Re: Does wscons use compat syscalls to switch sessions

[Paul Goyette <paul%vps1.whooppee.com@localhost>]

Yes, it sounds very familiar.

On Sun, 18 Oct 2015, Valery Ushakov wrote:

> On Sun, Oct 18, 2015 at 11:03:37 +0800, Paul Goyette wrote:
>
> > I just noticed that when switching console sessions from my X display
> > (on ttyE4) to the console session (on ttyE0), the system auto-loads the
> > "compat" kernel module.
> >
> > Is this expected?  normal?  Shouldn't all "current" production code be
> > using "current" syscalls and/or ioctls?
>
> This might be (haven't looked) the same problem I complained about
> some time ago on tech-kern:
>
> http://mail-index.netbsd.org/tech-kern/2013/12/15/msg016327.html
>
> On Sun, Dec 15, 2013 at 15:35:01 +0400, Valery Ushakov wrote:
>
> > Date: Sun, 15 Dec 2013 15:35:01 +0400
> > From: Valery Ushakov <uwe%stderr.spb.ru@localhost>
> > Subject: Compat module auto-bounce
> > To: tech-kern%netbsd.org@localhost
> >
> > ttioctl() in sys/tty.c ends with doing
> >
> >     (void)module_autoload("compat", MODULE_CLASS_ANY);
> >
> > for ioctls that it doesn't know about.  This causes compat module to
> > auto-bounce in and out a lot.  Note that this happens even for
> > up-to-date userland that doesn't need compat code.  E.g. ttyname(3)
> > uses TIOCPTSNAME which ttioctl() doesn't handle.  Running vi on
> > console seems to cause compat.mod to be autoloaded twice.
> >
> > This seems rather wasteful.
>
> -uwe

+------------------+--------------------------+-------------------------+
| Paul Goyette     | PGP Key fingerprint:     | E-mail addresses:       |
| (Retired)        | FA29 0E3B 35AF E8AE 6651 | paul at whooppee.com    |
| Kernel Developer | 0786 F758 55DE 53BA 7731 | pgoyette at netbsd.org  |
+------------------+--------------------------+-------------------------+