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LU-14627 lnet: Ensure ref taken when queueing for discovery
[fs/lustre-release.git] / lnet / lnet / peer.c
index ff2ce69..709fe24 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/peer.c
  */
@@ -169,7 +168,7 @@ lnet_peer_ni_alloc(lnet_nid_t nid)
        INIT_LIST_HEAD(&lpni->lpni_on_remote_peer_ni_list);
        INIT_LIST_HEAD(&lpni->lpni_rtr_pref_nids);
        LNetInvalidateMDHandle(&lpni->lpni_recovery_ping_mdh);
-       atomic_set(&lpni->lpni_refcount, 1);
+       kref_init(&lpni->lpni_kref);
        lpni->lpni_sel_priority = LNET_MAX_SELECTION_PRIORITY;
 
        spin_lock_init(&lpni->lpni_lock);
@@ -264,6 +263,7 @@ lnet_peer_alloc(lnet_nid_t nid)
        spin_lock_init(&lp->lp_lock);
        lp->lp_primary_nid = nid;
        lp->lp_disc_src_nid = LNET_NID_ANY;
+       lp->lp_disc_dst_nid = LNET_NID_ANY;
        if (lnet_peers_start_down())
                lp->lp_alive = false;
        else
@@ -459,6 +459,10 @@ lnet_peer_del_locked(struct lnet_peer *peer)
 
        CDEBUG(D_NET, "peer %s\n", libcfs_nid2str(peer->lp_primary_nid));
 
+       spin_lock(&peer->lp_lock);
+       peer->lp_state |= LNET_PEER_MARK_DELETED;
+       spin_unlock(&peer->lp_lock);
+
        lpni = lnet_get_next_peer_ni_locked(peer, NULL, lpni);
        while (lpni != NULL) {
                lpni2 = lnet_get_next_peer_ni_locked(peer, NULL, lpni);
@@ -471,9 +475,41 @@ lnet_peer_del_locked(struct lnet_peer *peer)
        return rc2;
 }
 
+/*
+ * Discovering this peer is taking too long. Cancel any Ping or Push
+ * that discovery is waiting on by unlinking the relevant MDs. The
+ * lnet_discovery_event_handler() will proceed from here and complete
+ * the cleanup.
+ */
+static void lnet_peer_cancel_discovery(struct lnet_peer *lp)
+{
+       struct lnet_handle_md ping_mdh;
+       struct lnet_handle_md push_mdh;
+
+       LNetInvalidateMDHandle(&ping_mdh);
+       LNetInvalidateMDHandle(&push_mdh);
+
+       spin_lock(&lp->lp_lock);
+       if (lp->lp_state & LNET_PEER_PING_SENT) {
+               ping_mdh = lp->lp_ping_mdh;
+               LNetInvalidateMDHandle(&lp->lp_ping_mdh);
+       }
+       if (lp->lp_state & LNET_PEER_PUSH_SENT) {
+               push_mdh = lp->lp_push_mdh;
+               LNetInvalidateMDHandle(&lp->lp_push_mdh);
+       }
+       spin_unlock(&lp->lp_lock);
+
+       if (!LNetMDHandleIsInvalid(ping_mdh))
+               LNetMDUnlink(ping_mdh);
+       if (!LNetMDHandleIsInvalid(push_mdh))
+               LNetMDUnlink(push_mdh);
+}
+
 static int
 lnet_peer_del(struct lnet_peer *peer)
 {
+       lnet_peer_cancel_discovery(peer);
        lnet_net_lock(LNET_LOCK_EX);
        lnet_peer_del_locked(peer);
        lnet_net_unlock(LNET_LOCK_EX);
@@ -1312,7 +1348,13 @@ LNetPrimaryNID(lnet_nid_t nid)
        }
        lp = lpni->lpni_peer_net->lpn_peer;
 
-       while (!lnet_peer_is_uptodate(lp)) {
+       /* If discovery is disabled locally then we needn't bother running
+        * discovery here because discovery will not modify whatever
+        * primary NID is currently set for this peer. If the specified peer is
+        * down then this discovery can introduce long delays into the mount
+        * process, so skip it if it isn't necessary.
+        */
+       while (!lnet_peer_discovery_disabled && !lnet_peer_is_uptodate(lp)) {
                spin_lock(&lp->lp_lock);
                /* force a full discovery cycle */
                lp->lp_state |= LNET_PEER_FORCE_PING | LNET_PEER_FORCE_PUSH;
@@ -1321,9 +1363,23 @@ LNetPrimaryNID(lnet_nid_t nid)
                rc = lnet_discover_peer_locked(lpni, cpt, true);
                if (rc)
                        goto out_decref;
+               /* The lpni (or lp) for this NID may have changed and our ref is
+                * the only thing keeping the old one around. Release the ref
+                * and lookup the lpni again
+                */
+               lnet_peer_ni_decref_locked(lpni);
+               lpni = lnet_find_peer_ni_locked(nid);
+               if (!lpni) {
+                       rc = -ENOENT;
+                       goto out_unlock;
+               }
                lp = lpni->lpni_peer_net->lpn_peer;
 
-               /* Only try once if discovery is disabled */
+               /* If we find that the peer has discovery disabled then we will
+                * not modify whatever primary NID is currently set for this
+                * peer. Thus, we can break out of this loop even if the peer
+                * is not fully up to date.
+                */
                if (lnet_is_discovery_disabled(lp))
                        break;
        }
@@ -1393,7 +1449,10 @@ lnet_peer_attach_peer_ni(struct lnet_peer *lp,
 
        /* Add peer_ni to peer_net */
        lpni->lpni_peer_net = lpn;
-       list_add_tail(&lpni->lpni_peer_nis, &lpn->lpn_peer_nis);
+       if (lp->lp_primary_nid == lpni->lpni_nid)
+               list_add(&lpni->lpni_peer_nis, &lpn->lpn_peer_nis);
+       else
+               list_add_tail(&lpni->lpni_peer_nis, &lpn->lpn_peer_nis);
        lnet_update_peer_net_healthv(lpni);
        lnet_peer_net_addref_locked(lpn);
 
@@ -1401,7 +1460,10 @@ lnet_peer_attach_peer_ni(struct lnet_peer *lp,
        if (!lpn->lpn_peer) {
                new_lpn = true;
                lpn->lpn_peer = lp;
-               list_add_tail(&lpn->lpn_peer_nets, &lp->lp_peer_nets);
+               if (lp->lp_primary_nid == lpni->lpni_nid)
+                       list_add(&lpn->lpn_peer_nets, &lp->lp_peer_nets);
+               else
+                       list_add_tail(&lpn->lpn_peer_nets, &lp->lp_peer_nets);
                lnet_peer_addref_locked(lp);
        }
 
@@ -1642,10 +1704,14 @@ lnet_peer_set_primary_nid(struct lnet_peer *lp, lnet_nid_t nid, unsigned flags)
 
        if (lp->lp_primary_nid == nid)
                goto out;
+
+       lp->lp_primary_nid = nid;
+
        rc = lnet_peer_add_nid(lp, nid, flags);
-       if (rc)
+       if (rc) {
+               lp->lp_primary_nid = old;
                goto out;
-       lp->lp_primary_nid = nid;
+       }
 out:
        CDEBUG(D_NET, "peer %s NID %s: %d\n",
               libcfs_nid2str(old), libcfs_nid2str(nid), rc);
@@ -1827,14 +1893,16 @@ lnet_del_peer_ni(lnet_nid_t prim_nid, lnet_nid_t nid)
 }
 
 void
-lnet_destroy_peer_ni_locked(struct lnet_peer_ni *lpni)
+lnet_destroy_peer_ni_locked(struct kref *ref)
 {
+       struct lnet_peer_ni *lpni = container_of(ref, struct lnet_peer_ni,
+                                                lpni_kref);
        struct lnet_peer_table *ptable;
        struct lnet_peer_net *lpn;
 
        CDEBUG(D_NET, "%p nid %s\n", lpni, libcfs_nid2str(lpni->lpni_nid));
 
-       LASSERT(atomic_read(&lpni->lpni_refcount) == 0);
+       LASSERT(kref_read(&lpni->lpni_kref) == 0);
        LASSERT(list_empty(&lpni->lpni_txq));
        LASSERT(lpni->lpni_txqnob == 0);
        LASSERT(list_empty(&lpni->lpni_peer_nis));
@@ -2027,6 +2095,26 @@ __must_hold(&lp->lp_lock)
        return rc;
 }
 
+/* Add the message to the peer's lp_dc_pendq and queue the peer for discovery */
+void
+lnet_peer_queue_message(struct lnet_peer *lp, struct lnet_msg *msg)
+{
+       /* The discovery thread holds net_lock/EX and lp_lock when it splices
+        * the lp_dc_pendq onto a local list for resending. Thus, we do the same
+        * when adding to the list and queuing the peer to ensure that we do not
+        * strand any messages on the lp_dc_pendq. This scheme ensures the
+        * message will be resent even if the peer is already being discovered.
+        * Therefore we needn't check the return value of
+        * lnet_peer_queue_for_discovery(lp).
+        */
+       lnet_net_lock(LNET_LOCK_EX);
+       spin_lock(&lp->lp_lock);
+       list_add_tail(&msg->msg_list, &lp->lp_dc_pendq);
+       spin_unlock(&lp->lp_lock);
+       lnet_peer_queue_for_discovery(lp);
+       lnet_net_unlock(LNET_LOCK_EX);
+}
+
 /*
  * Queue a peer for the attention of the discovery thread.  Call with
  * lnet_net_lock/EX held. Returns 0 if the peer was queued, and
@@ -2072,7 +2160,7 @@ static void lnet_peer_discovery_complete(struct lnet_peer *lp)
        spin_lock(&lp->lp_lock);
        list_splice_init(&lp->lp_dc_pendq, &pending_msgs);
        spin_unlock(&lp->lp_lock);
-       wake_up_all(&lp->lp_dc_waitq);
+       wake_up(&lp->lp_dc_waitq);
 
        if (lp->lp_rtr_refcount > 0)
                lnet_router_discovery_complete(lp);
@@ -2444,6 +2532,7 @@ lnet_discovery_event_reply(struct lnet_peer *lp, struct lnet_event *ev)
        spin_lock(&lp->lp_lock);
 
        lp->lp_disc_src_nid = ev->target.nid;
+       lp->lp_disc_dst_nid = ev->source.nid;
 
        /*
         * If some kind of error happened the contents of message
@@ -2476,20 +2565,41 @@ lnet_discovery_event_reply(struct lnet_peer *lp, struct lnet_event *ev)
                goto out;
        }
 
-
        /*
         * The peer may have discovery disabled at its end. Set
         * NO_DISCOVERY as appropriate.
         */
-       if ((pbuf->pb_info.pi_features & LNET_PING_FEAT_DISCOVERY) &&
-           !lnet_peer_discovery_disabled) {
-               CDEBUG(D_NET, "Peer %s has discovery enabled\n",
-                      libcfs_nid2str(lp->lp_primary_nid));
-               lp->lp_state &= ~LNET_PEER_NO_DISCOVERY;
-       } else {
+       if (!(pbuf->pb_info.pi_features & LNET_PING_FEAT_DISCOVERY) ||
+           lnet_peer_discovery_disabled) {
                CDEBUG(D_NET, "Peer %s has discovery disabled\n",
                       libcfs_nid2str(lp->lp_primary_nid));
+
+               /* Detect whether this peer has toggled discovery from on to
+                * off and whether we can delete and re-create the peer. Peers
+                * that were manually configured cannot be deleted by discovery.
+                * We need to delete this peer and re-create it if the peer was
+                * not configured manually, is currently considered DD capable,
+                * and either:
+                * 1. We've already discovered the peer (the peer has toggled
+                *    the discovery feature from on to off), or
+                * 2. The peer is considered MR, but it was not user configured
+                *    (this was a "temporary" peer created via the kernel APIs
+                *     that we're discovering for the first time)
+                */
+               if (!(lp->lp_state & (LNET_PEER_CONFIGURED |
+                                     LNET_PEER_NO_DISCOVERY)) &&
+                   (lp->lp_state & (LNET_PEER_DISCOVERED |
+                                    LNET_PEER_MULTI_RAIL))) {
+                       CDEBUG(D_NET, "Marking %s:0x%x for deletion\n",
+                              libcfs_nid2str(lp->lp_primary_nid),
+                              lp->lp_state);
+                       lp->lp_state |= LNET_PEER_MARK_DELETION;
+               }
                lp->lp_state |= LNET_PEER_NO_DISCOVERY;
+       } else {
+               CDEBUG(D_NET, "Peer %s has discovery enabled\n",
+                      libcfs_nid2str(lp->lp_primary_nid));
+               lp->lp_state &= ~LNET_PEER_NO_DISCOVERY;
        }
 
        /*
@@ -2697,7 +2807,8 @@ static void lnet_discovery_event_handler(struct lnet_event *event)
 
        /* put peer back at end of request queue, if discovery not already
         * done */
-       if (rc == LNET_REDISCOVER_PEER && !lnet_peer_is_uptodate(lp)) {
+       if (rc == LNET_REDISCOVER_PEER && !lnet_peer_is_uptodate(lp) &&
+           lnet_peer_queue_for_discovery(lp)) {
                list_move_tail(&lp->lp_dc_list, &the_lnet.ln_dc_request);
                wake_up(&the_lnet.ln_dc_waitq);
        }
@@ -2725,6 +2836,7 @@ static void lnet_discovery_event_handler(struct lnet_event *event)
 static int lnet_peer_merge_data(struct lnet_peer *lp,
                                struct lnet_ping_buffer *pbuf)
 {
+       struct lnet_peer_net *lpn;
        struct lnet_peer_ni *lpni;
        lnet_nid_t *curnis = NULL;
        struct lnet_ni_status *addnis = NULL;
@@ -2853,6 +2965,28 @@ static int lnet_peer_merge_data(struct lnet_peer *lp,
                                goto out;
                }
        }
+
+       /* The peer net for the primary NID should be the first entry in the
+        * peer's lp_peer_nets list, and the peer NI for the primary NID should
+        * be the first entry in its peer net's lpn_peer_nis list.
+        */
+       lpni = lnet_find_peer_ni_locked(pbuf->pb_info.pi_ni[1].ns_nid);
+       if (!lpni) {
+               CERROR("Internal error: Failed to lookup peer NI for primary NID: %s\n",
+                      libcfs_nid2str(pbuf->pb_info.pi_ni[1].ns_nid));
+               goto out;
+       }
+
+       lnet_peer_ni_decref_locked(lpni);
+
+       lpn = lpni->lpni_peer_net;
+       if (lpn->lpn_peer_nets.prev != &lp->lp_peer_nets)
+               list_move(&lpn->lpn_peer_nets, &lp->lp_peer_nets);
+
+       if (lpni->lpni_peer_nis.prev != &lpni->lpni_peer_net->lpn_peer_nis)
+               list_move(&lpni->lpni_peer_nis,
+                         &lpni->lpni_peer_net->lpn_peer_nis);
+
        /*
         * Errors other than -ENOMEM are due to peers having been
         * configured with DLC. Ignore these because DLC overrides
@@ -2970,6 +3104,10 @@ __must_hold(&lp->lp_lock)
        CDEBUG(D_NET, "peer %s(%p) state %#x\n",
               libcfs_nid2str(lp->lp_primary_nid), lp, lp->lp_state);
 
+       /* no-op if lnet_peer_del() has already been called on this peer */
+       if (lp->lp_state & LNET_PEER_MARK_DELETED)
+               return 0;
+
        if (the_lnet.ln_dc_state != LNET_DC_STATE_RUNNING)
                return -ESHUTDOWN;
 
@@ -2983,7 +3121,7 @@ __must_hold(&lp->lp_lock)
         * of deleting it.
         */
        if (!list_empty(&lp->lp_dc_list))
-               list_del(&lp->lp_dc_list);
+               list_del_init(&lp->lp_dc_list);
        list_for_each_entry_safe(route, tmp,
                                 &lp->lp_routes,
                                 lr_gwlist)
@@ -3092,7 +3230,7 @@ __must_hold(&lp->lp_lock)
                rc = lnet_peer_merge_data(lp, pbuf);
        } else {
                lpni = lnet_find_peer_ni_locked(nid);
-               if (!lpni) {
+               if (!lpni || lp == lpni->lpni_peer_net->lpn_peer) {
                        rc = lnet_peer_set_primary_nid(lp, nid, flags);
                        if (rc) {
                                CERROR("Primary NID error %s versus %s: %d\n",
@@ -3101,6 +3239,8 @@ __must_hold(&lp->lp_lock)
                        } else {
                                rc = lnet_peer_merge_data(lp, pbuf);
                        }
+                       if (lpni)
+                               lnet_peer_ni_decref_locked(lpni);
                } else {
                        struct lnet_peer *new_lp;
                        new_lp = lpni->lpni_peer_net->lpn_peer;
@@ -3109,10 +3249,24 @@ __must_hold(&lp->lp_lock)
                         * should have discovery/MR enabled as well, since
                         * it's the same peer, which we're about to merge
                         */
+                       spin_lock(&lp->lp_lock);
+                       spin_lock(&new_lp->lp_lock);
                        if (!(lp->lp_state & LNET_PEER_NO_DISCOVERY))
                                new_lp->lp_state &= ~LNET_PEER_NO_DISCOVERY;
                        if (lp->lp_state & LNET_PEER_MULTI_RAIL)
                                new_lp->lp_state |= LNET_PEER_MULTI_RAIL;
+                       /* If we're processing a ping reply then we may be
+                        * about to send a push to the peer that we ping'd.
+                        * Since the ping reply that we're processing was
+                        * received by lp, we need to set the discovery source
+                        * NID for new_lp to the NID stored in lp.
+                        */
+                       if (lp->lp_disc_src_nid != LNET_NID_ANY) {
+                               new_lp->lp_disc_src_nid = lp->lp_disc_src_nid;
+                               new_lp->lp_disc_dst_nid = lp->lp_disc_dst_nid;
+                       }
+                       spin_unlock(&new_lp->lp_lock);
+                       spin_unlock(&lp->lp_lock);
 
                        rc = lnet_peer_set_primary_data(new_lp, pbuf);
                        lnet_consolidate_routes_locked(lp, new_lp);
@@ -3160,41 +3314,10 @@ __must_hold(&lp->lp_lock)
        return rc ? rc : LNET_REDISCOVER_PEER;
 }
 
-/*
- * Select NID to send a Ping or Push to.
- */
-static lnet_nid_t lnet_peer_select_nid(struct lnet_peer *lp)
-{
-       struct lnet_peer_ni *lpni;
-
-       /* Look for a direct-connected NID for this peer. */
-       lpni = NULL;
-       while ((lpni = lnet_get_next_peer_ni_locked(lp, NULL, lpni)) != NULL) {
-               if (!lnet_get_net_locked(lpni->lpni_peer_net->lpn_net_id))
-                       continue;
-               break;
-       }
-       if (lpni)
-               return lpni->lpni_nid;
-
-       /* Look for a routed-connected NID for this peer. */
-       lpni = NULL;
-       while ((lpni = lnet_get_next_peer_ni_locked(lp, NULL, lpni)) != NULL) {
-               if (!lnet_find_rnet_locked(lpni->lpni_peer_net->lpn_net_id))
-                       continue;
-               break;
-       }
-       if (lpni)
-               return lpni->lpni_nid;
-
-       return LNET_NID_ANY;
-}
-
 /* Active side of ping. */
 static int lnet_peer_send_ping(struct lnet_peer *lp)
 __must_hold(&lp->lp_lock)
 {
-       lnet_nid_t pnid;
        int nnis;
        int rc;
        int cpt;
@@ -3206,12 +3329,11 @@ __must_hold(&lp->lp_lock)
        cpt = lnet_net_lock_current();
        /* Refcount for MD. */
        lnet_peer_addref_locked(lp);
-       pnid = lnet_peer_select_nid(lp);
        lnet_net_unlock(cpt);
 
        nnis = max(lp->lp_data_nnis, LNET_INTERFACES_MIN);
 
-       rc = lnet_send_ping(pnid, &lp->lp_ping_mdh, nnis, lp,
+       rc = lnet_send_ping(lp->lp_primary_nid, &lp->lp_ping_mdh, nnis, lp,
                            the_lnet.ln_dc_handler, false);
 
        /*
@@ -3336,18 +3458,17 @@ __must_hold(&lp->lp_lock)
                CERROR("Can't bind push source MD: %d\n", rc);
                goto fail_error;
        }
+
        cpt = lnet_net_lock_current();
        /* Refcount for MD. */
        lnet_peer_addref_locked(lp);
        id.pid = LNET_PID_LUSTRE;
-       id.nid = lnet_peer_select_nid(lp);
+       if (lp->lp_disc_dst_nid != LNET_NID_ANY)
+               id.nid = lp->lp_disc_dst_nid;
+       else
+               id.nid = lp->lp_primary_nid;
        lnet_net_unlock(cpt);
 
-       if (id.nid == LNET_NID_ANY) {
-               rc = -EHOSTUNREACH;
-               goto fail_unlink;
-       }
-
        rc = LNetPut(lp->lp_disc_src_nid, lp->lp_push_mdh,
                     LNET_ACK_REQ, id, LNET_RESERVED_PORTAL,
                     LNET_PROTO_PING_MATCHBITS, 0, 0);
@@ -3359,6 +3480,7 @@ __must_hold(&lp->lp_lock)
         * scratch
         */
        lp->lp_disc_src_nid = LNET_NID_ANY;
+       lp->lp_disc_dst_nid = LNET_NID_ANY;
 
        if (rc)
                goto fail_unlink;
@@ -3402,37 +3524,6 @@ static void lnet_peer_discovery_error(struct lnet_peer *lp, int error)
 }
 
 /*
- * Discovering this peer is taking too long. Cancel any Ping or Push
- * that discovery is waiting on by unlinking the relevant MDs. The
- * lnet_discovery_event_handler() will proceed from here and complete
- * the cleanup.
- */
-static void lnet_peer_cancel_discovery(struct lnet_peer *lp)
-{
-       struct lnet_handle_md ping_mdh;
-       struct lnet_handle_md push_mdh;
-
-       LNetInvalidateMDHandle(&ping_mdh);
-       LNetInvalidateMDHandle(&push_mdh);
-
-       spin_lock(&lp->lp_lock);
-       if (lp->lp_state & LNET_PEER_PING_SENT) {
-               ping_mdh = lp->lp_ping_mdh;
-               LNetInvalidateMDHandle(&lp->lp_ping_mdh);
-       }
-       if (lp->lp_state & LNET_PEER_PUSH_SENT) {
-               push_mdh = lp->lp_push_mdh;
-               LNetInvalidateMDHandle(&lp->lp_push_mdh);
-       }
-       spin_unlock(&lp->lp_lock);
-
-       if (!LNetMDHandleIsInvalid(ping_mdh))
-               LNetMDUnlink(ping_mdh);
-       if (!LNetMDHandleIsInvalid(push_mdh))
-               LNetMDUnlink(push_mdh);
-}
-
-/*
  * Wait for work to be queued or some other change that must be
  * attended to. Returns non-zero if the discovery thread should shut
  * down.
@@ -3588,7 +3679,8 @@ static int lnet_peer_discovery(void *arg)
                        CDEBUG(D_NET, "peer %s(%p) state %#x\n",
                                libcfs_nid2str(lp->lp_primary_nid), lp,
                                lp->lp_state);
-                       if (lp->lp_state & LNET_PEER_MARK_DELETION)
+                       if (lp->lp_state & (LNET_PEER_MARK_DELETION |
+                                           LNET_PEER_MARK_DELETED))
                                rc = lnet_peer_deletion(lp);
                        else if (lp->lp_state & LNET_PEER_DATA_PRESENT)
                                rc = lnet_peer_data_present(lp);
@@ -3749,7 +3841,7 @@ lnet_debug_peer(lnet_nid_t nid)
                aliveness = (lnet_is_peer_ni_alive(lp)) ? "up" : "down";
 
        CDEBUG(D_WARNING, "%-24s %4d %5s %5d %5d %5d %5d %5d %ld\n",
-              libcfs_nid2str(lp->lpni_nid), atomic_read(&lp->lpni_refcount),
+              libcfs_nid2str(lp->lpni_nid), kref_read(&lp->lpni_kref),
               aliveness, lp->lpni_net->net_tunables.lct_peer_tx_credits,
               lp->lpni_rtrcredits, lp->lpni_minrtrcredits,
               lp->lpni_txcredits, lp->lpni_mintxcredits, lp->lpni_txqnob);
@@ -3805,7 +3897,7 @@ int lnet_get_peer_ni_info(__u32 peer_index, __u64 *nid,
                                         lnet_is_peer_ni_alive(lp) ? "up" : "down");
 
                        *nid = lp->lpni_nid;
-                       *refcount = atomic_read(&lp->lpni_refcount);
+                       *refcount = kref_read(&lp->lpni_kref);
                        *ni_peer_tx_credits =
                                lp->lpni_net->net_tunables.lct_peer_tx_credits;
                        *peer_tx_credits = lp->lpni_txcredits;
@@ -3891,7 +3983,7 @@ int lnet_get_peer_info(struct lnet_ioctl_peer_cfg *cfg, void __user *bulk)
                        snprintf(lpni_info->cr_aliveness, LNET_MAX_STR_LEN,
                                lnet_is_peer_ni_alive(lpni) ? "up" : "down");
 
-               lpni_info->cr_refcount = atomic_read(&lpni->lpni_refcount);
+               lpni_info->cr_refcount = kref_read(&lpni->lpni_kref);
                lpni_info->cr_ni_peer_tx_credits = (lpni->lpni_net != NULL) ?
                        lpni->lpni_net->net_tunables.lct_peer_tx_credits : 0;
                lpni_info->cr_peer_tx_credits = lpni->lpni_txcredits;
@@ -3927,6 +4019,8 @@ int lnet_get_peer_info(struct lnet_ioctl_peer_cfg *cfg, void __user *bulk)
                  atomic_read(&lpni->lpni_hstats.hlt_remote_error);
                lpni_hstats->hlpni_health_value =
                  atomic_read(&lpni->lpni_healthv);
+               lpni_hstats->hlpni_ping_count = lpni->lpni_ping_count;
+               lpni_hstats->hlpni_next_ping = lpni->lpni_next_ping;
                if (copy_to_user(bulk, lpni_hstats, sizeof(*lpni_hstats)))
                        goto out_free_hstats;
                bulk += sizeof(*lpni_hstats);
@@ -3947,21 +4041,54 @@ out:
        return rc;
 }
 
+/* must hold net_lock/0 */
 void
-lnet_peer_ni_add_to_recoveryq_locked(struct lnet_peer_ni *lpni)
+lnet_peer_ni_add_to_recoveryq_locked(struct lnet_peer_ni *lpni,
+                                    struct list_head *recovery_queue,
+                                    time64_t now)
 {
        /* the mt could've shutdown and cleaned up the queues */
        if (the_lnet.ln_mt_state != LNET_MT_STATE_RUNNING)
                return;
 
-       if (list_empty(&lpni->lpni_recovery) &&
-           atomic_read(&lpni->lpni_healthv) < LNET_MAX_HEALTH_VALUE) {
-               CDEBUG(D_NET, "lpni %s added to recovery queue. Health = %d\n",
-                       libcfs_nid2str(lpni->lpni_nid),
-                       atomic_read(&lpni->lpni_healthv));
-               list_add_tail(&lpni->lpni_recovery, &the_lnet.ln_mt_peerNIRecovq);
-               lnet_peer_ni_addref_locked(lpni);
+       if (!list_empty(&lpni->lpni_recovery))
+               return;
+
+       if (atomic_read(&lpni->lpni_healthv) == LNET_MAX_HEALTH_VALUE)
+               return;
+
+       if (!lpni->lpni_last_alive) {
+               CDEBUG(D_NET,
+                      "lpni %s(%p) not eligible for recovery last alive %lld\n",
+                      libcfs_nid2str(lpni->lpni_nid), lpni,
+                      lpni->lpni_last_alive);
+               return;
        }
+
+       if (now > lpni->lpni_last_alive + lnet_recovery_limit) {
+               CDEBUG(D_NET, "lpni %s aged out last alive %lld\n",
+                      libcfs_nid2str(lpni->lpni_nid),
+                      lpni->lpni_last_alive);
+               /* Reset the ping count so that if this peer NI is added back to
+                * the recovery queue we will send the first ping right away.
+                */
+               lpni->lpni_ping_count = 0;
+               return;
+       }
+
+       /* This peer NI is going on the recovery queue, so take a ref on it */
+       lnet_peer_ni_addref_locked(lpni);
+
+       lnet_peer_ni_set_next_ping(lpni, now);
+
+       CDEBUG(D_NET, "%s added to recovery queue. ping count: %u next ping: %lld last alive: %lld health: %d\n",
+              libcfs_nid2str(lpni->lpni_nid),
+              lpni->lpni_ping_count,
+              lpni->lpni_next_ping,
+              lpni->lpni_last_alive,
+              atomic_read(&lpni->lpni_healthv));
+
+       list_add_tail(&lpni->lpni_recovery, recovery_queue);
 }
 
 /* Call with the ln_api_mutex held */
@@ -3974,10 +4101,13 @@ lnet_peer_ni_set_healthv(lnet_nid_t nid, int value, bool all)
        struct lnet_peer_ni *lpni;
        int lncpt;
        int cpt;
+       time64_t now;
 
        if (the_lnet.ln_state != LNET_STATE_RUNNING)
                return;
 
+       now = ktime_get_seconds();
+
        if (!all) {
                lnet_net_lock(LNET_LOCK_EX);
                lpni = lnet_find_peer_ni_locked(nid);
@@ -3985,8 +4115,9 @@ lnet_peer_ni_set_healthv(lnet_nid_t nid, int value, bool all)
                        lnet_net_unlock(LNET_LOCK_EX);
                        return;
                }
-               atomic_set(&lpni->lpni_healthv, value);
-               lnet_peer_ni_add_to_recoveryq_locked(lpni);
+               lnet_set_lpni_healthv_locked(lpni, value);
+               lnet_peer_ni_add_to_recoveryq_locked(lpni,
+                                            &the_lnet.ln_mt_peerNIRecovq, now);
                lnet_peer_ni_decref_locked(lpni);
                lnet_net_unlock(LNET_LOCK_EX);
                return;
@@ -3995,8 +4126,8 @@ lnet_peer_ni_set_healthv(lnet_nid_t nid, int value, bool all)
        lncpt = cfs_percpt_number(the_lnet.ln_peer_tables);
 
        /*
-        * Walk all the peers and reset the healhv for each one to the
-        * maximum value.
+        * Walk all the peers and reset the health value for each one to the
+        * specified value.
         */
        lnet_net_lock(LNET_LOCK_EX);
        for (cpt = 0; cpt < lncpt; cpt++) {
@@ -4005,8 +4136,10 @@ lnet_peer_ni_set_healthv(lnet_nid_t nid, int value, bool all)
                        list_for_each_entry(lpn, &lp->lp_peer_nets, lpn_peer_nets) {
                                list_for_each_entry(lpni, &lpn->lpn_peer_nis,
                                                    lpni_peer_nis) {
-                                       atomic_set(&lpni->lpni_healthv, value);
-                                       lnet_peer_ni_add_to_recoveryq_locked(lpni);
+                                       lnet_set_lpni_healthv_locked(lpni,
+                                                                    value);
+                                       lnet_peer_ni_add_to_recoveryq_locked(lpni,
+                                            &the_lnet.ln_mt_peerNIRecovq, now);
                                }
                        }
                }