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

[dmukhin@ford.com]

On Thu, Jul 16, 2026 at 05:49:35PM +0200, Jan Beulich wrote:
> 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.

Thanks for the feedback!
I will drop that patch from the series.