Re: [RFC PATCH v2 11/14] x86/watchdog/hardlockup: Add an HPET-based hardlockup detector

[Peter Zijlstra]

On Wed, Feb 27, 2019 at 08:05:15AM -0800, Ricardo Neri wrote:
> diff --git a/arch/x86/include/asm/hpet.h b/arch/x86/include/asm/hpet.h
> index 4d559e0c746f..15dc3b576496 100644
> --- a/arch/x86/include/asm/hpet.h
> +++ b/arch/x86/include/asm/hpet.h
> @@ -123,12 +123,24 @@ struct hpet_hld_data {
>       u32             num;
>       u32             flags;
>       u64             ticks_per_second;
> +     u32             handling_cpu;
> +     struct cpumask  cpu_monitored_mask;
> +     struct msi_msg  msi_msg;
>  };

Please don't use struct cpumask unless you absolutely have to.

The above is better written as:


        struct hpet_hld_data {
                ...
                unsigned long cpumask[0];
        };

and allocated using:

        struct hpet_hld_data *hhd = kzalloc(sizeof(struct hpet_hld_data) + 
cpumask_size());

and used as:

        to_cpumask(hhd->cpumask);