Hitachi djprobe mechanism

[Andi Kleen]

> No practical solution has been elaborated for a fully preemptible kernel. Even
> walking on the talk list checking for potential iret pointers is not a good
> idea: If you have a stopped process that has its instruction pointer exactly in
> the wrong area, then you may wait forever.

You only look at runnable processes of course.

> Per cpu workqueue to make sure none is still in interrupt context would, I
> think, do the same as a non maskable IPI but without the busy looping.

Non maskable IPI? What for?

Somehow I have the impression you're trying to do things in the most
complicated imaginable way. But that's not how things in Linux
are done normally.

-Andi