Re: [PATCH v3 2/4] xen/console: correct leaky-bucket rate limiter

[Jan Beulich <jbeulich@xxxxxxxx>]

On 15.07.2026 22:19, dmukhin@xxxxxxxx wrote:
> --- a/xen/drivers/char/console.c
> +++ b/xen/drivers/char/console.c
> @@ -1274,21 +1274,26 @@ bool __printk_ratelimit(unsigned int ratelimit_ms,
>                          unsigned int ratelimit_burst)
>  {
>      static DEFINE_SPINLOCK(ratelimit_lock);
> -    static unsigned long toks = 10 * 5 * 1000;
> -    static unsigned long last_msg;
> +    static unsigned long long toks, last_msg;

Along the lines of what Teddy said, I question the need to widen the variables.

>      static unsigned int missed;
> +    unsigned long long now, limit;
>      unsigned long flags;
> -    unsigned long long now = NOW(); /* ns */
> -    unsigned long ms;
> +    s_time_t ms;

This is the type to use for e.g. NOW() return values; it isn't ...

> -    do_div(now, 1000000);
> -    ms = (unsigned long)now;
> +    if ( !ratelimit_burst || !ratelimit_burst )
> +        return true;
> +
> +    limit = min(ratelimit_burst * ratelimit_ms, UINT_MAX);
> +    if ( !toks )
> +        toks = limit;
> +
> +    now = NOW(); /* ns */
> +    ms = do_div(now, MILLISECS(1));

... a type to hold a millisecond granularity value.

Jan