Re: [patch] jiffies wraparound [Re: 2.1.125 Show stopper list: Draft]

Linus Torvalds (torvalds@transmeta.com)
Sat, 17 Oct 1998 15:49:41 -0700 (PDT)


On Sun, 18 Oct 1998, Alan Cox wrote:
> >
> > Quite frankly, considering the "jiffies" thing to be a show-stopper is
> > just ridiculous. It's not even on my radar, and I don't see this being a
> > 2.2 issue.
>
> I guess it depends on your agenda. An OS that has to be rebooted every
> 490 days isnt a very good embedded system large or small. "Please remember
> to reboot your building airconditioning control system about next august" ;)

Uhh.. Alan, I hate to tell you, but if nobody bothered to mention it or
make patches for it during the two and a half years of the 2.1.x series,
then it's a bit late now to say it's a showstopper.

It's a beauty wart, it's been there forever, and we know that machines
actually tend to survive it fine. So far I have _one_ person who has
actually complained about the wraparound, and his machine stayed up just
fine, he just complained about the fact that "uptime" said his machine had
been up for zero days.

I agree that there are probably drivers out there that get confused, and I
agree it needs to get fixed eventually, but "show stopper"? Nope.

As to embedded systems and rebooting: many of them are _designed_ to be
rebooted once a day. They do it not because they know that there's a
32-bit jiffy wraparound, but simply because the designers knew that there
were issues they _didn't_ know about. And felt happier putting in an
automatic watchdog timer.

The mars rover lived on to tell its tale only because it had an automatic
reboot sequence.

Building airconditioning, elevators etc are all supposed to have yearly
maintenance in places that care about them. And if they don't care about
them, why should we?

> View from on high noted, want me to take it off the list ?

Yup. But I don't mind it if somebody keeps a "warts" list around, in case
people decide to fix it at a time when I will accept patches..

Linus

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.rutgers.edu
Please read the FAQ at http://www.tux.org/lkml/