This is a specific XFS behaviour. In this case, the slab was using up 4GB of RAM on a 8GB machine, and all of the normal tools were telling us that we were runn

This is a specific XFS behaviour. In this case, the slab was using up 4GB of RAM on a 8GB machine, and all of the normal tools were telling us that we were running out of free space in RAM. No such problems on other file systems.