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LU-14649 lnet: Correct distance calculation of local NIDs
[fs/lustre-release.git] / lnet / lnet / lib-move.c
index 8ef55e7..e458bbf 100644 (file)
@@ -27,7 +27,6 @@
  */
 /*
  * This file is part of Lustre, http://www.lustre.org/
- * Lustre is a trademark of Sun Microsystems, Inc.
  *
  * lnet/lnet/lib-move.c
  *
@@ -69,6 +68,30 @@ lnet_msg_is_response(struct lnet_msg *msg)
        return msg->msg_type == LNET_MSG_ACK || msg->msg_type == LNET_MSG_REPLY;
 }
 
+static inline bool
+lnet_response_tracking_enabled(__u32 msg_type, unsigned int md_options)
+{
+       if (md_options & LNET_MD_NO_TRACK_RESPONSE)
+               /* Explicitly disabled in MD options */
+               return false;
+
+       if (md_options & LNET_MD_TRACK_RESPONSE)
+               /* Explicity enabled in MD options */
+               return true;
+
+       if (lnet_response_tracking == 3)
+               /* Enabled for all message types */
+               return true;
+
+       if (msg_type == LNET_MSG_PUT)
+               return lnet_response_tracking == 2;
+
+       if (msg_type == LNET_MSG_GET)
+               return lnet_response_tracking == 1;
+
+       return false;
+}
+
 static inline struct lnet_comm_count *
 get_stats_counts(struct lnet_element_stats *stats,
                 enum lnet_stats_type stats_type)
@@ -702,7 +725,7 @@ lnet_prep_send(struct lnet_msg *msg, int type, struct lnet_process_id target,
        msg->msg_hdr.payload_length = cpu_to_le32(len);
 }
 
-static void
+void
 lnet_ni_send(struct lnet_ni *ni, struct lnet_msg *msg)
 {
        void *priv = msg->msg_private;
@@ -816,8 +839,10 @@ lnet_post_send_locked(struct lnet_msg *msg, int do_send)
        LASSERT(!do_send || msg->msg_tx_delayed);
        LASSERT(!msg->msg_receiving);
        LASSERT(msg->msg_tx_committed);
+
        /* can't get here if we're sending to the loopback interface */
-       LASSERT(lp->lpni_nid != the_lnet.ln_loni->ni_nid);
+       if (the_lnet.ln_loni)
+               LASSERT(lp->lpni_nid != the_lnet.ln_loni->ni_nid);
 
        /* NB 'lp' is always the next hop */
        if ((msg->msg_target.pid & LNET_PID_USERFLAG) == 0 &&
@@ -902,6 +927,12 @@ lnet_post_send_locked(struct lnet_msg *msg, int do_send)
                }
        }
 
+       if (unlikely(!list_empty(&the_lnet.ln_delay_rules)) &&
+           lnet_delay_rule_match_locked(&msg->msg_hdr, msg)) {
+               msg->msg_tx_delayed = 1;
+               return LNET_CREDIT_WAIT;
+       }
+
        /* unset the tx_delay flag as we're going to send it now */
        msg->msg_tx_delayed = 0;
 
@@ -1259,24 +1290,6 @@ routing_off:
        }
 }
 
-static int
-lnet_compare_gw_lpnis(struct lnet_peer_ni *p1, struct lnet_peer_ni *p2)
-{
-       if (p1->lpni_txqnob < p2->lpni_txqnob)
-               return 1;
-
-       if (p1->lpni_txqnob > p2->lpni_txqnob)
-               return -1;
-
-       if (p1->lpni_txcredits > p2->lpni_txcredits)
-               return 1;
-
-       if (p1->lpni_txcredits < p2->lpni_txcredits)
-               return -1;
-
-       return 0;
-}
-
 static struct lnet_peer_ni *
 lnet_select_peer_ni(struct lnet_ni *best_ni, lnet_nid_t dst_nid,
                    struct lnet_peer *peer,
@@ -1296,9 +1309,11 @@ lnet_select_peer_ni(struct lnet_ni *best_ni, lnet_nid_t dst_nid,
                INT_MIN;
        int best_lpni_healthv = (best_lpni) ?
                atomic_read(&best_lpni->lpni_healthv) : 0;
-       bool preferred = false;
-       bool ni_is_pref;
+       bool best_lpni_is_preferred = false;
+       bool lpni_is_preferred;
        int lpni_healthv;
+       __u32 lpni_sel_prio;
+       __u32 best_sel_prio = LNET_MAX_SELECTION_PRIORITY;
 
        while ((lpni = lnet_get_next_peer_ni_locked(peer, peer_net, lpni))) {
                /*
@@ -1306,56 +1321,76 @@ lnet_select_peer_ni(struct lnet_ni *best_ni, lnet_nid_t dst_nid,
                 * preferred, then let's use it
                 */
                if (best_ni) {
-                       ni_is_pref = lnet_peer_is_pref_nid_locked(lpni,
+                       lpni_is_preferred = lnet_peer_is_pref_nid_locked(lpni,
                                                                best_ni->ni_nid);
-                       CDEBUG(D_NET, "%s ni_is_pref = %d\n",
-                              libcfs_nid2str(best_ni->ni_nid), ni_is_pref);
+                       CDEBUG(D_NET, "%s lpni_is_preferred = %d\n",
+                              libcfs_nid2str(best_ni->ni_nid),
+                              lpni_is_preferred);
                } else {
-                       ni_is_pref = false;
+                       lpni_is_preferred = false;
                }
 
                lpni_healthv = atomic_read(&lpni->lpni_healthv);
+               lpni_sel_prio = lpni->lpni_sel_priority;
 
                if (best_lpni)
-                       CDEBUG(D_NET, "%s c:[%d, %d], s:[%d, %d]\n",
+                       CDEBUG(D_NET, "n:[%s, %s] h:[%d, %d] p:[%d, %d] c:[%d, %d] s:[%d, %d]\n",
                                libcfs_nid2str(lpni->lpni_nid),
+                               libcfs_nid2str(best_lpni->lpni_nid),
+                               lpni_healthv, best_lpni_healthv,
+                               lpni_sel_prio, best_sel_prio,
                                lpni->lpni_txcredits, best_lpni_credits,
                                lpni->lpni_seq, best_lpni->lpni_seq);
+               else
+                       goto select_lpni;
 
                /* pick the healthiest peer ni */
-               if (lpni_healthv < best_lpni_healthv) {
+               if (lpni_healthv < best_lpni_healthv)
                        continue;
-               } else if (lpni_healthv > best_lpni_healthv) {
-                       best_lpni_healthv = lpni_healthv;
+               else if (lpni_healthv > best_lpni_healthv) {
+                       if (best_lpni_is_preferred)
+                               best_lpni_is_preferred = false;
+                       goto select_lpni;
+               }
+
+               if (lpni_sel_prio > best_sel_prio)
+                       continue;
+               else if (lpni_sel_prio < best_sel_prio) {
+                       if (best_lpni_is_preferred)
+                               best_lpni_is_preferred = false;
+                       goto select_lpni;
+               }
+
                /* if this is a preferred peer use it */
-               } else if (!preferred && ni_is_pref) {
-                       preferred = true;
-               } else if (preferred && !ni_is_pref) {
-                       /*
-                        * this is not the preferred peer so let's ignore
+               if (!best_lpni_is_preferred && lpni_is_preferred) {
+                       best_lpni_is_preferred = true;
+                       goto select_lpni;
+               } else if (best_lpni_is_preferred && !lpni_is_preferred) {
+                       /* this is not the preferred peer so let's ignore
                         * it.
                         */
                        continue;
-               } else if (lpni->lpni_txcredits < best_lpni_credits) {
-                       /*
-                        * We already have a peer that has more credits
+               }
+
+               if (lpni->lpni_txcredits < best_lpni_credits)
+                       /* We already have a peer that has more credits
                         * available than this one. No need to consider
                         * this peer further.
                         */
                        continue;
-               } else if (lpni->lpni_txcredits == best_lpni_credits) {
-                       /*
-                        * The best peer found so far and the current peer
-                        * have the same number of available credits let's
-                        * make sure to select between them using Round
-                        * Robin
-                        */
-                       if (best_lpni) {
-                               if (best_lpni->lpni_seq <= lpni->lpni_seq)
-                                       continue;
-                       }
-               }
+               else if (lpni->lpni_txcredits > best_lpni_credits)
+                       goto select_lpni;
 
+               /* The best peer found so far and the current peer
+                * have the same number of available credits let's
+                * make sure to select between them using Round Robin
+                */
+               if (best_lpni && (best_lpni->lpni_seq <= lpni->lpni_seq))
+                       continue;
+select_lpni:
+               best_lpni_is_preferred = lpni_is_preferred;
+               best_lpni_healthv = lpni_healthv;
+               best_sel_prio = lpni_sel_prio;
                best_lpni = lpni;
                best_lpni_credits = lpni->lpni_txcredits;
        }
@@ -1390,10 +1425,9 @@ lnet_find_best_lpni(struct lnet_ni *lni, lnet_nid_t dst_nid,
                    struct lnet_peer *peer, __u32 net_id)
 {
        struct lnet_peer_net *peer_net;
-       __u32 any_net = LNET_NIDNET(LNET_NID_ANY);
 
        /* find the best_lpni on any local network */
-       if (net_id == any_net) {
+       if (net_id == LNET_NET_ANY) {
                struct lnet_peer_ni *best_lpni = NULL;
                struct lnet_peer_net *lpn;
                list_for_each_entry(lpn, &peer->lp_peer_nets, lpn_peer_nets) {
@@ -1414,6 +1448,24 @@ lnet_find_best_lpni(struct lnet_ni *lni, lnet_nid_t dst_nid,
        return NULL;
 }
 
+static int
+lnet_compare_gw_lpnis(struct lnet_peer_ni *lpni1, struct lnet_peer_ni *lpni2)
+{
+       if (lpni1->lpni_txqnob < lpni2->lpni_txqnob)
+               return 1;
+
+       if (lpni1->lpni_txqnob > lpni2->lpni_txqnob)
+               return -1;
+
+       if (lpni1->lpni_txcredits > lpni2->lpni_txcredits)
+               return 1;
+
+       if (lpni1->lpni_txcredits < lpni2->lpni_txcredits)
+               return -1;
+
+       return 0;
+}
+
 /* Compare route priorities and hop counts */
 static int
 lnet_compare_routes(struct lnet_route *r1, struct lnet_route *r2)
@@ -1438,6 +1490,7 @@ lnet_compare_routes(struct lnet_route *r1, struct lnet_route *r2)
 
 static struct lnet_route *
 lnet_find_route_locked(struct lnet_remotenet *rnet, __u32 src_net,
+                      struct lnet_peer_ni *remote_lpni,
                       struct lnet_route **prev_route,
                       struct lnet_peer_ni **gwni)
 {
@@ -1446,6 +1499,8 @@ lnet_find_route_locked(struct lnet_remotenet *rnet, __u32 src_net,
        struct lnet_route *last_route;
        struct lnet_route *route;
        int rc;
+       bool best_rte_is_preferred = false;
+       lnet_nid_t gw_pnid;
 
        CDEBUG(D_NET, "Looking up a route to %s, from %s\n",
               libcfs_net2str(rnet->lrn_net), libcfs_net2str(src_net));
@@ -1454,43 +1509,75 @@ lnet_find_route_locked(struct lnet_remotenet *rnet, __u32 src_net,
        list_for_each_entry(route, &rnet->lrn_routes, lr_list) {
                if (!lnet_is_route_alive(route))
                        continue;
+               gw_pnid = route->lr_gateway->lp_primary_nid;
 
-               /*
-                * Restrict the selection of the router NI on the src_net
-                * provided. If the src_net is LNET_NID_ANY, then select
-                * the best interface available.
+               /* no protection on below fields, but it's harmless */
+               if (last_route && (last_route->lr_seq - route->lr_seq < 0))
+                       last_route = route;
+
+               /* if the best route found is in the preferred list then
+                * tag it as preferred and use it later on. But if we
+                * didn't find any routes which are on the preferred list
+                * then just use the best route possible.
                 */
-               if (!best_route) {
+               rc = lnet_peer_is_pref_rtr_locked(remote_lpni, gw_pnid);
+
+               if (!best_route || (rc && !best_rte_is_preferred)) {
+                       /* Restrict the selection of the router NI on the
+                        * src_net provided. If the src_net is LNET_NID_ANY,
+                        * then select the best interface available.
+                        */
                        lpni = lnet_find_best_lpni(NULL, LNET_NID_ANY,
                                                   route->lr_gateway,
                                                   src_net);
-                       if (lpni) {
-                               best_route = last_route = route;
-                               best_gw_ni = lpni;
-                       } else {
-                               CDEBUG(D_NET, "Gateway %s does not have a peer NI on net %s\n",
-                                      libcfs_nid2str(route->lr_gateway->lp_primary_nid),
+                       if (!lpni) {
+                               CDEBUG(D_NET,
+                                      "Gateway %s does not have a peer NI on net %s\n",
+                                      libcfs_nid2str(gw_pnid),
                                       libcfs_net2str(src_net));
+                               continue;
                        }
+               }
 
+               if (rc && !best_rte_is_preferred) {
+                       /* This is the first preferred route we found,
+                        * so it beats any route found previously
+                        */
+                       best_route = route;
+                       if (!last_route)
+                               last_route = route;
+                       best_gw_ni = lpni;
+                       best_rte_is_preferred = true;
+                       CDEBUG(D_NET, "preferred gw = %s\n",
+                              libcfs_nid2str(gw_pnid));
+                       continue;
+               } else if ((!rc) && best_rte_is_preferred)
+                       /* The best route we found so far is in the preferred
+                        * list, so it beats any non-preferred route
+                        */
                        continue;
-               }
 
-               /* no protection on below fields, but it's harmless */
-               if (last_route->lr_seq - route->lr_seq < 0)
-                       last_route = route;
+               if (!best_route) {
+                       best_route = last_route = route;
+                       best_gw_ni = lpni;
+                       continue;
+               }
 
                rc = lnet_compare_routes(route, best_route);
                if (rc == -1)
                        continue;
 
+               /* Restrict the selection of the router NI on the
+                * src_net provided. If the src_net is LNET_NID_ANY,
+                * then select the best interface available.
+                */
                lpni = lnet_find_best_lpni(NULL, LNET_NID_ANY,
                                           route->lr_gateway,
                                           src_net);
-               /* restrict the lpni on the src_net if specified */
                if (!lpni) {
-                       CDEBUG(D_NET, "Gateway %s does not have a peer NI on net %s\n",
-                              libcfs_nid2str(route->lr_gateway->lp_primary_nid),
+                       CDEBUG(D_NET,
+                              "Gateway %s does not have a peer NI on net %s\n",
+                              libcfs_nid2str(gw_pnid),
                               libcfs_net2str(src_net));
                        continue;
                }
@@ -1527,6 +1614,7 @@ lnet_get_best_ni(struct lnet_net *local_net, struct lnet_ni *best_ni,
        unsigned int shortest_distance;
        int best_credits;
        int best_healthv;
+       __u32 best_sel_prio;
 
        /*
         * If there is no peer_ni that we can send to on this network,
@@ -1536,6 +1624,7 @@ lnet_get_best_ni(struct lnet_net *local_net, struct lnet_ni *best_ni,
                return best_ni;
 
        if (best_ni == NULL) {
+               best_sel_prio = LNET_MAX_SELECTION_PRIORITY;
                shortest_distance = UINT_MAX;
                best_credits = INT_MIN;
                best_healthv = 0;
@@ -1544,6 +1633,7 @@ lnet_get_best_ni(struct lnet_net *local_net, struct lnet_ni *best_ni,
                                                     best_ni->ni_dev_cpt);
                best_credits = atomic_read(&best_ni->ni_tx_credits);
                best_healthv = atomic_read(&best_ni->ni_healthv);
+               best_sel_prio = best_ni->ni_sel_priority;
        }
 
        while ((ni = lnet_get_next_ni_locked(local_net, ni))) {
@@ -1551,10 +1641,12 @@ lnet_get_best_ni(struct lnet_net *local_net, struct lnet_ni *best_ni,
                int ni_credits;
                int ni_healthv;
                int ni_fatal;
+               __u32 ni_sel_prio;
 
                ni_credits = atomic_read(&ni->ni_tx_credits);
                ni_healthv = atomic_read(&ni->ni_healthv);
                ni_fatal = atomic_read(&ni->ni_fatal_error_on);
+               ni_sel_prio = ni->ni_sel_priority;
 
                /*
                 * calculate the distance from the CPT on which
@@ -1565,12 +1657,6 @@ lnet_get_best_ni(struct lnet_net *local_net, struct lnet_ni *best_ni,
                                            md_cpt,
                                            ni->ni_dev_cpt);
 
-               CDEBUG(D_NET, "compare ni %s [c:%d, d:%d, s:%d] with best_ni %s [c:%d, d:%d, s:%d]\n",
-                      libcfs_nid2str(ni->ni_nid), ni_credits, distance,
-                      ni->ni_seq, (best_ni) ? libcfs_nid2str(best_ni->ni_nid)
-                       : "not seleced", best_credits, shortest_distance,
-                       (best_ni) ? best_ni->ni_seq : 0);
-
                /*
                 * All distances smaller than the NUMA range
                 * are treated equally.
@@ -1582,31 +1668,47 @@ lnet_get_best_ni(struct lnet_net *local_net, struct lnet_ni *best_ni,
                 * Select on health, shorter distance, available
                 * credits, then round-robin.
                 */
-               if (ni_fatal) {
+               if (ni_fatal)
                        continue;
-               } else if (ni_healthv < best_healthv) {
+
+               if (best_ni)
+                       CDEBUG(D_NET, "compare ni %s [c:%d, d:%d, s:%d, p:%u] with best_ni %s [c:%d, d:%d, s:%d, p:%u]\n",
+                              libcfs_nid2str(ni->ni_nid), ni_credits, distance,
+                              ni->ni_seq, ni_sel_prio,
+                              (best_ni) ? libcfs_nid2str(best_ni->ni_nid)
+                              : "not selected", best_credits, shortest_distance,
+                              (best_ni) ? best_ni->ni_seq : 0,
+                              best_sel_prio);
+               else
+                       goto select_ni;
+
+               if (ni_healthv < best_healthv)
                        continue;
-               } else if (ni_healthv > best_healthv) {
-                       best_healthv = ni_healthv;
-                       /*
-                        * If we're going to prefer this ni because it's
-                        * the healthiest, then we should set the
-                        * shortest_distance in the algorithm in case
-                        * there are multiple NIs with the same health but
-                        * different distances.
-                        */
-                       if (distance < shortest_distance)
-                               shortest_distance = distance;
-               } else if (distance > shortest_distance) {
+               else if (ni_healthv > best_healthv)
+                       goto select_ni;
+
+               if (ni_sel_prio > best_sel_prio)
                        continue;
-               } else if (distance < shortest_distance) {
-                       shortest_distance = distance;
-               } else if (ni_credits < best_credits) {
+               else if (ni_sel_prio < best_sel_prio)
+                       goto select_ni;
+
+               if (distance > shortest_distance)
                        continue;
-               } else if (ni_credits == best_credits) {
-                       if (best_ni && best_ni->ni_seq <= ni->ni_seq)
-                               continue;
-               }
+               else if (distance < shortest_distance)
+                       goto select_ni;
+
+               if (ni_credits < best_credits)
+                       continue;
+               else if (ni_credits > best_credits)
+                       goto select_ni;
+
+               if (best_ni && best_ni->ni_seq <= ni->ni_seq)
+                       continue;
+
+select_ni:
+               best_sel_prio = ni_sel_prio;
+               shortest_distance = distance;
+               best_healthv = ni_healthv;
                best_ni = ni;
                best_credits = ni_credits;
        }
@@ -1666,6 +1768,9 @@ lnet_handle_lo_send(struct lnet_send_data *sd)
        struct lnet_msg *msg = sd->sd_msg;
        int cpt = sd->sd_cpt;
 
+       if (the_lnet.ln_state != LNET_STATE_RUNNING)
+               return -ESHUTDOWN;
+
        /* No send credit hassles with LOLND */
        lnet_ni_addref_locked(the_lnet.ln_loni, cpt);
        msg->msg_hdr.dest_nid = cpu_to_le64(the_lnet.ln_loni->ni_nid);
@@ -1692,11 +1797,24 @@ lnet_handle_send(struct lnet_send_data *sd)
        __u32 routing = send_case & REMOTE_DST;
         struct lnet_rsp_tracker *rspt;
 
-       /*
-        * Increment sequence number of the selected peer so that we
-        * pick the next one in Round Robin.
+       /* Increment sequence number of the selected peer, peer net,
+        * local ni and local net so that we pick the next ones
+        * in Round Robin.
         */
        best_lpni->lpni_seq++;
+       best_lpni->lpni_peer_net->lpn_seq++;
+       best_ni->ni_seq++;
+       best_ni->ni_net->net_seq++;
+
+       CDEBUG(D_NET, "%s NI seq info: [%d:%d:%d:%u] %s LPNI seq info [%d:%d:%d:%u]\n",
+              libcfs_nid2str(best_ni->ni_nid),
+              best_ni->ni_seq, best_ni->ni_net->net_seq,
+              atomic_read(&best_ni->ni_tx_credits),
+              best_ni->ni_sel_priority,
+              libcfs_nid2str(best_lpni->lpni_nid),
+              best_lpni->lpni_seq, best_lpni->lpni_peer_net->lpn_seq,
+              best_lpni->lpni_txcredits,
+              best_lpni->lpni_sel_priority);
 
        /*
         * grab a reference on the peer_ni so it sticks around even if
@@ -1890,8 +2008,7 @@ struct lnet_ni *
 lnet_find_best_ni_on_spec_net(struct lnet_ni *cur_best_ni,
                              struct lnet_peer *peer,
                              struct lnet_peer_net *peer_net,
-                             int cpt,
-                             bool incr_seq)
+                             int cpt)
 {
        struct lnet_net *local_net;
        struct lnet_ni *best_ni;
@@ -1911,9 +2028,6 @@ lnet_find_best_ni_on_spec_net(struct lnet_ni *cur_best_ni,
        best_ni = lnet_get_best_ni(local_net, cur_best_ni,
                                   peer, peer_net, cpt);
 
-       if (incr_seq && best_ni)
-               best_ni->ni_seq++;
-
        return best_ni;
 }
 
@@ -1922,6 +2036,7 @@ lnet_initiate_peer_discovery(struct lnet_peer_ni *lpni, struct lnet_msg *msg,
                             int cpt)
 {
        struct lnet_peer *peer;
+       struct lnet_peer_ni *new_lpni;
        int rc;
 
        lnet_peer_ni_addref_locked(lpni);
@@ -1943,21 +2058,38 @@ lnet_initiate_peer_discovery(struct lnet_peer_ni *lpni, struct lnet_msg *msg,
                lnet_peer_ni_decref_locked(lpni);
                return rc;
        }
-       /* The peer may have changed. */
-       peer = lpni->lpni_peer_net->lpn_peer;
+
+       new_lpni = lnet_find_peer_ni_locked(lpni->lpni_nid);
+       if (!new_lpni) {
+               lnet_peer_ni_decref_locked(lpni);
+               return -ENOENT;
+       }
+
+       peer = new_lpni->lpni_peer_net->lpn_peer;
        spin_lock(&peer->lp_lock);
-       if (lnet_peer_is_uptodate_locked(peer)) {
+       if (lpni == new_lpni && lnet_peer_is_uptodate_locked(peer)) {
+               /* The peer NI did not change and the peer is up to date.
+                * Nothing more to do.
+                */
                spin_unlock(&peer->lp_lock);
                lnet_peer_ni_decref_locked(lpni);
+               lnet_peer_ni_decref_locked(new_lpni);
                return 0;
        }
-       /* queue message and return */
+       spin_unlock(&peer->lp_lock);
+
+       /* Either the peer NI changed during discovery, or the peer isn't up
+        * to date. In both cases we want to queue the message on the
+        * (possibly new) peer's pending queue and queue the peer for discovery
+        */
        msg->msg_sending = 0;
        msg->msg_txpeer = NULL;
-       list_add_tail(&msg->msg_list, &peer->lp_dc_pendq);
-       spin_unlock(&peer->lp_lock);
+       lnet_net_unlock(cpt);
+       lnet_peer_queue_message(peer, msg);
+       lnet_net_lock(cpt);
 
        lnet_peer_ni_decref_locked(lpni);
+       lnet_peer_ni_decref_locked(new_lpni);
 
        CDEBUG(D_NET, "msg %p delayed. %s pending discovery\n",
               msg, libcfs_nid2str(peer->lp_primary_nid));
@@ -1972,7 +2104,6 @@ lnet_handle_find_routed_path(struct lnet_send_data *sd,
                             struct lnet_peer **gw_peer)
 {
        int rc;
-       __u32 local_lnet;
        struct lnet_peer *gw;
        struct lnet_peer *lp;
        struct lnet_peer_net *lpn;
@@ -1986,6 +2117,8 @@ lnet_handle_find_routed_path(struct lnet_send_data *sd,
        lnet_nid_t src_nid = (sd->sd_src_nid != LNET_NID_ANY) ? sd->sd_src_nid :
                (sd->sd_best_ni != NULL) ? sd->sd_best_ni->ni_nid :
                LNET_NID_ANY;
+       int best_lpn_healthv = 0;
+       __u32 best_lpn_sel_prio = LNET_MAX_SELECTION_PRIORITY;
 
        CDEBUG(D_NET, "using src nid %s for route restriction\n",
               libcfs_nid2str(src_nid));
@@ -1999,10 +2132,8 @@ lnet_handle_find_routed_path(struct lnet_send_data *sd,
                if (gwni) {
                        gw = gwni->lpni_peer_net->lpn_peer;
                        lnet_peer_ni_decref_locked(gwni);
-                       if (gw->lp_rtr_refcount) {
-                               local_lnet = LNET_NIDNET(sd->sd_rtr_nid);
+                       if (gw->lp_rtr_refcount)
                                route_found = true;
-                       }
                } else {
                        CWARN("No peer NI for gateway %s. Attempting to find an alternative route.\n",
                               libcfs_nid2str(sd->sd_rtr_nid));
@@ -2010,63 +2141,96 @@ lnet_handle_find_routed_path(struct lnet_send_data *sd,
        }
 
        if (!route_found) {
-               /* we've already looked up the initial lpni using dst_nid */
-               lpni = sd->sd_best_lpni;
-               /* the peer tree must be in existence */
-               LASSERT(lpni && lpni->lpni_peer_net &&
-                       lpni->lpni_peer_net->lpn_peer);
-               lp = lpni->lpni_peer_net->lpn_peer;
-
-               list_for_each_entry(lpn, &lp->lp_peer_nets, lpn_peer_nets) {
-                       /* is this remote network reachable?  */
-                       rnet = lnet_find_rnet_locked(lpn->lpn_net_id);
-                       if (!rnet)
-                               continue;
+               if (sd->sd_msg->msg_routing) {
+                       /* If I'm routing this message then I need to find the
+                        * next hop based on the destination NID
+                        */
+                       best_rnet = lnet_find_rnet_locked(LNET_NIDNET(sd->sd_dst_nid));
+                       if (!best_rnet) {
+                               CERROR("Unable to route message to %s - Route table may be misconfigured\n",
+                                      libcfs_nid2str(sd->sd_dst_nid));
+                               return -EHOSTUNREACH;
+                       }
+               } else {
+                       /* we've already looked up the initial lpni using
+                        * dst_nid
+                        */
+                       lpni = sd->sd_best_lpni;
+                       /* the peer tree must be in existence */
+                       LASSERT(lpni && lpni->lpni_peer_net &&
+                               lpni->lpni_peer_net->lpn_peer);
+                       lp = lpni->lpni_peer_net->lpn_peer;
+
+                       list_for_each_entry(lpn, &lp->lp_peer_nets, lpn_peer_nets) {
+                               /* is this remote network reachable?  */
+                               rnet = lnet_find_rnet_locked(lpn->lpn_net_id);
+                               if (!rnet)
+                                       continue;
 
-                       if (!best_lpn) {
+                               if (!best_lpn) {
+                                       best_lpn = lpn;
+                                       best_rnet = rnet;
+                               }
+
+                               /* select the preferred peer net */
+                               if (best_lpn_healthv > lpn->lpn_healthv)
+                                       continue;
+                               else if (best_lpn_healthv < lpn->lpn_healthv)
+                                       goto use_lpn;
+
+                               if (best_lpn_sel_prio < lpn->lpn_sel_priority)
+                                       continue;
+                               else if (best_lpn_sel_prio > lpn->lpn_sel_priority)
+                                       goto use_lpn;
+
+                               if (best_lpn->lpn_seq <= lpn->lpn_seq)
+                                       continue;
+use_lpn:
+                               best_lpn_healthv = lpn->lpn_healthv;
+                               best_lpn_sel_prio = lpn->lpn_sel_priority;
                                best_lpn = lpn;
                                best_rnet = rnet;
                        }
 
-                       if (best_lpn->lpn_seq <= lpn->lpn_seq)
-                               continue;
+                       if (!best_lpn) {
+                               CERROR("peer %s has no available nets\n",
+                                      libcfs_nid2str(sd->sd_dst_nid));
+                               return -EHOSTUNREACH;
+                       }
 
-                       best_lpn = lpn;
-                       best_rnet = rnet;
-               }
+                       sd->sd_best_lpni = lnet_find_best_lpni(sd->sd_best_ni,
+                                                              sd->sd_dst_nid,
+                                                              lp,
+                                                              best_lpn->lpn_net_id);
+                       if (!sd->sd_best_lpni) {
+                               CERROR("peer %s is unreachable\n",
+                                      libcfs_nid2str(sd->sd_dst_nid));
+                               return -EHOSTUNREACH;
+                       }
 
-               if (!best_lpn) {
-                       CERROR("peer %s has no available nets\n",
-                              libcfs_nid2str(sd->sd_dst_nid));
-                       return -EHOSTUNREACH;
-               }
+                       /* We're attempting to round robin over the remote peer
+                        * NI's so update the final destination we selected
+                        */
+                       sd->sd_final_dst_lpni = sd->sd_best_lpni;
 
-               sd->sd_best_lpni = lnet_find_best_lpni(sd->sd_best_ni,
-                                                      sd->sd_dst_nid,
-                                                      lp,
-                                                      best_lpn->lpn_net_id);
-               if (!sd->sd_best_lpni) {
-                       CERROR("peer %s is unreachable\n",
-                              libcfs_nid2str(sd->sd_dst_nid));
-                       return -EHOSTUNREACH;
+                       /* Increment the sequence number of the remote lpni so
+                        * we can round robin over the different interfaces of
+                        * the remote lpni
+                        */
+                       sd->sd_best_lpni->lpni_seq++;
                }
 
                /*
-                * We're attempting to round robin over the remote peer
-                * NI's so update the final destination we selected
-                */
-               sd->sd_final_dst_lpni = sd->sd_best_lpni;
-
-               /*
                 * find the best route. Restrict the selection on the net of the
                 * local NI if we've already picked the local NI to send from.
                 * Otherwise, let's pick any route we can find and then find
-                * a local NI we can reach the route's gateway on. Any route we select
-                * will be reachable by virtue of the restriction we have when
-                * adding a route.
+                * a local NI we can reach the route's gateway on. Any route we
+                * select will be reachable by virtue of the restriction we have
+                * when adding a route.
                 */
                best_route = lnet_find_route_locked(best_rnet,
                                                    LNET_NIDNET(src_nid),
+                                                   sd->sd_best_lpni,
                                                    &last_route, &gwni);
 
                if (!best_route) {
@@ -2085,14 +2249,6 @@ lnet_handle_find_routed_path(struct lnet_send_data *sd,
 
                gw = best_route->lr_gateway;
                LASSERT(gw == gwni->lpni_peer_net->lpn_peer);
-               local_lnet = best_route->lr_lnet;
-
-               /*
-                * Increment the sequence number of the remote lpni so we
-                * can round robin over the different interfaces of the
-                * remote lpni
-                */
-               sd->sd_best_lpni->lpni_seq++;
        }
 
        /*
@@ -2100,23 +2256,20 @@ lnet_handle_find_routed_path(struct lnet_send_data *sd,
         * This means we might delay the message until discovery has
         * completed
         */
-       sd->sd_msg->msg_src_nid_param = sd->sd_src_nid;
        rc = lnet_initiate_peer_discovery(gwni, sd->sd_msg, sd->sd_cpt);
        if (rc)
                return rc;
 
-       if (!sd->sd_best_ni)
-               sd->sd_best_ni = lnet_find_best_ni_on_spec_net(NULL, gw,
-                                       lnet_peer_get_net_locked(gw,
-                                                                local_lnet),
-                                       sd->sd_md_cpt,
-                                       true);
-
        if (!sd->sd_best_ni) {
-               CERROR("Internal Error. Expected local ni on %s but non found :%s\n",
-                      libcfs_net2str(local_lnet),
-                      libcfs_nid2str(sd->sd_src_nid));
-               return -EFAULT;
+               lpn = gwni->lpni_peer_net;
+               sd->sd_best_ni = lnet_find_best_ni_on_spec_net(NULL, gw, lpn,
+                                                              sd->sd_md_cpt);
+               if (!sd->sd_best_ni) {
+                       CERROR("Internal Error. Expected local ni on %s but non found: %s\n",
+                              libcfs_net2str(lpn->lpn_net_id),
+                              libcfs_nid2str(sd->sd_src_nid));
+                       return -EFAULT;
+               }
        }
 
        *gw_lpni = gwni;
@@ -2129,7 +2282,8 @@ lnet_handle_find_routed_path(struct lnet_send_data *sd,
        if (sd->sd_rtr_nid == LNET_NID_ANY) {
                LASSERT(best_route && last_route);
                best_route->lr_seq = last_route->lr_seq + 1;
-               best_lpn->lpn_seq++;
+               if (best_lpn)
+                       best_lpn->lpn_seq++;
        }
 
        return 0;
@@ -2194,9 +2348,19 @@ struct lnet_ni *
 lnet_find_best_ni_on_local_net(struct lnet_peer *peer, int md_cpt,
                               bool discovery)
 {
-       struct lnet_peer_net *peer_net = NULL;
+       struct lnet_peer_net *lpn = NULL;
+       struct lnet_peer_net *best_lpn = NULL;
+       struct lnet_net *net = NULL;
+       struct lnet_net *best_net = NULL;
        struct lnet_ni *best_ni = NULL;
-       int lpn_healthv = 0;
+       int best_lpn_healthv = 0;
+       int best_net_healthv = 0;
+       int net_healthv;
+       __u32 best_lpn_sel_prio = LNET_MAX_SELECTION_PRIORITY;
+       __u32 lpn_sel_prio;
+       __u32 best_net_sel_prio = LNET_MAX_SELECTION_PRIORITY;
+       __u32 net_sel_prio;
+       bool exit = false;
 
        /*
         * The peer can have multiple interfaces, some of them can be on
@@ -2206,35 +2370,82 @@ lnet_find_best_ni_on_local_net(struct lnet_peer *peer, int md_cpt,
         */
 
        /* go through all the peer nets and find the best_ni */
-       list_for_each_entry(peer_net, &peer->lp_peer_nets, lpn_peer_nets) {
+       list_for_each_entry(lpn, &peer->lp_peer_nets, lpn_peer_nets) {
                /*
                 * The peer's list of nets can contain non-local nets. We
                 * want to only examine the local ones.
                 */
-               if (!lnet_get_net_locked(peer_net->lpn_net_id))
+               net = lnet_get_net_locked(lpn->lpn_net_id);
+               if (!net)
                        continue;
 
-               /* always select the lpn with the best health */
-               if (lpn_healthv <= peer_net->lpn_healthv)
-                       lpn_healthv = peer_net->lpn_healthv;
-               else
-                       continue;
-
-               best_ni = lnet_find_best_ni_on_spec_net(best_ni, peer, peer_net,
-                                                       md_cpt, false);
+               lpn_sel_prio = lpn->lpn_sel_priority;
+               net_healthv = lnet_get_net_healthv_locked(net);
+               net_sel_prio = net->net_sel_priority;
 
                /*
                 * if this is a discovery message and lp_disc_net_id is
                 * specified then use that net to send the discovery on.
                 */
-               if (peer->lp_disc_net_id == peer_net->lpn_net_id &&
-                   discovery)
+               if (peer->lp_disc_net_id == lpn->lpn_net_id &&
+                   discovery) {
+                       exit = true;
+                       goto select_lpn;
+               }
+
+               if (!best_lpn)
+                       goto select_lpn;
+
+               /* always select the lpn with the best health */
+               if (best_lpn_healthv > lpn->lpn_healthv)
+                       continue;
+               else if (best_lpn_healthv < lpn->lpn_healthv)
+                       goto select_lpn;
+
+               /* select the preferred peer and local nets */
+               if (best_lpn_sel_prio < lpn_sel_prio)
+                       continue;
+               else if (best_lpn_sel_prio > lpn_sel_prio)
+                       goto select_lpn;
+
+               if (best_net_healthv > net_healthv)
+                       continue;
+               else if (best_net_healthv < net_healthv)
+                       goto select_lpn;
+
+               if (best_net_sel_prio < net_sel_prio)
+                       continue;
+               else if (best_net_sel_prio > net_sel_prio)
+                       goto select_lpn;
+
+               if (best_lpn->lpn_seq < lpn->lpn_seq)
+                       continue;
+               else if (best_lpn->lpn_seq > lpn->lpn_seq)
+                       goto select_lpn;
+
+               /* round robin over the local networks */
+               if (best_net->net_seq <= net->net_seq)
+                       continue;
+
+select_lpn:
+               best_net_healthv = net_healthv;
+               best_net_sel_prio = net_sel_prio;
+               best_lpn_healthv = lpn->lpn_healthv;
+               best_lpn_sel_prio = lpn_sel_prio;
+               best_lpn = lpn;
+               best_net = net;
+
+               if (exit)
                        break;
        }
 
-       if (best_ni)
-               /* increment sequence number so we can round robin */
-               best_ni->ni_seq++;
+       if (best_lpn) {
+               /* Select the best NI on the same net as best_lpn chosen
+                * above
+                */
+               best_ni = lnet_find_best_ni_on_spec_net(NULL, peer,
+                                                       best_lpn, md_cpt);
+       }
 
        return best_ni;
 }
@@ -2295,7 +2506,7 @@ lnet_select_preferred_best_ni(struct lnet_send_data *sd)
                best_ni =
                  lnet_find_best_ni_on_spec_net(NULL, sd->sd_peer,
                                                sd->sd_best_lpni->lpni_peer_net,
-                                               sd->sd_md_cpt, true);
+                                               sd->sd_md_cpt);
                /* If there is no best_ni we don't have a route */
                if (!best_ni) {
                        CERROR("no path to %s from net %s\n",
@@ -2351,8 +2562,7 @@ lnet_handle_any_local_nmr_dst(struct lnet_send_data *sd)
                sd->sd_best_ni = lnet_find_best_ni_on_spec_net(NULL,
                                                               sd->sd_peer,
                                                               sd->sd_best_lpni->lpni_peer_net,
-                                                              sd->sd_md_cpt,
-                                                              true);
+                                                              sd->sd_md_cpt);
                if (!sd->sd_best_ni) {
                        CERROR("Unable to forward message to %s. No local NI available\n",
                               libcfs_nid2str(sd->sd_dst_nid));
@@ -2385,7 +2595,7 @@ lnet_handle_any_mr_dsta(struct lnet_send_data *sd)
                sd->sd_best_ni =
                  lnet_find_best_ni_on_spec_net(NULL, sd->sd_peer,
                                                sd->sd_best_lpni->lpni_peer_net,
-                                               sd->sd_md_cpt, true);
+                                               sd->sd_md_cpt);
 
                if (!sd->sd_best_ni) {
                        /*
@@ -2743,6 +2953,8 @@ again:
                 * try to send it via non-multi-rail criteria
                 */
                if (!IS_ERR(src_lpni)) {
+                       /* Drop ref taken by lnet_nid2peerni_locked() */
+                       lnet_peer_ni_decref_locked(src_lpni);
                        src_lp = lpni->lpni_peer_net->lpn_peer;
                        if (lnet_peer_is_multi_rail(src_lp) &&
                            !lnet_is_peer_ni_alive(lpni))
@@ -3136,6 +3348,7 @@ lnet_recover_local_nis(void)
        lnet_nid_t nid;
        int healthv;
        int rc;
+       time64_t now;
 
        /*
         * splice the recovery queue on a local queue. We will iterate
@@ -3149,6 +3362,8 @@ lnet_recover_local_nis(void)
                         &local_queue);
        lnet_net_unlock(0);
 
+       now = ktime_get_seconds();
+
        list_for_each_entry_safe(ni, tmp, &local_queue, ni_recovery) {
                /*
                 * if an NI is being deleted or it is now healthy, there
@@ -3182,9 +3397,15 @@ lnet_recover_local_nis(void)
                        ni->ni_recovery_state &= ~LNET_NI_RECOVERY_FAILED;
                }
 
+
                lnet_ni_unlock(ni);
-               lnet_net_unlock(0);
 
+               if (now < ni->ni_next_ping) {
+                       lnet_net_unlock(0);
+                       continue;
+               }
+
+               lnet_net_unlock(0);
 
                CDEBUG(D_NET, "attempting to recover local ni: %s\n",
                       libcfs_nid2str(ni->ni_nid));
@@ -3252,30 +3473,20 @@ lnet_recover_local_nis(void)
                                LNetMDUnlink(mdh);
                                continue;
                        }
-                       /*
-                        * Same note as in lnet_recover_peer_nis(). When
-                        * we're sending the ping, the NI is free to be
-                        * deleted or manipulated. By this point it
-                        * could've been added back on the recovery queue,
-                        * and a refcount taken on it.
-                        * So we can't just add it blindly again or we'll
-                        * corrupt the queue. We must check under lock if
-                        * it's not on any list and if not then add it
-                        * to the processed list, which will eventually be
-                        * spliced back on to the recovery queue.
-                        */
+                       ni->ni_ping_count++;
+
                        ni->ni_ping_mdh = mdh;
-                       if (list_empty(&ni->ni_recovery)) {
-                               list_add_tail(&ni->ni_recovery, &processed_list);
-                               lnet_ni_addref_locked(ni, 0);
-                       }
-                       lnet_net_unlock(0);
+                       lnet_ni_add_to_recoveryq_locked(ni, &processed_list,
+                                                       now);
 
-                       lnet_ni_lock(ni);
-                       if (rc)
+                       if (rc) {
+                               lnet_ni_lock(ni);
                                ni->ni_recovery_state &= ~LNET_NI_RECOVERY_PENDING;
-               }
-               lnet_ni_unlock(ni);
+                               lnet_ni_unlock(ni);
+                       }
+                       lnet_net_unlock(0);
+               } else
+                       lnet_ni_unlock(ni);
        }
 
        /*
@@ -3397,6 +3608,7 @@ lnet_recover_peer_nis(void)
        lnet_nid_t nid;
        int healthv;
        int rc;
+       time64_t now;
 
        /*
         * Always use cpt 0 for locking across all interactions with
@@ -3407,6 +3619,8 @@ lnet_recover_peer_nis(void)
                         &local_queue);
        lnet_net_unlock(0);
 
+       now = ktime_get_seconds();
+
        list_for_each_entry_safe(lpni, tmp, &local_queue,
                                 lpni_recovery) {
                /*
@@ -3437,6 +3651,12 @@ lnet_recover_peer_nis(void)
                }
 
                spin_unlock(&lpni->lpni_lock);
+
+               if (now < lpni->lpni_next_ping) {
+                       lnet_net_unlock(0);
+                       continue;
+               }
+
                lnet_net_unlock(0);
 
                /*
@@ -3486,30 +3706,24 @@ lnet_recover_peer_nis(void)
                                continue;
                        }
 
+                       lpni->lpni_ping_count++;
+
                        lpni->lpni_recovery_ping_mdh = mdh;
-                       /*
-                        * While we're unlocked the lpni could've been
-                        * readded on the recovery queue. In this case we
-                        * don't need to add it to the local queue, since
-                        * it's already on there and the thread that added
-                        * it would've incremented the refcount on the
-                        * peer, which means we need to decref the refcount
-                        * that was implicitly grabbed by find_peer_ni_locked.
-                        * Otherwise, if the lpni is still not on
-                        * the recovery queue, then we'll add it to the
-                        * processed list.
-                        */
-                       if (list_empty(&lpni->lpni_recovery))
-                               list_add_tail(&lpni->lpni_recovery, &processed_list);
-                       else
-                               lnet_peer_ni_decref_locked(lpni);
-                       lnet_net_unlock(0);
 
-                       spin_lock(&lpni->lpni_lock);
-                       if (rc)
+                       lnet_peer_ni_add_to_recoveryq_locked(lpni,
+                                                            &processed_list,
+                                                            now);
+                       if (rc) {
+                               spin_lock(&lpni->lpni_lock);
                                lpni->lpni_state &= ~LNET_PEER_NI_RECOVERY_PENDING;
-               }
-               spin_unlock(&lpni->lpni_lock);
+                               spin_unlock(&lpni->lpni_lock);
+                       }
+
+                       /* Drop the ref taken by lnet_find_peer_ni_locked() */
+                       lnet_peer_ni_decref_locked(lpni);
+                       lnet_net_unlock(0);
+               } else
+                       spin_unlock(&lpni->lpni_lock);
        }
 
        list_splice_init(&processed_list, &local_queue);
@@ -3521,9 +3735,7 @@ lnet_recover_peer_nis(void)
 static int
 lnet_monitor_thread(void *arg)
 {
-       time64_t recovery_timeout = 0;
        time64_t rsp_timeout = 0;
-       int interval;
        time64_t now;
 
        wait_for_completion(&the_lnet.ln_started);
@@ -3550,11 +3762,8 @@ lnet_monitor_thread(void *arg)
                        rsp_timeout = now + (lnet_transaction_timeout / 2);
                }
 
-               if (now >= recovery_timeout) {
-                       lnet_recover_local_nis();
-                       lnet_recover_peer_nis();
-                       recovery_timeout = now + lnet_recovery_interval;
-               }
+               lnet_recover_local_nis();
+               lnet_recover_peer_nis();
 
                /*
                 * TODO do we need to check if we should sleep without
@@ -3564,18 +3773,10 @@ lnet_monitor_thread(void *arg)
                 * if we wake up every 1 second? Although, we've seen
                 * cases where we get a complaint that an idle thread
                 * is waking up unnecessarily.
-                *
-                * Take into account the current net_count when you wake
-                * up for alive router checking, since we need to check
-                * possibly as many networks as we have configured.
                 */
-               interval = min(lnet_recovery_interval,
-                              min((unsigned int) alive_router_check_interval /
-                                       lnet_current_net_count,
-                                  lnet_transaction_timeout / 2));
                wait_for_completion_interruptible_timeout(
                        &the_lnet.ln_mt_wait_complete,
-                       cfs_time_seconds(interval));
+                       cfs_time_seconds(1));
                /* Must re-init the completion before testing anything,
                 * including ln_mt_state.
                 */
@@ -4360,61 +4561,6 @@ lnet_parse(struct lnet_ni *ni, struct lnet_hdr *hdr, lnet_nid_t from_nid,
                goto drop;
        }
 
-       if (lnet_drop_asym_route && for_me &&
-           LNET_NIDNET(src_nid) != LNET_NIDNET(from_nid)) {
-               struct lnet_net *net;
-               struct lnet_remotenet *rnet;
-               bool found = true;
-
-               /* we are dealing with a routed message,
-                * so see if route to reach src_nid goes through from_nid
-                */
-               lnet_net_lock(cpt);
-               net = lnet_get_net_locked(LNET_NIDNET(ni->ni_nid));
-               if (!net) {
-                       lnet_net_unlock(cpt);
-                       CERROR("net %s not found\n",
-                              libcfs_net2str(LNET_NIDNET(ni->ni_nid)));
-                       return -EPROTO;
-               }
-
-               rnet = lnet_find_rnet_locked(LNET_NIDNET(src_nid));
-               if (rnet) {
-                       struct lnet_peer *gw = NULL;
-                       struct lnet_peer_ni *lpni = NULL;
-                       struct lnet_route *route;
-
-                       list_for_each_entry(route, &rnet->lrn_routes, lr_list) {
-                               found = false;
-                               gw = route->lr_gateway;
-                               if (route->lr_lnet != net->net_id)
-                                       continue;
-                               /*
-                                * if the nid is one of the gateway's NIDs
-                                * then this is a valid gateway
-                                */
-                               while ((lpni = lnet_get_next_peer_ni_locked(gw,
-                                               NULL, lpni)) != NULL) {
-                                       if (lpni->lpni_nid == from_nid) {
-                                               found = true;
-                                               break;
-                                       }
-                               }
-                       }
-               }
-               lnet_net_unlock(cpt);
-               if (!found) {
-                       /* we would not use from_nid to route a message to
-                        * src_nid
-                        * => asymmetric routing detected but forbidden
-                        */
-                       CERROR("%s, src %s: Dropping asymmetrical route %s\n",
-                              libcfs_nid2str(from_nid),
-                              libcfs_nid2str(src_nid), lnet_msgtyp2str(type));
-                       goto drop;
-               }
-       }
-
        msg = lnet_msg_alloc();
        if (msg == NULL) {
                CERROR("%s, src %s: Dropping %s (out of memory)\n",
@@ -4465,8 +4611,65 @@ lnet_parse(struct lnet_ni *ni, struct lnet_hdr *hdr, lnet_nid_t from_nid,
                goto drop;
        }
 
-       if (the_lnet.ln_routing)
-               lpni->lpni_last_alive = ktime_get_seconds();
+       /* If this message was forwarded to us from a router then we may need
+        * to update router aliveness or check for an asymmetrical route
+        * (or both)
+        */
+       if (((lnet_drop_asym_route && for_me) ||
+            !lpni->lpni_peer_net->lpn_peer->lp_alive) &&
+           LNET_NIDNET(src_nid) != LNET_NIDNET(from_nid)) {
+               __u32 src_net_id = LNET_NIDNET(src_nid);
+               struct lnet_peer *gw = lpni->lpni_peer_net->lpn_peer;
+               struct lnet_route *route;
+               bool found = false;
+
+               list_for_each_entry(route, &gw->lp_routes, lr_gwlist) {
+                       if (route->lr_net == src_net_id) {
+                               found = true;
+                               /* If we're transitioning the gateway from
+                                * dead -> alive, and discovery is disabled
+                                * locally or on the gateway, then we need to
+                                * update the cached route aliveness for each
+                                * route to the src_nid's net.
+                                *
+                                * Otherwise, we're only checking for
+                                * symmetrical route, and we can break the
+                                * loop
+                                */
+                               if (!gw->lp_alive &&
+                                   lnet_is_discovery_disabled(gw))
+                                       lnet_set_route_aliveness(route, true);
+                               else
+                                       break;
+                       }
+               }
+               if (lnet_drop_asym_route && for_me && !found) {
+                       lnet_net_unlock(cpt);
+                       /* we would not use from_nid to route a message to
+                        * src_nid
+                        * => asymmetric routing detected but forbidden
+                        */
+                       CERROR("%s, src %s: Dropping asymmetrical route %s\n",
+                              libcfs_nid2str(from_nid),
+                              libcfs_nid2str(src_nid), lnet_msgtyp2str(type));
+                       lnet_msg_free(msg);
+                       goto drop;
+               }
+               if (!gw->lp_alive) {
+                       struct lnet_peer_net *lpn;
+                       struct lnet_peer_ni *lpni2;
+
+                       gw->lp_alive = true;
+                       /* Mark all remote NIs on src_nid's net UP */
+                       lpn = lnet_peer_get_net_locked(gw, src_net_id);
+                       if (lpn)
+                               list_for_each_entry(lpni2, &lpn->lpn_peer_nis,
+                                                   lpni_peer_nis)
+                                       lpni2->lpni_ns_status = LNET_NI_STATUS_UP;
+               }
+       }
+
+       lpni->lpni_last_alive = ktime_get_seconds();
 
        msg->msg_rxpeer = lpni;
        msg->msg_rxni = ni;
@@ -4739,7 +4942,9 @@ LNetPut(lnet_nid_t self, struct lnet_handle_md mdh, enum lnet_ack_req ack,
                               md->md_me->me_portal);
                lnet_res_unlock(cpt);
 
-               lnet_rspt_free(rspt, cpt);
+               if (rspt)
+                       lnet_rspt_free(rspt, cpt);
+
                lnet_msg_free(msg);
                return -ENOENT;
        }
@@ -4772,8 +4977,11 @@ LNetPut(lnet_nid_t self, struct lnet_handle_md mdh, enum lnet_ack_req ack,
 
        lnet_build_msg_event(msg, LNET_EVENT_SEND);
 
-       if (ack == LNET_ACK_REQ)
+       if (rspt && lnet_response_tracking_enabled(LNET_MSG_PUT,
+                                                  md->md_options))
                lnet_attach_rsp_tracker(rspt, cpt, md, mdh);
+       else if (rspt)
+               lnet_rspt_free(rspt, cpt);
 
        if (CFS_FAIL_CHECK_ORSET(CFS_FAIL_PTLRPC_OST_BULK_CB2,
                                 CFS_FAIL_ONCE))
@@ -4991,7 +5199,10 @@ LNetGet(lnet_nid_t self, struct lnet_handle_md mdh,
 
        lnet_build_msg_event(msg, LNET_EVENT_SEND);
 
-       lnet_attach_rsp_tracker(rspt, cpt, md, mdh);
+       if (lnet_response_tracking_enabled(LNET_MSG_GET, md->md_options))
+               lnet_attach_rsp_tracker(rspt, cpt, md, mdh);
+       else
+               lnet_rspt_free(rspt, cpt);
 
        rc = lnet_send(self, msg, LNET_NID_ANY);
        if (rc < 0) {
@@ -5031,6 +5242,7 @@ LNetDist(lnet_nid_t dstnid, lnet_nid_t *srcnidp, __u32 *orderp)
        int cpt;
        __u32 order = 2;
        struct list_head *rn_list;
+       bool matched_dstnet = false;
 
        /* if !local_nid_dist_zero, I don't return a distance of 0 ever
         * (when lustre sees a distance of 0, it substitutes 0@lo), so I
@@ -5056,25 +5268,40 @@ LNetDist(lnet_nid_t dstnid, lnet_nid_t *srcnidp, __u32 *orderp)
                        return local_nid_dist_zero ? 0 : 1;
                }
 
-               if (LNET_NIDNET(ni->ni_nid) == dstnet) {
-                       /* Check if ni was originally created in
-                        * current net namespace.
-                        * If not, assign order above 0xffff0000,
-                        * to make this ni not a priority. */
-                       if (current->nsproxy &&
-                           !net_eq(ni->ni_net_ns, current->nsproxy->net_ns))
-                                       order += 0xffff0000;
-                       if (srcnidp != NULL)
+               if (!matched_dstnet && LNET_NIDNET(ni->ni_nid) == dstnet) {
+                       matched_dstnet = true;
+                       /* We matched the destination net, but we may have
+                        * additional local NIs to inspect.
+                        *
+                        * We record the nid and order as appropriate, but
+                        * they may be overwritten if we match local NI above.
+                        */
+                       if (srcnidp)
                                *srcnidp = ni->ni_nid;
-                       if (orderp != NULL)
-                               *orderp = order;
-                       lnet_net_unlock(cpt);
-                       return 1;
+
+                       if (orderp) {
+                               /* Check if ni was originally created in
+                                * current net namespace.
+                                * If not, assign order above 0xffff0000,
+                                * to make this ni not a priority.
+                                */
+                               if (current->nsproxy &&
+                                   !net_eq(ni->ni_net_ns,
+                                           current->nsproxy->net_ns))
+                                       *orderp = order + 0xffff0000;
+                               else
+                                       *orderp = order;
+                       }
                }
 
                order++;
        }
 
+       if (matched_dstnet) {
+               lnet_net_unlock(cpt);
+               return 1;
+       }
+
        rn_list = lnet_net2rnethash(dstnet);
        list_for_each(e, rn_list) {
                rnet = list_entry(e, struct lnet_remotenet, lrn_list);