reparenting

You can solve this with a cgroup/namespacing/prctls to control orphan reparenting, but that's super hard to get right.

The author has identified the issue to be memcg reparenting causing a spike in CPU usage.

So the workaround ends up being impersonating another non-reparenting WM, for instance Sun's Looking Glass.

The zombie memcg problem is not unique to cgroup v2, but reparenting is fairly recent.

And then it's not even in the doc yet, you have to go find your cursor, find the doc element the cursor is in, and only then can you insert content via a reparenting operation.

Arbitrary nested tree reparenting can be a nightmare.

> Reparenting is needed for standard Unix utilities that want to run in the background.

Most Java distributions have the ability to work with non-reparenting WM's, but they detect it based on the window manager name.

I can't play games while using Xmonad since the games don't play nicely with non-reparenting window managers.

We couldn't figure out how to reparent a slave without completely re-cloning it from the new parent, even though it was completely up to date from the authoritative master at the time of the reparenting.

An example that matters for window managers would be complex window reparenting policies or input grabs, but that's a little less descriptive of the core concept I was trying to get across.

Of course there were some things you could change on the fly (like the default menu class, except that if apps cached instances of menus instead of recreating them, they would not change), but you could not redefine the window frames on the fly since they already were created, and reparenting the clients into new frames wasn't trivial.

I think what I did falls under the umbrella of “reparenting your inner child” if you want to research more.

But all of this is "purely computational." Imagine implementing Jujutsu's rebase command; it is just a trivial reparenting of some graph nodes, something an amateur programmer could do.

The only issue is with certain java-based applications such as PyCharm or Arudino IDE, in which sometimes the windows aren't drawn correctly due to the JVM not playing nicely with "non-reparenting" window managers (such as i3).

Reparenting is needed for standard Unix utilities that want to run in the background (especially in an interactive shell).

Reparenting mostly solves a problem with zombie memcg, where the memcg lingers because some resource is still charged to it.

Reparenting, of course, is not needed for long-running services/daemons, as demonstrated by daemontools, runit, s6, Upstart, systemd, etc.