Significant memory leak in 9.3p10?

Konstantin Belousov kostikbel at
Fri Mar 27 09:16:44 UTC 2015

On Thu, Mar 26, 2015 at 03:46:05PM -0400, J David wrote:
> On Mon, Mar 16, 2015 at 7:52 PM, J David <j.david.lists at> wrote:
> > On Mon, Mar 16, 2015 at 7:24 PM, Konstantin Belousov
> > <kostikbel at> wrote:
> >> There are a lot of possibilities to create persistent anonymous shared
> >> memory objects.  Not complete list is tmpfs mounts, swap-backed md disks,
> >> sysv shared memory, possibly posix shared memory (I do not remember which
> >> implementation is used in stable/9).
> >
> > If that's the explanation, how could it be
> > detected/measured/investigated/resolved/prevented?
> >
> > Under ordinary circumstances, machines will go run like this for days/weeks:
> >
> > Mem: 549M Active, 3623M Inact, 567M Wired, 3484K Cache, 827M Buf, 3156M Free
> > Swap: 1024M Total, 1024M Free
> >
> > Then, when this happens, it rapidly degrades from that to so bad that
> > processes start getting killed for being out of swap space.
> These FreeBSD machines running out of swap space and dying continues
> to be a daily problem causing outages and unscheduled reboots.  Is
> there really no way to even research what might be causing the
> problem?
> (Widening the cross-posting in the hopes of eliciting more help, so
> the brief summary of the problem orginally posted to freebsd-stable is
> that an unknown actor consumes all the user-space memory in the
> system, including swap space, to the point where processes are killed
> for being out of swap space, but if every process on the machine is
> stopped, very little of the user-space memory in use is freed.
> Original message with more details is here:
> .)
> There are no tmpfs mounts or md disks, so it would have to be one of
> the other causes.  How can FreeBSD's use of persistent, anonymous
> shared memory objects be investigated, measured, or controlled so we
> can get a handle on this issue?

Start by providing useful information about your system, not a description
of the information.

E.g., a consistent snapshot of the following:
ps auxww
mount -v
mdconfig -lv
vmstat -z
vmstat -m
vmstat -s
sysctl -a
ipcs -a

Collect this data both during the normal run, run while the problem appear
but userspace is not killed, and after you killed the processes.

Just in case, show kldstat.

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