LU-7646 o2iblnd: connrace protocol improvement

[fs/lustre-release.git] / lnet / klnds / o2iblnd / o2iblnd.h

diff --git a/lnet/klnds/o2iblnd/o2iblnd.h b/lnet/klnds/o2iblnd/o2iblnd.h
index b3d9332..cc16452 100644 (file)
--- a/lnet/klnds/o2iblnd/o2iblnd.h
+++ b/lnet/klnds/o2iblnd/o2iblnd.h
@@ -531,6 +531,11 @@ typedef struct
 #define IBLND_MSG_GET_REQ           0xd6        /* getreq (sink->src) */
 #define IBLND_MSG_GET_DONE          0xd7        /* completion (src->sink: all OK) */
 
+/* flag to show a peer can understand connrace protocol */
+#define IBLND_CONNREQ_NOOP         (1U << 0)
+/* want to win connrace */
+#define IBLND_CONNREQ_WIN_WISH     (1U << 1)
+
 typedef struct {
         __u32            ibr_magic;             /* sender's magic */
         __u16            ibr_version;           /* sender's version */
@@ -652,6 +657,8 @@ typedef struct kib_conn
        __u16                   ibc_version;
        /* reconnect later */
        __u16                   ibc_reconnect:1;
+       /* rejected by connrace */
+       __u16                   ibc_connrace:1;
        /* which instance of the peer */
        __u64                   ibc_incarnation;
        /* # users */
@@ -745,6 +752,8 @@ typedef struct kib_peer
        unsigned short          ibp_connecting;
        /* reconnect this peer later */
        unsigned short          ibp_reconnecting:1;
+       /* wish to win the connrace */
+       unsigned short       ibp_connrace_win:1;
        /* # consecutive reconnection attempts to this peer */
        unsigned int            ibp_reconnected;
        /* errno on closing this peer */
@@ -831,6 +840,25 @@ do {                                                            \
 } while (0)
 
 static inline bool
+kiblnd_peer_win_race(kib_peer_t *peer, kib_msg_t *msg)
+{
+       if (!peer->ibp_connecting)
+               return true; /* no race */
+
+       if (msg->ibm_credits & IBLND_CONNREQ_NOOP) {
+               /* peer can understand connrace protocol */
+
+               if (msg->ibm_credits & IBLND_CONNREQ_WIN_WISH)
+                       return true; /* peer has win wish */
+
+               if (peer->ibp_connrace_win)
+                       return false; /* I wish to win, reject peer */
+       }
+       /* tie-break connection race in favour of the higher NID */
+       return peer->ibp_nid > peer->ibp_ni->ni_nid;
+}
+
+static inline bool
 kiblnd_peer_connecting(kib_peer_t *peer)
 {
        return peer->ibp_connecting != 0 ||
@@ -1120,7 +1148,7 @@ int  kiblnd_translate_mtu(int value);
 int  kiblnd_dev_failover(kib_dev_t *dev);
 int  kiblnd_create_peer(lnet_ni_t *ni, kib_peer_t **peerp, lnet_nid_t nid);
 void kiblnd_destroy_peer (kib_peer_t *peer);
-bool kiblnd_reconnect_peer(kib_peer_t *peer);
+bool kiblnd_reconnect_peer(kib_peer_t *peer, bool connrace_win);
 void kiblnd_destroy_dev (kib_dev_t *dev);
 void kiblnd_unlink_peer_locked (kib_peer_t *peer);
 kib_peer_t *kiblnd_find_peer_locked (lnet_nid_t nid);