static int
lnet_select_pathway(lnet_nid_t src_nid, lnet_nid_t dst_nid,
- struct lnet_msg *msg, lnet_nid_t rtr_nid, bool *lo_sent)
+ struct lnet_msg *msg, lnet_nid_t rtr_nid)
{
- struct lnet_ni *best_ni = NULL;
- struct lnet_peer_ni *best_lpni = NULL;
- struct lnet_peer_ni *net_gw = NULL;
- struct lnet_peer_ni *best_gw = NULL;
+ struct lnet_ni *best_ni;
+ struct lnet_peer_ni *best_lpni;
+ struct lnet_peer_ni *best_gw;
struct lnet_peer_ni *lpni;
- struct lnet_peer *peer = NULL;
+ struct lnet_peer *peer;
struct lnet_peer_net *peer_net;
struct lnet_net *local_net;
- struct lnet_ni *ni = NULL;
+ struct lnet_ni *ni;
+ __u32 seq;
int cpt, cpt2, rc;
- bool routing = false;
- bool ni_is_pref = false;
- bool preferred = false;
- int best_credits = 0;
- __u32 seq, seq2;
- int best_lpni_credits = INT_MIN;
- int md_cpt = 0;
- int shortest_distance = INT_MAX;
- int distance = 0;
- bool found_ir = false;
+ bool routing;
+ bool ni_is_pref;
+ bool preferred;
+ int best_credits;
+ int best_lpni_credits;
+ int md_cpt;
+ int shortest_distance;
-again:
/*
* get an initial CPT to use for locking. The idea here is not to
* serialize the calls to select_pathway, so that as many
* operations can run concurrently as possible. To do that we use
* the CPT where this call is being executed. Later on when we
* determine the CPT to use in lnet_message_commit, we switch the
- * lock and check if there was any configuration changes, if none,
- * then we proceed, if there is, then we'll need to update the cpt
- * and redo the operation.
+ * lock and check if there was any configuration change. If none,
+ * then we proceed, if there is, then we restart the operation.
*/
cpt = lnet_net_lock_current();
-
+again:
+ best_ni = NULL;
+ best_lpni = NULL;
best_gw = NULL;
- routing = false;
local_net = NULL;
- best_ni = NULL;
- shortest_distance = INT_MAX;
- found_ir = false;
+ routing = false;
+
+ seq = lnet_get_dlc_seq_locked();
if (the_lnet.ln_shutdown) {
lnet_net_unlock(cpt);
else
md_cpt = CFS_CPT_ANY;
- /*
- * initialize the variables which could be reused if we go to
- * again
- */
- lpni = NULL;
- seq = lnet_get_dlc_seq_locked();
-
peer = lnet_find_or_create_peer_locked(dst_nid, cpt);
if (IS_ERR(peer)) {
lnet_net_unlock(cpt);
libcfs_nid2str(src_nid));
return -EINVAL;
}
- }
-
- if (best_ni)
goto pick_peer;
+ }
/*
* Decide whether we need to route to peer_ni.
local_net = lnet_get_net_locked(peer_net->lpn_net_id);
if (!local_net) {
+ struct lnet_peer_ni *net_gw;
/*
* go through each peer_ni on that peer_net and
* determine the best possible gw to go through
* 2. NI available credits
* 3. Round Robin
*/
+ shortest_distance = INT_MAX;
+ best_credits = INT_MIN;
+ ni = NULL;
while ((ni = lnet_get_next_ni_locked(local_net, ni))) {
int ni_credits;
+ int distance;
if (!lnet_is_ni_healthy_locked(ni))
continue;
ni_credits = atomic_read(&ni->ni_tx_credits);
/*
- * calculate the distance from the cpt on which
+ * calculate the distance from the CPT on which
* the message memory is allocated to the CPT of
* the NI's physical device
*/
ni->dev_cpt);
/*
- * If we already have a closer NI within the NUMA
- * range provided, then there is no need to
- * consider the current NI. Move on to the next
- * one.
+ * All distances smaller than the NUMA range
+ * are treated equally.
*/
- if (distance > shortest_distance &&
- distance > lnet_get_numa_range())
- continue;
+ if (distance < lnet_get_numa_range())
+ distance = lnet_get_numa_range();
- if (distance < shortest_distance &&
- distance > lnet_get_numa_range()) {
- /*
- * The current NI is the closest one that we
- * have found, even though it's not in the
- * NUMA range specified. This occurs if
- * the NUMA range is less than the least
- * of the distances in the system.
- * In effect NUMA range consideration is
- * turned off.
- */
+ /*
+ * Select on shorter distance, then available
+ * credits, then round-robin.
+ */
+ if (distance > shortest_distance) {
+ continue;
+ } else if (distance < shortest_distance) {
shortest_distance = distance;
- } else if ((distance <= shortest_distance &&
- distance < lnet_get_numa_range()) ||
- distance == shortest_distance) {
- /*
- * This NI is either within range or it's
- * equidistant. In both of these cases we
- * would want to select the NI based on
- * its available credits first, and then
- * via Round Robin.
- */
- if (distance <= shortest_distance &&
- distance < lnet_get_numa_range()) {
- /*
- * If this is the first NI that's
- * within range, then set the
- * shortest distance to the range
- * specified by the user. In
- * effect we're saying that all
- * NIs that fall within this NUMA
- * range shall be dealt with as
- * having equal NUMA weight. Which
- * will mean that we should select
- * through that set by their
- * available credits first
- * followed by Round Robin.
- *
- * And since this is the first NI
- * in the range, let's just set it
- * as our best_ni for now. The
- * following NIs found in the
- * range will be dealt with as
- * mentioned previously.
- */
- shortest_distance = lnet_get_numa_range();
- if (!found_ir) {
- found_ir = true;
- goto set_ni;
- }
- }
- /*
- * This NI is NUMA equidistant let's
- * select using credits followed by Round
- * Robin.
- */
- if (ni_credits < best_credits) {
+ } else if (ni_credits < best_credits) {
+ continue;
+ } else if (ni_credits == best_credits) {
+ if (best_ni && best_ni->ni_seq <= ni->ni_seq)
continue;
- } else if (ni_credits == best_credits) {
- if (best_ni) {
- if (best_ni->ni_seq <= ni->ni_seq)
- continue;
- }
- }
}
-set_ni:
best_ni = ni;
best_credits = ni_credits;
}
}
+
/*
* if the peer is not MR capable, then we should always send to it
* using the first NI in the NET we determined.
msg->msg_hdr.src_nid = cpu_to_le64(best_ni->ni_nid);
msg->msg_target.nid = best_ni->ni_nid;
lnet_msg_commit(msg, cpt);
-
- lnet_net_unlock(cpt);
msg->msg_txni = best_ni;
- lnet_ni_send(best_ni, msg);
+ lnet_net_unlock(cpt);
- *lo_sent = true;
- return 0;
+ return LNET_CREDIT_OK;
}
- lpni = NULL;
-
if (msg->msg_type == LNET_MSG_REPLY ||
msg->msg_type == LNET_MSG_ACK) {
/*
* to find another peer_net that we can use
*/
__u32 net_id = peer_net->lpn_net_id;
- lnet_net_unlock(cpt);
- if (!best_lpni)
- LCONSOLE_WARN("peer net %s unhealthy\n",
- libcfs_net2str(net_id));
+ LCONSOLE_WARN("peer net %s unhealthy\n",
+ libcfs_net2str(net_id));
goto again;
}
- best_lpni = NULL;
+ /*
+ * Look at the peer NIs for the destination peer that connect
+ * to the chosen net. If a peer_ni is preferred when using the
+ * best_ni to communicate, we use that one. If there is no
+ * preferred peer_ni, or there are multiple preferred peer_ni,
+ * the available transmit credits are used. If the transmit
+ * credits are equal, we round-robin over the peer_ni.
+ */
+ lpni = NULL;
+ best_lpni_credits = INT_MIN;
+ preferred = false;
while ((lpni = lnet_get_next_peer_ni_locked(peer, peer_net, lpni))) {
/*
* if this peer ni is not healthy just skip it, no point in
best_lpni_credits = lpni->lpni_txcredits;
}
- /*
- * Increment sequence number of the peer selected so that we can
- * pick the next one in Round Robin.
- */
- best_lpni->lpni_seq++;
-
/* if we still can't find a peer ni then we can't reach it */
if (!best_lpni) {
__u32 net_id = peer_net->lpn_net_id;
send:
/*
+ * Increment sequence number of the peer selected so that we
+ * pick the next one in Round Robin.
+ */
+ best_lpni->lpni_seq++;
+
+ /*
+ * When routing the best gateway found acts as the best peer
+ * NI to send to.
+ */
+ if (routing)
+ best_lpni = best_gw;
+
+ /*
+ * grab a reference on the peer_ni so it sticks around even if
+ * we need to drop and relock the lnet_net_lock below.
+ */
+ lnet_peer_ni_addref_locked(best_lpni);
+
+ /*
* Use lnet_cpt_of_nid() to determine the CPT used to commit the
* message. This ensures that we get a CPT that is correct for
* the NI when the NI has been restricted to a subset of all CPTs.
* If the selected CPT differs from the one currently locked, we
* must unlock and relock the lnet_net_lock(), and then check whether
* the configuration has changed. We don't have a hold on the best_ni
- * or best_peer_ni yet, and they may have vanished.
+ * yet, and it may have vanished.
*/
cpt2 = lnet_cpt_of_nid_locked(best_lpni->lpni_nid, best_ni);
if (cpt != cpt2) {
lnet_net_unlock(cpt);
cpt = cpt2;
lnet_net_lock(cpt);
- seq2 = lnet_get_dlc_seq_locked();
- if (seq2 != seq) {
- lnet_net_unlock(cpt);
+ if (seq != lnet_get_dlc_seq_locked()) {
+ lnet_peer_ni_decref_locked(best_lpni);
goto again;
}
}
* store the best_lpni in the message right away to avoid having
* to do the same operation under different conditions
*/
- msg->msg_txpeer = (routing) ? best_gw : best_lpni;
+ msg->msg_txpeer = best_lpni;
msg->msg_txni = best_ni;
+
/*
* grab a reference for the best_ni since now it's in use in this
* send. the reference will need to be dropped when the message is
* finished in lnet_finalize()
*/
lnet_ni_addref_locked(msg->msg_txni, cpt);
- lnet_peer_ni_addref_locked(msg->msg_txpeer);
/*
* set the destination nid in the message here because it's
{
lnet_nid_t dst_nid = msg->msg_target.nid;
int rc;
- bool lo_sent = false;
/*
* NB: rtr_nid is set to LNET_NID_ANY for all current use-cases,
LASSERT(!msg->msg_tx_committed);
- rc = lnet_select_pathway(src_nid, dst_nid, msg, rtr_nid, &lo_sent);
- if (rc < 0 || lo_sent)
+ rc = lnet_select_pathway(src_nid, dst_nid, msg, rtr_nid);
+ if (rc < 0)
return rc;
if (rc == LNET_CREDIT_OK)
git://git.whamcloud.com / fs / lustre-release.git / commitdiff