LU-7988 hsm: run HSM coordinator once per second at most

LU-7988 hsm: run HSM coordinator once per second at most

When there is heavy HSM usage, each new HSM request can trigger the
HSM coordinator, which may run many times per seconds. When it is
running it locks the HSM catalog (using cdt_llog_lock) preventing any
other HSM operation to happen, such as insertion, removal or dumping
of the requests.

Limit the coordinator to run once per second, and only if there is
work to do. It will still execute the loop once every 10 seconds (or
as defined by the procfs loop_period parameter) to do housekeeping.

Lustre-change: https://review.whamcloud.com/19341
Lustre-commit: cc6ef11d2f972ebc440013bddda87a536a09750c

Signed-off-by: frank zago <fzago@cray.com>
Change-Id: Ide3f061f8943a3088ea713993521897fb74e5d99
Reviewed-by: Quentin Bouget <quentin.bouget@cea.fr>
Reviewed-by: Faccini Bruno <bruno.faccini@intel.com>
Reviewed-on: https://review.whamcloud.com/28368
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: John L. Hammond <john.hammond@intel.com>