Change the way we increase poll group reference counts
for round-robin scheduling.
So far we used to increase them whenever someone called
vhost_get_poll_group() and this worked fine for Vhost-Block
which picks a new poll group for each session. Vhost-SCSI,
however, picks only one poll group for all sessions on
a vhost device. This means that some threads will have
multiple Vhost-SCSI pollers but will still appear to the
vhost scheduler as if they had only one.
To fix it, increase poll group refcnt only when sessions
are really being started - in vhost_session_start_done().
Change-Id: I60f0d2101239e5a91138a5afd30c51dc1ccf7c2e
Signed-off-by: Darek Stojaczyk <dariusz.stojaczyk@intel.com>
Reviewed-on: https://review.gerrithub.io/c/spdk/spdk/+/466733
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
Reviewed-by: Vitaliy Mysak <vitaliy.mysak@intel.com>
Reviewed-by: Jim Harris <james.r.harris@intel.com>
Reviewed-by: Changpeng Liu <changpeng.liu@intel.com>
6e77b0b68d