Re: wait until swapoff is *actually* finished (it returns too early)?
On Wed, Aug 21, 2024 at 08:39:37AM +0200, Erwan David wrote:
> On Wed, Aug 21, 2024 at 02:18:44AM CEST, Greg Wooledge <greg@wooledge.org> said:
> > On Tue, Aug 20, 2024 at 20:04:11 -0400, Roberto C. Sánchez wrote:
> > > sync && sync && sync && swapoff
> > >
> > > I couldn't tell why I have sync 3 times, but I know that it's how I've
> > > called swapoff since as far back as I can remember.
> >
> > Cargo cult. It was never useful to the best of my knowledge.
>
> Once upon a time, the sync command would return before the actual
> syscall where completed. Doing 3 times sync gave you a very high
> probability that the first one indeed completed all its writes.
I do remember one smart alec typing the following, he did not realise that
typing on separate lines was to slow him down:
sync;sync;sync
^P
H
^P on a PDP-11 console made it enter console state and 'H' then halted the
processor.
--
Alain Williams
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