Re: [PATCH net-next] kcm: do not attach sockets if sk_user_data is already used

On Thu, 2018-01-18 at 11:26 -0800, Tom Herbert wrote:

On Thu, Jan 18, 2018 at 10:08 AM, Eric Dumazet [off-list ref] wrote:

quoted

On Thu, 2018-01-18 at 09:46 -0800, Tom Herbert wrote:

quoted

Then that's increasing the udp_sock structure size for a narrow use
case which will get push back. I think it's going to be better to
stick with one sock pointer. We could maybe redefine sk_user_data as a
pointer to an allocated structure or array so it can hold multiple
user_data pointers (in lieu of chaining).

We do not have a lot of UDP sockets per host, I do not believe it
should be a problem adding stuff in them.

Eric,

Is QUIC using unconnected sockets then?

Server side is using a bunch of unconnected sockets, usually one per
cpu.

Note that UDP stack has no 4-tuple proper support yet, and even if it
had, extra memory costs would be huge on servers handling millions of
flows.