[PATCH 26/27] staging: lustre: avoid intensive reconnecting for ko2iblnd

From: James Simmons
Date: Wed Mar 02 2016 - 17:03:10 EST

From: Liang Zhen <liang.zhen@xxxxxxxxx>

When there is a connection race between two nodes and one side
of the connection is rejected by the other side. o2iblnd will
reconnect immediately, this is going to generate a lot of
trashes if:

- race winner is slow and can't send out connecting request
in short time.
- remote side leaves a cmid in TIMEWAIT state, which will reject
future connection requests

To resolve this problem, this patch changed the reconnection
behave: reconnection is submitted by connd only if a zombie
connection is being destroyed and there is a pending
reconnection request for the corresponding peer.

Also, after a few rejections, reconnection will have a time
interval between each attempt.

Signed-off-by: Liang Zhen <liang.zhen@xxxxxxxxx>
Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-7569
Reviewed-on: http://review.whamcloud.com/17892
Reviewed-by: Doug Oucharek <doug.s.oucharek@xxxxxxxxx>
Reviewed-by: James Simmons <uja.ornl@xxxxxxxxx>
Tested-by: James Simmons <uja.ornl@xxxxxxxxx>
Reviewed-by: Oleg Drokin <oleg.drokin@xxxxxxxxx>
---
.../staging/lustre/lnet/klnds/o2iblnd/o2iblnd.c | 40 +--
.../staging/lustre/lnet/klnds/o2iblnd/o2iblnd.h | 54 +++-
.../staging/lustre/lnet/klnds/o2iblnd/o2iblnd_cb.c | 280 ++++++++++++++------
3 files changed, 258 insertions(+), 116 deletions(-)

diff --git a/drivers/staging/lustre/lnet/klnds/o2iblnd/o2iblnd.c b/drivers/staging/lustre/lnet/klnds/o2iblnd/o2iblnd.c
index 56c221b..135ccf1 100644
--- a/drivers/staging/lustre/lnet/klnds/o2iblnd/o2iblnd.c
+++ b/drivers/staging/lustre/lnet/klnds/o2iblnd/o2iblnd.c
@@ -364,9 +364,7 @@ void kiblnd_destroy_peer(kib_peer_t *peer)
LASSERT(net);
LASSERT(!atomic_read(&peer->ibp_refcount));
LASSERT(!kiblnd_peer_active(peer));
- LASSERT(!peer->ibp_connecting);
- LASSERT(!peer->ibp_accepting);
- LASSERT(list_empty(&peer->ibp_conns));
+ LASSERT(kiblnd_peer_idle(peer));
LASSERT(list_empty(&peer->ibp_tx_queue));

LIBCFS_FREE(peer, sizeof(*peer));
@@ -392,10 +390,7 @@ kib_peer_t *kiblnd_find_peer_locked(lnet_nid_t nid)

list_for_each(tmp, peer_list) {
peer = list_entry(tmp, kib_peer_t, ibp_list);
-
- LASSERT(peer->ibp_connecting > 0 || /* creating conns */
- peer->ibp_accepting > 0 ||
- !list_empty(&peer->ibp_conns)); /* active conn */
+ LASSERT(!kiblnd_peer_idle(peer));

if (peer->ibp_nid != nid)
continue;
@@ -432,9 +427,7 @@ static int kiblnd_get_peer_info(lnet_ni_t *ni, int index,
for (i = 0; i < kiblnd_data.kib_peer_hash_size; i++) {
list_for_each(ptmp, &kiblnd_data.kib_peers[i]) {
peer = list_entry(ptmp, kib_peer_t, ibp_list);
- LASSERT(peer->ibp_connecting > 0 ||
- peer->ibp_accepting > 0 ||
- !list_empty(&peer->ibp_conns));
+ LASSERT(!kiblnd_peer_idle(peer));

if (peer->ibp_ni != ni)
continue;
@@ -502,9 +495,7 @@ static int kiblnd_del_peer(lnet_ni_t *ni, lnet_nid_t nid)
for (i = lo; i <= hi; i++) {
list_for_each_safe(ptmp, pnxt, &kiblnd_data.kib_peers[i]) {
peer = list_entry(ptmp, kib_peer_t, ibp_list);
- LASSERT(peer->ibp_connecting > 0 ||
- peer->ibp_accepting > 0 ||
- !list_empty(&peer->ibp_conns));
+ LASSERT(!kiblnd_peer_idle(peer));

if (peer->ibp_ni != ni)
continue;
@@ -545,9 +536,7 @@ static kib_conn_t *kiblnd_get_conn_by_idx(lnet_ni_t *ni, int index)
for (i = 0; i < kiblnd_data.kib_peer_hash_size; i++) {
list_for_each(ptmp, &kiblnd_data.kib_peers[i]) {
peer = list_entry(ptmp, kib_peer_t, ibp_list);
- LASSERT(peer->ibp_connecting > 0 ||
- peer->ibp_accepting > 0 ||
- !list_empty(&peer->ibp_conns));
+ LASSERT(!kiblnd_peer_idle(peer));

if (peer->ibp_ni != ni)
continue;
@@ -837,14 +826,14 @@ kib_conn_t *kiblnd_create_conn(kib_peer_t *peer, struct rdma_cm_id *cmid,
return conn;

failed_2:
- kiblnd_destroy_conn(conn);
+ kiblnd_destroy_conn(conn, true);
failed_1:
LIBCFS_FREE(init_qp_attr, sizeof(*init_qp_attr));
failed_0:
return NULL;
}

-void kiblnd_destroy_conn(kib_conn_t *conn)
+void kiblnd_destroy_conn(kib_conn_t *conn, bool free_conn)
{
struct rdma_cm_id *cmid = conn->ibc_cmid;
kib_peer_t *peer = conn->ibc_peer;
@@ -984,9 +973,7 @@ static int kiblnd_close_matching_conns(lnet_ni_t *ni, lnet_nid_t nid)
for (i = lo; i <= hi; i++) {
list_for_each_safe(ptmp, pnxt, &kiblnd_data.kib_peers[i]) {
peer = list_entry(ptmp, kib_peer_t, ibp_list);
- LASSERT(peer->ibp_connecting > 0 ||
- peer->ibp_accepting > 0 ||
- !list_empty(&peer->ibp_conns));
+ LASSERT(!kiblnd_peer_idle(peer));

if (peer->ibp_ni != ni)
continue;
@@ -1071,12 +1058,8 @@ static void kiblnd_query(lnet_ni_t *ni, lnet_nid_t nid, unsigned long *when)
read_lock_irqsave(glock, flags);

peer = kiblnd_find_peer_locked(nid);
- if (peer) {
- LASSERT(peer->ibp_connecting > 0 || /* creating conns */
- peer->ibp_accepting > 0 ||
- !list_empty(&peer->ibp_conns)); /* active conn */
+ if (peer)
last_alive = peer->ibp_last_alive;
- }

read_unlock_irqrestore(glock, flags);

@@ -2368,6 +2351,8 @@ static void kiblnd_base_shutdown(void)
LASSERT(list_empty(&kiblnd_data.kib_peers[i]));
LASSERT(list_empty(&kiblnd_data.kib_connd_zombies));
LASSERT(list_empty(&kiblnd_data.kib_connd_conns));
+ LASSERT(list_empty(&kiblnd_data.kib_reconn_list));
+ LASSERT(list_empty(&kiblnd_data.kib_reconn_wait));

/* flag threads to terminate; wake and wait for them to die */
kiblnd_data.kib_shutdown = 1;
@@ -2506,6 +2491,9 @@ static int kiblnd_base_startup(void)
spin_lock_init(&kiblnd_data.kib_connd_lock);
INIT_LIST_HEAD(&kiblnd_data.kib_connd_conns);
INIT_LIST_HEAD(&kiblnd_data.kib_connd_zombies);
+ INIT_LIST_HEAD(&kiblnd_data.kib_reconn_list);
+ INIT_LIST_HEAD(&kiblnd_data.kib_reconn_wait);
+
init_waitqueue_head(&kiblnd_data.kib_connd_waitq);
init_waitqueue_head(&kiblnd_data.kib_failover_waitq);

diff --git a/drivers/staging/lustre/lnet/klnds/o2iblnd/o2iblnd.h b/drivers/staging/lustre/lnet/klnds/o2iblnd/o2iblnd.h
index 6a4c4ac..bfcbdd1 100644
--- a/drivers/staging/lustre/lnet/klnds/o2iblnd/o2iblnd.h
+++ b/drivers/staging/lustre/lnet/klnds/o2iblnd/o2iblnd.h
@@ -348,6 +348,16 @@ typedef struct {
void *kib_connd; /* the connd task (serialisation assertions) */
struct list_head kib_connd_conns; /* connections to setup/teardown */
struct list_head kib_connd_zombies; /* connections with zero refcount */
+ /* connections to reconnect */
+ struct list_head kib_reconn_list;
+ /* peers wait for reconnection */
+ struct list_head kib_reconn_wait;
+ /**
+ * The second that peers are pulled out from \a kib_reconn_wait
+ * for reconnection.
+ */
+ time64_t kib_reconn_sec;
+
wait_queue_head_t kib_connd_waitq; /* connection daemon sleeps here */
spinlock_t kib_connd_lock; /* serialise */
struct ib_qp_attr kib_error_qpa; /* QP->ERROR */
@@ -525,6 +535,8 @@ typedef struct kib_conn {
struct list_head ibc_list; /* stash on peer's conn list */
struct list_head ibc_sched_list; /* schedule for attention */
__u16 ibc_version; /* version of connection */
+ /* reconnect later */
+ __u16 ibc_reconnect:1;
__u64 ibc_incarnation; /* which instance of the peer */
atomic_t ibc_refcount; /* # users */
int ibc_state; /* what's happening */
@@ -574,18 +586,25 @@ typedef struct kib_peer {
struct list_head ibp_list; /* stash on global peer list */
lnet_nid_t ibp_nid; /* who's on the other end(s) */
lnet_ni_t *ibp_ni; /* LNet interface */
- atomic_t ibp_refcount; /* # users */
struct list_head ibp_conns; /* all active connections */
struct list_head ibp_tx_queue; /* msgs waiting for a conn */
- __u16 ibp_version; /* version of peer */
__u64 ibp_incarnation; /* incarnation of peer */
- int ibp_connecting; /* current active connection attempts
- */
- int ibp_accepting; /* current passive connection attempts
- */
- int ibp_error; /* errno on closing this peer */
- unsigned long ibp_last_alive; /* when (in jiffies) I was last alive
- */
+ /* when (in jiffies) I was last alive */
+ unsigned long ibp_last_alive;
+ /* # users */
+ atomic_t ibp_refcount;
+ /* version of peer */
+ __u16 ibp_version;
+ /* current passive connection attempts */
+ unsigned short ibp_accepting;
+ /* current active connection attempts */
+ unsigned short ibp_connecting;
+ /* reconnect this peer later */
+ unsigned short ibp_reconnecting:1;
+ /* # consecutive reconnection attempts to this peer */
+ unsigned int ibp_reconnected;
+ /* errno on closing this peer */
+ int ibp_error;
/* max map_on_demand */
__u16 ibp_max_frags;
/* max_peer_credits */
@@ -667,6 +686,20 @@ do { \
kiblnd_destroy_peer(peer); \
} while (0)

+static inline bool
+kiblnd_peer_connecting(kib_peer_t *peer)
+{
+ return peer->ibp_connecting ||
+ peer->ibp_reconnecting ||
+ peer->ibp_accepting;
+}
+
+static inline bool
+kiblnd_peer_idle(kib_peer_t *peer)
+{
+ return !kiblnd_peer_connecting(peer) && list_empty(&peer->ibp_conns);
+}
+
static inline struct list_head *
kiblnd_nid2peerlist(lnet_nid_t nid)
{
@@ -943,6 +976,7 @@ 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);
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);
@@ -952,7 +986,7 @@ int kiblnd_close_peer_conns_locked(kib_peer_t *peer, int why);

kib_conn_t *kiblnd_create_conn(kib_peer_t *peer, struct rdma_cm_id *cmid,
int state, int version);
-void kiblnd_destroy_conn(kib_conn_t *conn);
+void kiblnd_destroy_conn(kib_conn_t *conn, bool free_conn);
void kiblnd_close_conn(kib_conn_t *conn, int error);
void kiblnd_close_conn_locked(kib_conn_t *conn, int error);

diff --git a/drivers/staging/lustre/lnet/klnds/o2iblnd/o2iblnd_cb.c b/drivers/staging/lustre/lnet/klnds/o2iblnd/o2iblnd_cb.c
index 1c62875..9e7efc8 100644
--- a/drivers/staging/lustre/lnet/klnds/o2iblnd/o2iblnd_cb.c
+++ b/drivers/staging/lustre/lnet/klnds/o2iblnd/o2iblnd_cb.c
@@ -1258,6 +1258,7 @@ kiblnd_connect_peer(kib_peer_t *peer)

LASSERT(net);
LASSERT(peer->ibp_connecting > 0);
+ LASSERT(!peer->ibp_reconnecting);

cmid = kiblnd_rdma_create_id(kiblnd_cm_callback, peer, RDMA_PS_TCP,
IB_QPT_RC);
@@ -1313,6 +1314,56 @@ kiblnd_connect_peer(kib_peer_t *peer)
kiblnd_peer_connect_failed(peer, 1, rc);
}

+bool
+kiblnd_reconnect_peer(kib_peer_t *peer)
+{
+ rwlock_t *glock = &kiblnd_data.kib_global_lock;
+ char *reason = NULL;
+ struct list_head txs;
+ unsigned long flags;
+
+ INIT_LIST_HEAD(&txs);
+
+ write_lock_irqsave(glock, flags);
+ if (!peer->ibp_reconnecting) {
+ if (peer->ibp_accepting)
+ reason = "accepting";
+ else if (peer->ibp_connecting)
+ reason = "connecting";
+ else if (!list_empty(&peer->ibp_conns))
+ reason = "connected";
+ else /* connected then closed */
+ reason = "closed";
+
+ goto no_reconnect;
+ }
+
+ LASSERT(!peer->ibp_accepting && !peer->ibp_connecting &&
+ list_empty(&peer->ibp_conns));
+ peer->ibp_reconnecting = 0;
+
+ if (!kiblnd_peer_active(peer)) {
+ list_splice_init(&peer->ibp_tx_queue, &txs);
+ reason = "unlinked";
+ goto no_reconnect;
+ }
+
+ peer->ibp_connecting++;
+ peer->ibp_reconnected++;
+ write_unlock_irqrestore(glock, flags);
+
+ kiblnd_connect_peer(peer);
+ return true;
+
+no_reconnect:
+ write_unlock_irqrestore(glock, flags);
+
+ CWARN("Abort reconnection of %s: %s\n",
+ libcfs_nid2str(peer->ibp_nid), reason);
+ kiblnd_txlist_done(peer->ibp_ni, &txs, -ECONNABORTED);
+ return false;
+}
+
void
kiblnd_launch_tx(lnet_ni_t *ni, kib_tx_t *tx, lnet_nid_t nid)
{
@@ -1358,8 +1409,7 @@ kiblnd_launch_tx(lnet_ni_t *ni, kib_tx_t *tx, lnet_nid_t nid)
if (peer) {
if (list_empty(&peer->ibp_conns)) {
/* found a peer, but it's still connecting... */
- LASSERT(peer->ibp_connecting ||
- peer->ibp_accepting);
+ LASSERT(kiblnd_peer_connecting(peer));
if (tx)
list_add_tail(&tx->tx_list,
&peer->ibp_tx_queue);
@@ -1397,8 +1447,7 @@ kiblnd_launch_tx(lnet_ni_t *ni, kib_tx_t *tx, lnet_nid_t nid)
if (peer2) {
if (list_empty(&peer2->ibp_conns)) {
/* found a peer, but it's still connecting... */
- LASSERT(peer2->ibp_connecting ||
- peer2->ibp_accepting);
+ LASSERT(kiblnd_peer_connecting(peer2));
if (tx)
list_add_tail(&tx->tx_list,
&peer2->ibp_tx_queue);
@@ -1818,10 +1867,7 @@ kiblnd_peer_notify(kib_peer_t *peer)

read_lock_irqsave(&kiblnd_data.kib_global_lock, flags);

- if (list_empty(&peer->ibp_conns) &&
- !peer->ibp_accepting &&
- !peer->ibp_connecting &&
- peer->ibp_error) {
+ if (kiblnd_peer_idle(peer) && peer->ibp_error) {
error = peer->ibp_error;
peer->ibp_error = 0;

@@ -2021,14 +2067,14 @@ kiblnd_peer_connect_failed(kib_peer_t *peer, int active, int error)
peer->ibp_accepting--;
}

- if (peer->ibp_connecting ||
- peer->ibp_accepting) {
+ if (kiblnd_peer_connecting(peer)) {
/* another connection attempt under way... */
write_unlock_irqrestore(&kiblnd_data.kib_global_lock,
flags);
return;
}

+ peer->ibp_reconnected = 0;
if (list_empty(&peer->ibp_conns)) {
/* Take peer's blocked transmits to complete with error */
list_add(&zombies, &peer->ibp_tx_queue);
@@ -2101,6 +2147,7 @@ kiblnd_connreq_done(kib_conn_t *conn, int status)
*/
kiblnd_conn_addref(conn); /* +1 ref for ibc_list */
list_add(&conn->ibc_list, &peer->ibp_conns);
+ peer->ibp_reconnected = 0;
if (active)
peer->ibp_connecting--;
else
@@ -2356,10 +2403,16 @@ kiblnd_passive_connect(struct rdma_cm_id *cmid, void *priv, int priv_nob)
if (peer2->ibp_incarnation != reqmsg->ibm_srcstamp ||
peer2->ibp_version != version) {
kiblnd_close_peer_conns_locked(peer2, -ESTALE);
+
+ if (kiblnd_peer_active(peer2)) {
+ peer2->ibp_incarnation = reqmsg->ibm_srcstamp;
+ peer2->ibp_version = version;
+ }
write_unlock_irqrestore(g_lock, flags);

- CWARN("Conn stale %s [old ver: %x, new ver: %x]\n",
- libcfs_nid2str(nid), peer2->ibp_version, version);
+ CWARN("Conn stale %s version %x/%x incarnation %llu/%llu\n",
+ libcfs_nid2str(nid), peer2->ibp_version, version,
+ peer2->ibp_incarnation, reqmsg->ibm_srcstamp);

kiblnd_peer_decref(peer);
rej.ibr_why = IBLND_REJECT_CONN_STALE;
@@ -2378,6 +2431,11 @@ kiblnd_passive_connect(struct rdma_cm_id *cmid, void *priv, int priv_nob)
goto failed;
}

+ /**
+ * passive connection is allowed even this peer is waiting for
+ * reconnection.
+ */
+ peer2->ibp_reconnecting = 0;
peer2->ibp_accepting++;
kiblnd_peer_addref(peer2);

@@ -2479,75 +2537,79 @@ kiblnd_passive_connect(struct rdma_cm_id *cmid, void *priv, int priv_nob)
}

static void
-kiblnd_reconnect(kib_conn_t *conn, int version,
- __u64 incarnation, int why, kib_connparams_t *cp)
+kiblnd_check_reconnect(kib_conn_t *conn, int version,
+ __u64 incarnation, int why, kib_connparams_t *cp)
{
+ rwlock_t *glock = &kiblnd_data.kib_global_lock;
kib_peer_t *peer = conn->ibc_peer;
char *reason;
- int retry = 0;
+ int msg_size = IBLND_MSG_SIZE;
+ int frag_num = -1;
+ int queue_dep = -1;
+ bool reconnect;
unsigned long flags;

LASSERT(conn->ibc_state == IBLND_CONN_ACTIVE_CONNECT);
LASSERT(peer->ibp_connecting > 0); /* 'conn' at least */
+ LASSERT(!peer->ibp_reconnecting);

- write_lock_irqsave(&kiblnd_data.kib_global_lock, flags);
+ if (cp) {
+ msg_size = cp->ibcp_max_msg_size;
+ frag_num = cp->ibcp_max_frags;
+ queue_dep = cp->ibcp_queue_depth;
+ }

- /*
+ write_lock_irqsave(glock, flags);
+ /**
* retry connection if it's still needed and no other connection
* attempts (active or passive) are in progress
* NB: reconnect is still needed even when ibp_tx_queue is
* empty if ibp_version != version because reconnect may be
* initiated by kiblnd_query()
*/
- if ((!list_empty(&peer->ibp_tx_queue) ||
- peer->ibp_version != version) &&
- peer->ibp_connecting == 1 &&
- !peer->ibp_accepting) {
- retry = 1;
- peer->ibp_connecting++;
-
- peer->ibp_version = version;
- peer->ibp_incarnation = incarnation;
+ reconnect = (!list_empty(&peer->ibp_tx_queue) ||
+ peer->ibp_version != version) &&
+ peer->ibp_connecting == 1 &&
+ !peer->ibp_accepting;
+ if (!reconnect) {
+ reason = "no need";
+ goto out;
}

- write_unlock_irqrestore(&kiblnd_data.kib_global_lock, flags);
-
- if (!retry)
- return;
-
switch (why) {
default:
reason = "Unknown";
break;

case IBLND_REJECT_RDMA_FRAGS:
- if (!cp)
- goto failed;
-
- if (conn->ibc_max_frags <= cp->ibcp_max_frags) {
- CNETERR("Unsupported max frags, peer supports %d\n",
- cp->ibcp_max_frags);
- goto failed;
- } else if (!*kiblnd_tunables.kib_map_on_demand) {
- CNETERR("map_on_demand must be enabled to support map_on_demand peers\n");
- goto failed;
+ if (!cp) {
+ reason = "can't negotiate max frags";
+ goto out;
+ }
+ if (!*kiblnd_tunables.kib_map_on_demand) {
+ reason = "map_on_demand must be enabled";
+ goto out;
+ }
+ if (conn->ibc_max_frags <= frag_num) {
+ reason = "unsupported max frags";
+ goto out;
}

- peer->ibp_max_frags = cp->ibcp_max_frags;
+ peer->ibp_max_frags = frag_num;
reason = "rdma fragments";
break;

case IBLND_REJECT_MSG_QUEUE_SIZE:
- if (!cp)
- goto failed;
-
- if (conn->ibc_queue_depth <= cp->ibcp_queue_depth) {
- CNETERR("Unsupported queue depth, peer supports %d\n",
- cp->ibcp_queue_depth);
- goto failed;
+ if (!cp) {
+ reason = "can't negotiate queue depth";
+ goto out;
+ }
+ if (conn->ibc_queue_depth <= queue_dep) {
+ reason = "unsupported queue depth";
+ goto out;
}

- peer->ibp_queue_depth = cp->ibcp_queue_depth;
+ peer->ibp_queue_depth = queue_dep;
reason = "queue depth";
break;

@@ -2564,20 +2626,24 @@ kiblnd_reconnect(kib_conn_t *conn, int version,
break;
}

- CNETERR("%s: retrying (%s), %x, %x, queue_dep: %d, max_frag: %d, msg_size: %d\n",
- libcfs_nid2str(peer->ibp_nid),
- reason, IBLND_MSG_VERSION, version,
- conn->ibc_queue_depth, conn->ibc_max_frags,
- cp ? cp->ibcp_max_msg_size : IBLND_MSG_SIZE);
-
- kiblnd_connect_peer(peer);
- return;
-failed:
- write_lock_irqsave(&kiblnd_data.kib_global_lock, flags);
- peer->ibp_connecting--;
- write_unlock_irqrestore(&kiblnd_data.kib_global_lock, flags);
+ conn->ibc_reconnect = 1;
+ peer->ibp_reconnecting = 1;
+ peer->ibp_version = version;
+ if (incarnation)
+ peer->ibp_incarnation = incarnation;
+out:
+ write_unlock_irqrestore(glock, flags);

- return;
+ CNETERR("%s: %s (%s), %x, %x, msg_size: %d, queue_depth: %d/%d, max_frags: %d/%d\n",
+ libcfs_nid2str(peer->ibp_nid),
+ reconnect ? "reconnect" : "don't reconnect",
+ reason, IBLND_MSG_VERSION, version, msg_size,
+ conn->ibc_queue_depth, queue_dep,
+ conn->ibc_max_frags, frag_num);
+ /**
+ * if conn::ibc_reconnect is TRUE, connd will reconnect to the peer
+ * while destroying the zombie
+ */
}

static void
@@ -2590,8 +2656,8 @@ kiblnd_rejected(kib_conn_t *conn, int reason, void *priv, int priv_nob)

switch (reason) {
case IB_CM_REJ_STALE_CONN:
- kiblnd_reconnect(conn, IBLND_MSG_VERSION, 0,
- IBLND_REJECT_CONN_STALE, NULL);
+ kiblnd_check_reconnect(conn, IBLND_MSG_VERSION, 0,
+ IBLND_REJECT_CONN_STALE, NULL);
break;

case IB_CM_REJ_INVALID_SERVICE_ID:
@@ -2675,8 +2741,9 @@ kiblnd_rejected(kib_conn_t *conn, int reason, void *priv, int priv_nob)
case IBLND_REJECT_CONN_UNCOMPAT:
case IBLND_REJECT_MSG_QUEUE_SIZE:
case IBLND_REJECT_RDMA_FRAGS:
- kiblnd_reconnect(conn, rej->ibr_version,
- incarnation, rej->ibr_why, cp);
+ kiblnd_check_reconnect(conn, rej->ibr_version,
+ incarnation,
+ rej->ibr_why, cp);
break;

case IBLND_REJECT_NO_RESOURCES:
@@ -3180,9 +3247,21 @@ kiblnd_disconnect_conn(kib_conn_t *conn)
kiblnd_peer_notify(conn->ibc_peer);
}

+/**
+ * High-water for reconnection to the same peer, reconnection attempt should
+ * be delayed after trying more than KIB_RECONN_HIGH_RACE.
+ */
+#define KIB_RECONN_HIGH_RACE 10
+/**
+ * Allow connd to take a break and handle other things after consecutive
+ * reconnection attemps.
+ */
+#define KIB_RECONN_BREAK 100
+
int
kiblnd_connd(void *arg)
{
+ spinlock_t *lock= &kiblnd_data.kib_connd_lock;
wait_queue_t wait;
unsigned long flags;
kib_conn_t *conn;
@@ -3197,23 +3276,40 @@ kiblnd_connd(void *arg)
init_waitqueue_entry(&wait, current);
kiblnd_data.kib_connd = current;

- spin_lock_irqsave(&kiblnd_data.kib_connd_lock, flags);
+ spin_lock_irqsave(lock, flags);

while (!kiblnd_data.kib_shutdown) {
+ int reconn = 0;
+
dropped_lock = 0;

if (!list_empty(&kiblnd_data.kib_connd_zombies)) {
+ kib_peer_t *peer = NULL;
+
conn = list_entry(kiblnd_data.kib_connd_zombies.next,
kib_conn_t, ibc_list);
list_del(&conn->ibc_list);
+ if (conn->ibc_reconnect) {
+ peer = conn->ibc_peer;
+ kiblnd_peer_addref(peer);
+ }

- spin_unlock_irqrestore(&kiblnd_data.kib_connd_lock,
- flags);
+ spin_unlock_irqrestore(lock, flags);
dropped_lock = 1;

- kiblnd_destroy_conn(conn);
+ kiblnd_destroy_conn(conn, !peer);

- spin_lock_irqsave(&kiblnd_data.kib_connd_lock, flags);
+ spin_lock_irqsave(lock, flags);
+ if (!peer)
+ continue;
+
+ conn->ibc_peer = peer;
+ if (peer->ibp_reconnected < KIB_RECONN_HIGH_RACE)
+ list_add_tail(&conn->ibc_list,
+ &kiblnd_data.kib_reconn_list);
+ else
+ list_add_tail(&conn->ibc_list,
+ &kiblnd_data.kib_reconn_wait);
}

if (!list_empty(&kiblnd_data.kib_connd_conns)) {
@@ -3221,14 +3317,38 @@ kiblnd_connd(void *arg)
kib_conn_t, ibc_list);
list_del(&conn->ibc_list);

- spin_unlock_irqrestore(&kiblnd_data.kib_connd_lock,
- flags);
+ spin_unlock_irqrestore(lock, flags);
dropped_lock = 1;

kiblnd_disconnect_conn(conn);
kiblnd_conn_decref(conn);

- spin_lock_irqsave(&kiblnd_data.kib_connd_lock, flags);
+ spin_lock_irqsave(lock, flags);
+ }
+
+ while (reconn < KIB_RECONN_BREAK) {
+ if (kiblnd_data.kib_reconn_sec !=
+ ktime_get_real_seconds()) {
+ kiblnd_data.kib_reconn_sec = ktime_get_real_seconds();
+ list_splice_init(&kiblnd_data.kib_reconn_wait,
+ &kiblnd_data.kib_reconn_list);
+ }
+
+ if (list_empty(&kiblnd_data.kib_reconn_list))
+ break;
+
+ conn = list_entry(kiblnd_data.kib_reconn_list.next,
+ kib_conn_t, ibc_list);
+ list_del(&conn->ibc_list);
+
+ spin_unlock_irqrestore(lock, flags);
+ dropped_lock = 1;
+
+ reconn += kiblnd_reconnect_peer(conn->ibc_peer);
+ kiblnd_peer_decref(conn->ibc_peer);
+ LIBCFS_FREE(conn, sizeof(*conn));
+
+ spin_lock_irqsave(lock, flags);
}

/* careful with the jiffy wrap... */
@@ -3238,7 +3358,7 @@ kiblnd_connd(void *arg)
const int p = 1;
int chunk = kiblnd_data.kib_peer_hash_size;

- spin_unlock_irqrestore(&kiblnd_data.kib_connd_lock, flags);
+ spin_unlock_irqrestore(lock, flags);
dropped_lock = 1;

/*
@@ -3263,7 +3383,7 @@ kiblnd_connd(void *arg)
}

deadline += msecs_to_jiffies(p * MSEC_PER_SEC);
- spin_lock_irqsave(&kiblnd_data.kib_connd_lock, flags);
+ spin_lock_irqsave(lock, flags);
}

if (dropped_lock)
@@ -3272,15 +3392,15 @@ kiblnd_connd(void *arg)
/* Nothing to do for 'timeout' */
set_current_state(TASK_INTERRUPTIBLE);
add_wait_queue(&kiblnd_data.kib_connd_waitq, &wait);
- spin_unlock_irqrestore(&kiblnd_data.kib_connd_lock, flags);
+ spin_unlock_irqrestore(lock, flags);

schedule_timeout(timeout);

remove_wait_queue(&kiblnd_data.kib_connd_waitq, &wait);
- spin_lock_irqsave(&kiblnd_data.kib_connd_lock, flags);
+ spin_lock_irqsave(lock, flags);
}

- spin_unlock_irqrestore(&kiblnd_data.kib_connd_lock, flags);
+ spin_unlock_irqrestore(lock, flags);

kiblnd_thread_fini();
return 0;
--
1.7.1