arbitrary
"pre-filled memory area", but not handle both a skb and
such a memory area at same time, so I think that register
pressure should not be become the performance bottleneck
here.

Otherwise, I must construct a fake sk_buff to execute filter
feature, it is ugly, isn't it?

I guess that Nuno Martins's requirements also are similar.

And, I also would like join this project, if you need.

For my needs it turned out I do not need pre-filled memory. So I dropped
that point.

Oops, I may try to work on this, would you like send
a copy of your sk-unattached filters patch to me ?
I think that it is a good start.

Thanks for your time.

Yu

Thanks

Yu

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