Hello,
I have a peer-to-peer like application where on each peer there is
thread listening for connection requests. The peers can at the same time
also actively connect to other peers.
How can the concept or the "rdma_event_channel" now applied to this
scenario?
Until now I only had one "rdma_event_channel" but with the thread, this
leads to a race condition where the thread waits for a
"RDMA_CM_EVENT_CONNECT_REQUST" while the peer tries to actively open a
connection and is awaiting "RDMA_CM_EVENT_ADDR_RESOLVED" etc.
One solution would be to create a new "rdma_event_channel" for each
active connection. But what happens at the accepting side? On the
accepting "rdma_event_channel" (which is now exclusively used for that
purpose), I get a new "rdma_cm_id" for the connection request from the
respective event.
Is it now possible to create again a new "rdma_event_channel" for that
new "rdma_cm_id"? If not, where does the "RDMA_CM_EVENT_ESTABLISHED"
event go to? (The questionable line is marked with "<--HERE???" in the
pseudo code below.)
In pseudo code:
/** connecting part **/
struct rdma_cm_id *id;
struct rdma_event_channel *channel;
struct rdma_cm_event *event;
channel = rdma_create_event_channel();
rdma_create_id(channel, &id, context, RDMA_PS_TCP);
rdma_resolve_addr(id, src_addr, dst_addr, timeout);
rdma_get_cm_event(channel, &event); //expecting ADDR_RESOLVED
rdma_ack_cm_event(event);
//same for rdma_resolve_route() //expecting ROUTE_RESOLVED
rdma_connect(id, conn_param);
rdma_get_event(channel, &event); //expecting ESTABLISHED
rdma_ack_event(event);
... do RDMA here ...
//disconnect
/** accepting thread **/
struct rdma_cm_id *listen_id, *id;
struct rdma_event_channel *listen_channel;
struct rdma_cm_event *listen_event, *event;
channel = rdma_create_event_channel();
rdma_create_id(channel, &id, context, RDMA_PS_TCP);
rdma_bind_addr(id, addr);
rdma_listen(id, backlog);
while(1) {
rdma_get_cm_event(listen_channel, listen_event);
rdma_ack_cm_event(listen_event);
//expecting CONNECT_REQUEST
id = listen_event->id;
id->channel = rdma_create_event_channel(); <-- HERE ???
rdma_accept(id, conn_param);
rdma_get_cm_event(id->channel, event);
//expecting ESTABLISHED
rdma_ack_event(event);
... do RDMA here ...
//await disconnect
}
Many thanks for your advice and kind regards!
Philip
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