leaked swap?

[Alan Somers]

On Mon, Mar 18, 2019 at 9:38 AM Andriy Gapon <avg at freebsd.org> wrote:
>
> On 18/03/2019 17:32, Konstantin Belousov wrote:
> > On Mon, Mar 18, 2019 at 05:20:35PM +0200, Andriy Gapon 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?
> > tmpfs, swap-backed (or even memory backed) md, persistent posix shared
> > memory, SysV shared memory.
> >
>
> Thank you.
> There is a single tmpfs mount:
> $ df -t tmpfs -h
> Filesystem    Size    Used   Avail Capacity  Mounted on
> tmpfs         1.0G    4.0K    1.0G     0%    /tmp/tmp
>
> No md devices at all according to mdconfig.
>
> Not sure how to check for the shared memory though.

Try "ipcs -a"