Re: wait until swapoff is *actually* finished (it returns too early)?
On Thu, Aug 22, 2024 at 11:45 AM David Wright <deblis@lionunicorn.co.uk> wrote:
> I'm not convinced. Finding out what needs copying back and locating
> somewhere to put it is AIUI a slow process. What's much faster is
> when processes themselves demand something be paged back in from
> swap. I think there are "tricks" available to cause that to occur,
> thus speeding up swapoff.
Exactly. In my experience, running swapoff(8) _will_ take a long time
if the swap area has a lot of content. It will block until everything
is moved out.
What I think we are seeing here is that phase has finished, but the
kernel has not yet notified the backing store that it is no longer
used. Though that is just a WAG.
mrc
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