Hi,
On Fri, Jun 16, 2023 at 8:07 AM Petr Mladek [off-list ref] wrote:
There are four possible variants of hardlockup detectors:
+ buddy: available when SMP is set.
+ perf: available when HAVE_HARDLOCKUP_DETECTOR_PERF is set.
+ arch-specific: available when HAVE_HARDLOCKUP_DETECTOR_ARCH is set.
+ sparc64 special variant: available when HAVE_NMI_WATCHDOG is set
and HAVE_HARDLOCKUP_DETECTOR_ARCH is not set.
The check for the sparc64 variant is more complicated because
HAVE_NMI_WATCHDOG is used to #ifdef code used by both arch-specific
and sparc64 specific variant. Therefore it is automatically
selected with HAVE_HARDLOCKUP_DETECTOR_ARCH.
This complexity is partly hidden in HAVE_HARDLOCKUP_DETECTOR_NON_ARCH.
It reduces the size of some checks but it makes them harder to follow.
Finally, the other temporary variable HARDLOCKUP_DETECTOR_NON_ARCH
is used to re-compute HARDLOCKUP_DETECTOR_PERF/BUDDY when the global
HARDLOCKUP_DETECTOR switch is enabled/disabled.
Make the logic more straightforward by the following changes:
+ Better explain the role of HAVE_HARDLOCKUP_DETECTOR_ARCH and
HAVE_NMI_WATCHDOG in comments.
+ Add HAVE_HARDLOCKUP_DETECTOR_BUDDY so that there is separate
HAVE_* for all four hardlockup detector variants.
Use it in the other conditions instead of SMP. It makes it
clear that it is about the buddy detector.
+ Open code HAVE_HARDLOCKUP_DETECTOR_NON_ARCH in HARDLOCKUP_DETECTOR
and HARDLOCKUP_DETECTOR_PREFER_BUDDY. It helps to understand
the conditions between the four hardlockup detector variants.
+ Define the exact conditions when HARDLOCKUP_DETECTOR_PERF/BUDDY
can be enabled. It explains the dependency on the other
hardlockup detector variants.
Also it allows to remove HARDLOCKUP_DETECTOR_NON_ARCH by using "imply".
It triggers re-evaluating HARDLOCKUP_DETECTOR_PERF/BUDDY when
the global HARDLOCKUP_DETECTOR switch is changed.
+ Add dependency on HARDLOCKUP_DETECTOR so that the affected variables
disappear when the hardlockup detectors are disabled.
Another nice side effect is that HARDLOCKUP_DETECTOR_PREFER_BUDDY
value is not preserved when the global switch is disabled.
The user has to make the decision again when it gets re-enabled.
Signed-off-by: Petr Mladek <pmladek@suse.com>
---
arch/Kconfig | 23 +++++++++++++-----
lib/Kconfig.debug | 62 +++++++++++++++++++++++++++--------------------
2 files changed, 53 insertions(+), 32 deletions(-)
While I'd still paint the bikeshed a different color and organize the
dependencies a little differently, as discussed in your v1 post, this
is still OK w/ me.
Reviewed-by: Douglas Anderson <dianders@chromium.org>