Re: [PATCH v3 4/4] xen/console: reduce number of printouts in __printk_ratelimit()

[Jan Beulich <jbeulich@suse.com>]

On 15.07.2026 22:19, dmukhin@ford.com wrote:
> From: Denis Mukhin <dmukhin@ford.com> 
> 
> Fold several __putstr() calls into one around notification of how many
> messages have been rate-limited.
> 
> Not a functional change.
> 
> Signed-off-by: Denis Mukhin <dmukhin@ford.com>

Hmm, the upsides and downsides aren't being discussed at all. You're ...

> --- a/xen/drivers/char/console.c
> +++ b/xen/drivers/char/console.c
> @@ -1303,15 +1303,15 @@ bool __printk_ratelimit(unsigned int ratelimit_ms,
>          spin_unlock(&ratelimit_lock);
>          if ( lost )
>          {
> -            char lost_str[10];
> +            char msg[64];
> +
> +            snprintf(msg, sizeof(msg),
> +                     "printk: %u messages suppressed\n", lost);
>  
> -            snprintf(lost_str, sizeof(lost_str), "%u", lost);
>              /* console_lock may already be acquired by printk(). */
>              rspin_lock(&console_lock);
>              printk_start_of_line(CONSOLE_PREFIX);
> -            __putstr("printk: ");
> -            __putstr(lost_str);
> -            __putstr(" messages suppressed.\n");
> +            __putstr(msg);
>              rspin_unlock(&console_lock);
>          }
>          local_irq_restore(flags);

... trading slightly smaller code size + slightly better performance for
slightly bigger stack utilization. It's not entirely obvious that this is
a good deal.

Jan