I'm trying to test out some changes related to mac_rx_srs_poll_ring()
and bridging, and since I can't currently generate enough traffic
(reliably) to trigger anything special to happen, I'm trying to
understand the mechanism behind polling mode to see if I can 'force'
an interface into that mode briefly for testing.
It seems that mac_rx_srs_poll_ring(), the main polling thread, blocks
waiting on srs_cv. The functions that can signal that cv are:
mac_srs_signal
mac_srs_worker_restart
mac_rx_srs_drain (via MAC_SRS_POLL_RING)
mac_rx_srs_drain_bw (via MAC_SRS_POLL_RING)
various (via MAC_UPDATE_SRS_COUNT_LOCKED)
The first two are used only during quiesce, and the drain functions
are used only when already polling, so that leaves the last one. But
the MAC_UPDATE_SRS_COUNT_LOCKED macro checks for SRS_POLLING first.
The only things that can set that flag are:
mac_rx_srs_drain (via MAC_SRS_POLLING_ON)
mac_rx_srs_drain_bw (via MAC_SRS_POLLING_ON and
MAC_SRS_WORKER_POLLING_ON)
and the trail gets cold right there. So what sets SRS_POLLING in
order to allow MAC_UPDATE_SRS_COUNT_LOCKED to signal the polling
thread? How exactly do we get from interrupt mode to polling mode?
--
James Carlson, Solaris Networking <james.d.carlson at sun.com>
Sun Microsystems / 35 Network Drive 71.232W Vox +1 781 442 2084
MS UBUR02-212 / Burlington MA 01803-2757 42.496N Fax +1 781 442 1677
