diff options
| author | Yicong Yang <yangyicong@hisilicon.com> | 2025-07-01 19:02:13 +0800 |
|---|---|---|
| committer | Will Deacon <will@kernel.org> | 2025-07-04 13:17:30 +0100 |
| commit | 60bc47b5a0b164082d448815d7db3066266aa3ed (patch) | |
| tree | 49037ceaa09b4317f10ba5a5c5139bd56f07b274 /kernel | |
| parent | Linux 6.16-rc1 (diff) | |
| download | linux-60bc47b5a0b164082d448815d7db3066266aa3ed.tar.gz linux-60bc47b5a0b164082d448815d7db3066266aa3ed.zip | |
watchdog/perf: Provide function for adjusting the event period
Architecture's using perf events for hard lockup detection needs to
convert the watchdog_thresh to the event's period, some architecture
for example arm64 perform this conversion using the CPU's maximum
frequency which will be acquired by cpufreq. However by the time
the lockup detector's initialized the cpufreq driver may not be
initialized, thus launch a watchdog with inaccurate period. Provide
a function hardlockup_detector_perf_adjust_period() to allowing
adjust the event period. Then architecture can update with more
accurate period if cpufreq is initialized.
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Yicong Yang <yangyicong@hisilicon.com>
Link: https://lore.kernel.org/r/20250701110214.27242-2-yangyicong@huawei.com
Signed-off-by: Will Deacon <will@kernel.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/watchdog_perf.c | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/kernel/watchdog_perf.c b/kernel/watchdog_perf.c index 75af12ff774e..9c58f5b4381d 100644 --- a/kernel/watchdog_perf.c +++ b/kernel/watchdog_perf.c @@ -187,6 +187,28 @@ void watchdog_hardlockup_disable(unsigned int cpu) } /** + * hardlockup_detector_perf_adjust_period - Adjust the event period due + * to current cpu frequency change + * @period: The target period to be set + */ +void hardlockup_detector_perf_adjust_period(u64 period) +{ + struct perf_event *event = this_cpu_read(watchdog_ev); + + if (!(watchdog_enabled & WATCHDOG_HARDLOCKUP_ENABLED)) + return; + + if (!event) + return; + + if (event->attr.sample_period == period) + return; + + if (perf_event_period(event, period)) + pr_err("failed to change period to %llu\n", period); +} + +/** * hardlockup_detector_perf_stop - Globally stop watchdog events * * Special interface for x86 to handle the perf HT bug. |