Huge resident size despite small heap

[Stefan Reich]

Hi, I am currently running OpenJDK 16 on my server (will upgrade to 17 when
I'm sure none of my code is dependent on illegal accesses). OS is Ubuntu 18.

I am noticing that a long running server process eventually (after a few
days) grows enormously in its resident size. Right now it is at 7 GB.
Performing a GC doesn't get it any lower.

The weird part is that the process is run with -Xmx2g, and currently used
heap according to java.lang.Runtime is only 400 MB after GC, going up to at
most 1 GB in operation.

How do these numbers fit together?

I've seen the resident size even higher (13+ GB), and at that point I
noticed the process getting significantly slower too (web pages taking 1-2
seconds to load instead of near instant).

At a typical moment in time, no Java threads are running (I monitor this
every second).

An obvious suspect is of course any native library loaded. The only native
library in use is, I think, the OSHI library.

Any ideas why this might be happening?

Many greetings,
Stefan

-- 
== Gaz.AI ==
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