Re: [PATCH v5 08/18] watchdog/hardlockup: Move perf hardlockup checking/panic to common watchdog.c

On Fri 2023-05-19 10:18:32, Douglas Anderson wrote:

The perf hardlockup detector works by looking at interrupt counts and
seeing if they change from run to run. The interrupt counts are
managed by the common watchdog code via its watchdog_timer_fn().

Currently the API between the perf detector and the common code is a
function: is_hardlockup(). When the hard lockup detector sees that
function return true then it handles printing out debug info and
inducing a panic if necessary.

Let's change the API a little bit in preparation for the buddy
hardlockup detector. The buddy hardlockup detector wants to print
nearly the same debug info and have nearly the same panic
behavior. That means we want to move all that code to the common
file. For now, the code in the common file will only be there if the
perf hardlockup detector is enabled, but eventually it will be
selected by a common config.

Right now, this _just_ moves the code from the perf detector file to
the common file and changes the names. It doesn't make the changes
that the buddy hardlockup detector will need and doesn't do any style
cleanups. A future patch will do cleanup to make it more obvious what
changed.

With the above, we no longer have any callers of is_hardlockup()
outside of the "watchdog.c" file, so we can remove it from the header,
make it static, and move it to the same "#ifdef" block as our new
watchdog_hardlockup_check(). While doing this, it can be noted that
even if no hardlockup detectors were configured the existing code used
to still have the code for counting/checking "hrtimer_interrupts" even
if the perf hardlockup detector wasn't configured. We didn't need to
do that, so move all the "hrtimer_interrupts" counting to only be
there if the perf hardlockup detector is configured as well.

This change is expected to be a no-op.

Signed-off-by: Douglas Anderson <dianders@chromium.org>

Reviewed-by: Petr Mladek <pmladek@suse.com>

Best Regards,
Petr

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