dtrace: stop using eventhandlers for the part compiled into the kernel

[mjg]

Summary

Side note is that allocations sizes seem also out of whack, will be sorted out separately.

Duplication in creation of proc/thread0 will have to be sorted out as well but that's beyond the scope.

[kib]

I am fine with conversion.

What surprises me is that just the presence of the hooks implies mallocs.

That said, why not piggy-back dtrace memory on struct thread, as we already have the scheduler data placed that way, see sched_sizeof_thread() and sched_sizeof_proc(). Just put one more addend into the zone creation size argument.

sys/kern/kern_dtrace.c

87 ↗

(On Diff #79844)

(void) while you are there

[markj]

sys/kern/kern_proc.c

68 ↗

(On Diff #79844)

If we are going to unconditionally include this header, it would be better to define the hooks for both KDTRACE_HOOKS and !KDTRACE_HOOKS, to avoid further polluting the code with ifdefs.

[mjg]

threads are NOFREE so this would add more memory which can't be reclaimed until reboot