So in order to safely call ibv_destroy_cq, I should call ibv_ack_cq_events *after* ibv_poll_cq? The example on the man
page for ibv_get_cq_event calls it before, is it an error?
Flavio
Il 1/2/2012 17:39 PM, Hefty, Sean ha scritto:
If I understood correctly, when ibv_get_cq_event returns, it holds some sort
of lock over the completion queue, which is
ibv_get_cq_event will increment a reference count on the CQ that it is
returning.
released when I call ibv_req_notify_cq. This lock is checked also in
You decrement the count with ibv_ack_cq_events. ibv_req_notify_cq is used to
arm the cq, so that a completion generates an interrupt and a new event.
ibv_destroy_cq, so that:
1) When ibv_destroy_cq returns, I am certain that there is no thread running
somewhere between ibv_get_cq_event and
ibv_req_notify_cq
ibv_destroy_cq will block until all outstanding references on the cq have been
released. The intent is to protect the user from ibv_get_cq_event from
returning a reference to a cq that is being destroyed from another thread,
which could result in a crash in the user's code.
2) When ibv_destroy_cq returns, I am certain that ibv_get_cq_event will not
return the destroyed cq any more.
correct
- Sean
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