Eric Dumazet <eric.duma...@gmail.com> wrote: > > If you prefer that, ok, but I don't see why we can't unify them behind > > a single layer? > > Well, for a start we do not use nf_brifge or secpath.
Then the extension framework isn't built and the result is exactly the same as before these patches: helpers turn into empty inline stubs. If its built, sk_buff size is reduced by up to one pointer, and the added one isn't initialised at allocation time. sk_buff layout with the extension patches is almost same as with XFRM=n BRIDGE_NF=n (because nf_bridge and sp pointers get removed), there is only one additional pointer at the end, not inited at alloc time. The other new member fills a hole. > XDP is all about not unifying because unifying has a cost. > > Do we really want to slow down the stack just because MPTCP is coming ? I don't want to slow down the stack. All places that gain a helper call do so instead of the nf_bridge/secpath one. They only expand into code if at least one of secpath or nf_bridge are built in. Both struct secpath and nf_bridge have their refcounts removed, so no additional reference counts are added. If you still think this is proposal is a bad idea, ok, let me know and I will stop working on this. MPTCP can then just add skb->cb2[], but neither nf_bridge nor secpath can use it. If not, I will send another iteration that just allocates the entire extension space if first extension is added, it simplifies allocation handling a little.
