- Provide TUNABLE_INT() hooks for ktr_cpumask, ktr_mask, and ktr_verbose
so that they can be set from the loader by their respective sysctl names.
For example, to turn on KTR_INTR and KTR_PROC in ktr_mask, one could
stick 'debug.ktr.mask="0x1200"' in /boot/loader.conf.
commands have also been slightly updated as follows:
- Use ktr_idx to find the newest entry rather than walking the buffer
comparing timespecs. Timespecs are not always unique after the change
to use getnanotime(9).
- Add a new verbose setting. When the verbose setting is on, then the
timestamp is printed with each message. If KTR_EXTEND is on, then the
filename and line number are output as well. By default this option is
off. It can be turned on with the 'v' modifier passed to the 'tbuf'
and 'tall' commands. For the 'tnext' command, the 'v' modifier toggles
the verbose mode.
- Only display the cpu number for each message on SMP systems.
- Don't display anything for an empty entry that hasn't been used yet.
can lead to further panics.
- Call getnanotime() instead of nanotime() for the timestamp. nanotime()
is more precise, but it also calls into the timer code, which results
in mutex operations on the i386 arch. If KTR_LOCK is turned on, then
ktr_tracepoint() recurses on itself until it exhausts the kernel stack.
Eventually this should change to use get_cyclecount() instead, but that
can't happen if get_cyclecount() is calling nanotime() instead of
getnanotime().
function declared in kern_ktr.c. The only inline checks left are the
checks that compare KTR_COMPILE with the supplied mask and thus should
be optimized away into either nothing or a direct call to ktr_tracepoint().
- Move several KTR-related options to opt_ktr.h now that they are only
needed by kern_ktr.c and not by ktr.h.
- Add in the ktr_verbose functionality if KTR_EXTEND is turned on. If the
global variable 'ktr_verbose' is non-zero, then KTR messages will be
dumped to the console. This variable can be set by either kernel code
or via the 'debug.ktr_verbose' sysctl. It defaults to off unless the
KTR_VERBOSE kernel option is specified in which case it defaults to on.
This can be useful when the machine locks up spinning in a loop with
interrupts disabled as you might be able to see what it is doing when it
locks up.
Requested by: phk
