leaked swap?

[Andriy Gapon]

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.

-- 
Andriy Gapon