As Linus has stated, it looks like the merge window will happen over the holidays with 4.20 being released just before Christmas.
He is encouraging people to get pull requests in early, something some other maintainers have done already and/or have been doing regularly. In order to do that we have to freeze the net-next tree, and after some discussions with Daniel Borkmann, I've decided that we should freeze Thursday night, in PST timezone. It is my understanding that the bpf-next tree will also synchronize and freeze at this time as well. Please get your changes submitted in final form before Thursday night. Don't test me or be lazy, and if you don't make the cutoff you can submit in a couple weeks for the next merge window so don't worry about it so much. Thanks!