On Thu, 2016-04-14 at 18:22 +0200, Phil Sutter wrote: > And those being invisible can be overridden using 'tc qd add', right? > AFAIR they're not listed because they don't properly register, so the > system doesn't care to override them. In this case we could change all > classful qdiscs to restore the default qdisc if a leaf qdisc is being > deleted instead of noop (which is probably not what the user wants > anyway).
Even if they properly register, they are not visible. Take a look at https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=95dc19299f741c986227ec33e23cbf9b3321f812 for some context. When a default pfifo is created on say a HTB class, you do not see it by default in a dump. If you have 100 HTB classes, HTB created 100 pfifo just fine, and it works, unless an admin tries to delete them maybe ;)
