freebsd stable - Jun 2020 - swap space issues

On Wednesday, 24 June 2020 at  9:36:23 -0700, Donald Wilde
wrote:
> All,
>
> I recently upgraded my 12-STABLE system to the latest, and now my
> swap subsystems aren't working. I deliberately set up a 40GB
> partition for swap, and when I do 'top -t' I am only seeing 7906M
> total.
That looks suspiciously like the difference from 32 GB.  Could it be
numeric overflow?  And if so, where?  What does pstat -s say?
> When using synth, it shows swap usage of < 2%, but then it gives the
> 'out of swap' complaint and tosses all my users out into neverland.
Unless this also causes kernel messages to that effect, this, too,
could be an issue with synth.

Greg
--
Sent from my desktop computer.
Finger grog at FreeBSD.org for PGP public key.
See complete headers for address and phone numbers.
This message is digitally signed.  If your Microsoft mail program
reports problems, please read http://lemis.com/broken-MUA
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 163 bytes
Desc: not available
URL:
<http://lists.freebsd.org/pipermail/freebsd-stable/attachments/20200625/8d7c71c6/attachment.sig>

On 6/24/20, Greg 'groggy' Lehey <grog at freebsd.org>
wrote:
> On Wednesday, 24 June 2020 at  9:36:23 -0700, Donald Wilde wrote:
>> All,
>>
>> I recently upgraded my 12-STABLE system to the latest, and now my
>> swap subsystems aren't working. I deliberately set up a 40GB
>> partition for swap, and when I do 'top -t' I am only seeing
7906M
>> total.
>
> That looks suspiciously like the difference from 32 GB.  Could it be
> numeric overflow?  And if so, where?  What does pstat -s say?
>
Well, hi Greg! LTNT2!

pstat -shm:

/dev/ada0s1b  65536 (1M blocks), Used: 1.5G, Avail: 63G, Capacity: 2%

This is while synth is still running on openblas and openjdk8.
>> When using synth, it shows swap usage of < 2%, but then it gives the
>> 'out of swap' complaint and tosses all my users out into
neverland.
>
> Unless this also causes kernel messages to that effect, this, too,
> could be an issue with synth.
I believe the messages about 'out of swap' were from the kernel as it
died, not synth. As I say, it killed all my active users, both root
and non-root.

Why does _top_ show the 7906M number? I suspect that it's deeper than
just synth.

What else can I share to help diagnose this?
>
> Greg
> --
> Sent from my desktop computer.
[snip]
-- 
Don Wilde
****************************************************
* What is the Internet of Things but a system *
* of systems including humans?                     *
****************************************************