From: Claudio Jeker <cjeker@diehard.n-r-g.com>
Subject: Re: Remove last callers of the lbolt sleep channel
To: Vitaliy Makkoveev <mvs@openbsd.org>
Cc: Tim Leslie <tleslie@protonmail.com>, "tech@openbsd.org" <tech@openbsd.org>
Date: Wed, 24 Sep 2025 20:26:12 +0200

On Wed, Sep 24, 2025 at 08:07:29PM +0300, Vitaliy Makkoveev wrote:
> On Wed, Sep 24, 2025 at 04:20:08PM +0000, Tim Leslie wrote:
> > > > So I prefer to use `nowake', because this 100% exclude the fallout from
> > > > current or hypothetical newly introduced wakeup(pr->ps_pgrp).
> > > 
> > > 
> > > I agree with this. Replacing this with 'nowake' is the right way since
> > > only the 1sec timer should wake up these ttysleeps.
> > 
> > Updated diff below.
> > 
> > Tim
> > 
> 
> Since you added ttysleep_nsec() declaration to sys/tty.h, you don't need
> this declaration in kern/tty.c. With this fix this diff is ok by mvs.
> 
> I will commit it by myself unless someone has objections or commit it by
> himself.

OK claudio@ with your removal of the extra ttysleep_nsec() prototype.
 
> > --
> > 
> > 
> > 
> > diff --git a/sys/kern/sched_bsd.c b/sys/kern/sched_bsd.c
> > --- a/sys/kern/sched_bsd.c
> > +++ b/sys/kern/sched_bsd.c
> > @@ -55,7 +55,6 @@
> >  #endif
> >  
> >  uint64_t roundrobin_period;	/* [I] roundrobin period (ns) */
> > -int	lbolt;			/* once a second sleep address */
> >  
> >  struct mutex sched_lock;
> >  
> > @@ -282,7 +281,6 @@ schedcpu(void *unused)
> >  		}
> >  		SCHED_UNLOCK();
> >  	}
> > -	wakeup(&lbolt);
> >  	timeout_add_sec(&to, 1);
> >  }
> >  
> > diff --git a/sys/kern/tty.c b/sys/kern/tty.c
> > --- a/sys/kern/tty.c
> > +++ b/sys/kern/tty.c
> > @@ -747,8 +747,8 @@ ttioctl(struct tty *tp, u_long cmd, caddr_t data, int flag, struct proc *p)
> >  			if (pr->ps_pgrp->pg_jobc == 0)
> >  				return (EIO);
> >  			pgsignal(pr->ps_pgrp, SIGTTOU, 1);
> > -			error = ttysleep(tp, &lbolt, TTOPRI | PCATCH,
> > -			    ttybg);
> > +			error = ttysleep_nsec(tp, &nowake, TTOPRI | PCATCH,
> > +				ttybg, SEC_TO_NSEC(1));
> >  			if (error)
> >  				return (error);
> >  		}
> > @@ -1515,7 +1515,8 @@ loop:	lflag = tp->t_lflag;
> >  			goto out;
> >  		}
> >  		pgsignal(pr->ps_pgrp, SIGTTIN, 1);
> > -		error = ttysleep(tp, &lbolt, TTIPRI | PCATCH, ttybg);
> > +		error = ttysleep_nsec(tp, &nowake, TTIPRI | PCATCH, ttybg, 
> > +			SEC_TO_NSEC(1));
> >  		if (error)
> >  			goto out;
> >  		goto loop;
> > @@ -1613,8 +1614,8 @@ read:
> >  		    ISSET(lflag, IEXTEN | ISIG) == (IEXTEN | ISIG)) {
> >  			pgsignal(tp->t_pgrp, SIGTSTP, 1);
> >  			if (first) {
> > -				error = ttysleep(tp, &lbolt, TTIPRI | PCATCH,
> > -				    ttybg);
> > +				error = ttysleep_nsec(tp, &nowake, TTIPRI | PCATCH, 
> > +					ttybg, SEC_TO_NSEC(1));
> >  				if (error)
> >  					break;
> >  				goto loop;
> > @@ -1765,7 +1766,8 @@ loop:
> >  			goto out;
> >  		}
> >  		pgsignal(pr->ps_pgrp, SIGTTOU, 1);
> > -		error = ttysleep(tp, &lbolt, TTIPRI | PCATCH, ttybg);
> > +		error = ttysleep_nsec(tp, &nowake, TTIPRI | PCATCH, ttybg, 
> > +			SEC_TO_NSEC(1));
> >  		if (error)
> >  			goto out;
> >  		goto loop;
> > diff --git a/sys/kern/tty_pty.c b/sys/kern/tty_pty.c
> > --- a/sys/kern/tty_pty.c
> > +++ b/sys/kern/tty_pty.c
> > @@ -294,7 +294,8 @@ again:
> >  			    pr->ps_flags & PS_PPWAIT)
> >  				return (EIO);
> >  			pgsignal(pr->ps_pgrp, SIGTTIN, 1);
> > -			error = ttysleep(tp, &lbolt, TTIPRI | PCATCH, ttybg);
> > +			error = ttysleep_nsec(tp, &nowake, TTIPRI | PCATCH, 
> > +				ttybg, SEC_TO_NSEC(1));
> >  			if (error)
> >  				return (error);
> >  		}
> > diff --git a/sys/sys/kernel.h b/sys/sys/kernel.h
> > --- a/sys/sys/kernel.h
> > +++ b/sys/sys/kernel.h
> > @@ -55,7 +55,6 @@ extern int ticks;		/* # of hardclock ticks */
> >  extern int hz;			/* system clock's frequency */
> >  extern int stathz;		/* statistics clock's frequency */
> >  extern int profhz;		/* profiling clock's frequency */
> > -extern int lbolt;		/* once a second sleep address */
> >  
> >  #ifndef HZ
> >  #define HZ 100
> > diff --git a/sys/sys/tty.h b/sys/sys/tty.h
> > --- a/sys/sys/tty.h
> > +++ b/sys/sys/tty.h
> > @@ -290,6 +290,7 @@ void	 ttypend(struct tty *tp);
> >  int	 ttyretype(struct tty *tp);
> >  int	 ttyrub(int c, struct tty *tp);
> >  int	 ttysleep(struct tty *tp, void *chan, int pri, char *wmesg);
> > +int	 ttysleep_nsec(struct tty *, void *, int, char *, uint64_t);
> >  int	 ttywait(struct tty *tp);
> >  int	 ttywflush(struct tty *tp);
> >  void	 ttytstamp(struct tty *tp, int octs, int ncts, int odcd, int ndcd);
> > 
> 

-- 
:wq Claudio