On Tue, Apr 13 2021 at 21:36, Paul E. McKenney wrote:
> diff --git a/arch/x86/kernel/kvmclock.c b/arch/x86/kernel/kvmclock.c
> index 1fc0962c89c0..97eeaf164296 100644
> --- a/arch/x86/kernel/kvmclock.c
> +++ b/arch/x86/kernel/kvmclock.c
> @@ -169,7 +169,7 @@ struct clocksource kvm_clock = {
> .read = kvm_clock_get_cycles,
> .rating = 400,
> .mask = CLOCKSOURCE_MASK(64),
> - .flags = CLOCK_SOURCE_IS_CONTINUOUS,
> + .flags = CLOCK_SOURCE_IS_CONTINUOUS | CLOCK_SOURCE_VERIFY_PERCPU,
kvm_clock is not marked with CLOCK_SOURCE_MUST_VERIFY, so what's the
point of adding this here? It's not subject to be monitored by the
watchdog muck.
> diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c
> index f70dffc2771f..56289170753c 100644
> --- a/arch/x86/kernel/tsc.c
> +++ b/arch/x86/kernel/tsc.c
> @@ -1151,7 +1151,8 @@ static struct clocksource clocksource_tsc = {
> .mask = CLOCKSOURCE_MASK(64),
> .flags = CLOCK_SOURCE_IS_CONTINUOUS |
> CLOCK_SOURCE_VALID_FOR_HRES |
> - CLOCK_SOURCE_MUST_VERIFY,
> + CLOCK_SOURCE_MUST_VERIFY |
> + CLOCK_SOURCE_VERIFY_PERCPU,
While this one is part of the horror show.
> +static u64 csnow_mid;
> +static cpumask_t cpus_ahead;
> +static cpumask_t cpus_behind;
> +
> +static void clocksource_verify_one_cpu(void *csin)
> +{
> + struct clocksource *cs = (struct clocksource *)csin;
> +
> + csnow_mid = cs->read(cs);
> +}
> +
> +static void clocksource_verify_percpu(struct clocksource *cs)
> +{
> + int64_t cs_nsec, cs_nsec_max, cs_nsec_min;
> + u64 csnow_begin, csnow_end;
> + bool firsttime = 1;
> + int testcpu;
> + s64 delta;
> + int cpu;
int testcpu, cpu; :)
