Re: [PATCH v2 net-next 0/2] tcp: mmap: rework zerocopy receive

At the risk of further muddying the waters, there's another minor tweak
that could improve performance on certain workloads.  Currently you mmap()
a range for a given socket and then getsockopt() to receive.  If you made
it so you could mmap() something once for any number of sockets (by
mmapping /dev/misc/tcp_zero_receive or whatever), then the performance of
the getsockopt() bit would be identical, but you could release the mapping
for many sockets at once with only a single flush.  For some use cases,
this could be a big win.

You could also add this later easily enough, too.