Since the beginning of the year,  we faced with Jenkins 2 master slowdowns : from GC logs, we suspect a memory leak ..

As you can see, the Old Gen memory increased by more than 800 MB in two weeks.

To confirm this memory leak suspicious  : we made a heap dump.

The heap dump shows 51% of the old gen is used to store the attribute Hudson.model.hudson.labels which contains ConcurrentHashMap of 3517 labels used for each jobs launched from the starting of the jvm.

The ConcurrentHashMap containing labels doesn't appear to remove entries after the job has run.

This issue seems to be revealed since the workload on Jenkins has increased a lot in recent months.