To clarify a few things regarding that "debug" mess:
I will change systemd to not log to kmsg if journald is around when "debug" is specified. We will continue to log to kmsg during the early bootphase however als long as journald is not running yet. At that point there is simply no other option for that, because persistent storage is not available yet at that point and we need som way for people to get their logs out of the system, and early kmsg is the only way really, since it is hooked up with netconsole, serial tty, crashkernels, ... and all that other stuff.
I also believe that it is the right thing for the kernel to ratelimit whatever userspace sends it. For the same reason as we have to ratelimit all log streams in journald too, regardless where they come from. If you get a stream of logs from a 'differently priviliged' component then you need to rate limit it, that should be common sense. Of course I wish the ratelimiting applied is always configurable for the user, so that he can control how much and how soon things get dropped.
For me it is out of question though that systemd and other core os components should continue to parse the 'debug' kernel cmdline option, and increase their debug levels then. Generic options like that are supposed to be useful for real people, and there's a long history of options like that which influence both kernel and userspace (quiet, root=, ...). We are putting together an OS here after all, not just a kernel, and a kernel is just one component of the OS among many, and ultimately an implementation detail. We are writing an OS here for the general purpose, not just a toy for a clique of kernel developers. Moreover, there are individual kernel cmdline options for both the kernel itself and systemd to control just their log levels, and nothing else. so if you want finegrained control, you already have it, 'debug' is just the simple option that groups them all under a single oneshot option. It's the option an admin can specify which tells him why the system doesnt boot, regardless whether the kernel or systemd is at fault or any other part of the core os involved in boot. Thats simply userfriendly.
I do not appreciate all that talk from certain parts of the community that the systemd folks need to 'get tought a lesson'. That turns this into some kind of power game, which I am totally not interested in. Comparing us to Putin, or trying to bind merging of completely unrelated code to us doing whatever some kernel devs want (which is blackmail at worst, and childish at best, and childish we can be on our own enough, thanks) will just make us ignore you, and that's it. I prefer to deal with technical questions, and intimidation is not a technical question.
what the various news outlets wrote about all this is quite ridiculous. It's sad how badly these sites report, quite a shame.
And that is all.