Description of problem:
The Ceph cluster should report a Warning status when the kernel causes excessive swapping due to page cache use. This could be due to customer setting an unusally high osd_memory_target with blue_fs_buffered_io = true for example. The Ceph status should report this as a warning for the customer. This is a supportability/usability enhancement request.

With the plan to default to bluefs_buffered_io = true in 5.0 this warning in the status would be vital.