> Depends on how the socket buffer is being handled.  If we have the
> pending info sitting around in mbufs, this change won't do much.
> You're right that it won't save us anything.

> If however we copy the incoming packets into the buffer, we save an
> extra copy in the kernel.  Yes, we still have a copy to userland, but
> we have one less copy in the kernel.

But doesn't that require either (a) exposing *all* network traffic to
the userland process or (b) knowing at DMA buffer setup time (ie, well
in advance) which packets are destined for that particular connection?

Now, (a) may be acceptable for some special-case applications, but the
discussion I've seen makes this sound as though it's something intended
for general-purpose use.  And I think (b) is even less generally
suitable than (a) is....

Perhaps I'm misunderstanding something.

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