...
| Code Block |
|---|
peer = lnet_find_or_create_peer_locked(dst_nid, cpt);
if (!peer->lp_multi-rail && peer_not_local) {
best_gw = lnet_find_route()
if (best_gw) {
/* Don't overwrite the final destination peer */
gw_peer = best_gw->lpn_peer;
}
}
/*
* at this point we can be keeping track of two peers
* 1. The peer for the gateway router (gw_peer)
* 2. The peer for the final destination (peer)
*/
/* Let's deal with the case where the final destination is Non-MR */
if (!peer->lp_multi_rail) {
/*
* if the final destination peer is non-MR then
* check if we have a preferred local NI associated with the final destination peer
* if yes then my best_ni will be the preferred NI of the peer.
* if I don't have a best_ni then I'll need to pick one, and stick with it going forward
* to pick one we need to look at the gw_peer.
* if the gw_peer is MR then in order to know that we must've looked up a best_gw
* set the preferred local NI for the final destination peer based on the net_id of that best_gw NID.
* NOTE: Currently we do not support having different gateways reach the same final destination network.
* IE: tcp1 <gw1>@tcp
* tcp1 <gw2>@tcp2
* That's not supported at this point, although there is a ticket opened for it.
* Either way, we'll need to stick with only one preferred NI, so we just pick the first one we come up with.
* Use the preferred NI to send the message to the non-MR peer
* goto the pick_peer tag to select one of the router's NIs.
*
* if the gw_peer is Non-MR then it only has one peer NI, so we use that to select the local NI based on the net_id of the gateway's NID.
* Store that preferred NI in the peer.
* Use the preferred NI to send the message to the non-MR peer via the single peer NI of the gateway.
*/
} |
Potential implementation in psudo code
In master
The idea behind the code is to select the local ni we're going to send from based on the gw_peer, but store that NI as the preferred NI for the non-MR non-local peer.
When we deal with the non-MR non-local peer we're always going to use the same interface to send from and not confuse it.
Afterwards we can just deal with the gw directly, whether it's MR or non-MR, then we can just iterate through its interfaces as we normally would
| Code Block |
|---|
if (msg->msg_type == LNET_MSG_REPLY ||
msg->msg_type == LNET_MSG_ACK ||
!lnet_peer_is_multi_rail(peer) ||
best_ni) {
...
if (best_lpni && !lnet_get_net_locked(LNET_NIDNET(dst_nid))) {
...
gw_peer = best_gw->lpni_peer_net->lpn_peer;
/* use the gw_peer to deal with the router for now */
...
}
...
if (!lnet_peer_is_multi_rail(peer)) {
__u32 net_id;
/* if gw_peer is not NULL, then we must have a best_gw */
if (gw_peer) (
net_id = LNET_NIDNET(best_gw->lpni_nid);
else
net_id = LNET_NIDNET(best_lpni->lpni_nid);
...
if (!best_ni) {
...
if (final_dst_lpni->lpni_pref_nnids == 1) {
best_ni = lnet_nid2ni_locked(final_dst_lpni->lpni_pref.nid, cpt);
} else
peer_net = lnet_peer_get_net_locked((gw_peer) ? gw_peer : peer, net);
...
}
if (!best_ni) {
/* if we're routing then we want to look at the gw */
struct lnet_lpni lpni_use = (gw_peer) ? best_gw : best_lpni;
best_ni = lnet_net2ni_locked(net_id, cpt);
/* update the code to use lpni_use instead of best_lpni */
...
/* now we need to pick the lpni for which we will update it's preferred local_ni */
if (!gw_peer)
/* continue doing what the code does now */
}
/* Set preferred NI if necessary. */
if (gw_peer)
if (final_dst_lpni->lpni_pref_nnids == 0)
/* set preferred ni */
else
if (lpni->lpni_pref_nnids == 0)
/* set preferred ni */
}
/* deal with the gw directly */
if (gw_peer)
peer = gw_peer
} |