Re: leaked swap?

On March 18, 2019 8:20:35 AM PDT, Andriy Gapon <avg_at_FreeBSD.org> wrote:
>
>First, a note that this was observed on a system that runs a fairly old
>current
>(~ 1 year old) with a fairly long uptime (> 6 months).
>I noticed that the system was nearly out of memory, 98% of swap was in
>use,
>there was less than 1 GB of free memory, several GBs of each of active,
>inactive
>and laundry memory, and many GBs of wired (mostly ZFS).
>I decided to pro-actively reboot the system, but to speed that up I put
>the
>system to the single-user mode (via shutdown) and then back to
>multi-user. So,
>there was no real hardware reboot and the kernel kept running. 
>However, all
>userland processes were terminated.
>
>To my surprise, even while in the single-user mode the swap utilization
>didn't
>go below 70%.  Also, laundry memory remained in multi-GB area, but
>let's ignore
>this for now.
>
>I think that the swap could be used only for anonymous memory, so I
>expected it
>go to zero after the shutdown to the single user mode.
>Does anyone have any ideas?
>Maybe that's something that has already been fixed?
>If not, any ideas on what to look for?
>Thanks!

I've had a hunch of this but haven't gone down this rabbit hole to investigate. Related, yesterday I performed a git gc --aggressive. Top did not report any swap used by git and GB of swap were used. I think to help address this we need a reliable reporting tool. Obviously two separate symptoms, not sure if the same cause.




-- 
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Cheers,
Cy Schubert <Cy.Schubert_at_cschubert.com>
FreeBSD UNIX: <cy_at_FreeBSD.org> Web: http://www.FreeBSD.org

	The need of the many outweighs the greed of the few.