bond: Fix comment on bond_entry::tag

[sliver-openvswitch.git] / lib / bond.c

diff --git a/lib/bond.c b/lib/bond.c
index 77812ed..c05e0c8 100644 (file)
--- a/lib/bond.c
+++ b/lib/bond.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2008, 2009, 2010, 2011, 2012 Nicira, Inc.
+ * Copyright (c) 2008, 2009, 2010, 2011, 2012, 2013 Nicira, Inc.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -21,6 +21,7 @@
 #include <limits.h>
 #include <stdint.h>
 #include <stdlib.h>
+#include <math.h>
 
 #include "coverage.h"
 #include "dynamic-string.h"
@@ -50,7 +51,7 @@ VLOG_DEFINE_THIS_MODULE(bond);
 struct bond_entry {
     struct bond_slave *slave;   /* Assigned slave, NULL if unassigned. */
     uint64_t tx_bytes;          /* Count of bytes recently transmitted. */
-    tag_type tag;               /* Tag for entry<->slave association. */
+    tag_type tag;               /* Tag for entry<->facet association. */
     struct list list_node;      /* In bond_slave's 'entries' list. */
 };
 
@@ -255,6 +256,12 @@ bond_reconfigure(struct bond *bond, const struct bond_settings *s)
     if (bond->balance != s->balance) {
         bond->balance = s->balance;
         revalidate = true;
+
+        if (bond->balance == BM_STABLE) {
+            VLOG_WARN_ONCE("Stable bond mode is deprecated and may be removed"
+                           " in February 2013. Please email"
+                           " dev@openvswitch.org with concerns.");
+        }
     }
 
     if (bond->basis != s->basis) {
@@ -488,7 +495,7 @@ static bool
 may_send_learning_packets(const struct bond *bond)
 {
     return bond->lacp_status == LACP_DISABLED
-        && bond->balance != BM_STABLE
+        && (bond->balance == BM_SLB || bond->balance == BM_AB)
         && bond->active_slave;
 }
 
@@ -736,7 +743,8 @@ bond_shift_load(struct bond_entry *hash, struct bond_slave *to,
     hash->tag = tag_create_random();
 }
 
-/* Pick and returns a bond_entry to migrate to 'to' (the least-loaded slave),
+/* Picks and returns a bond_entry to migrate from 'from' (the most heavily
+ * loaded bond slave) to a bond slave that has 'to_tx_bytes' bytes of load,
  * given that doing so must decrease the ratio of the load on the two slaves by
  * at least 0.1.  Returns NULL if there is no appropriate entry.
  *
@@ -765,8 +773,12 @@ choose_entry_to_migrate(const struct bond_slave *from, uint64_t to_tx_bytes)
         delta = e->tx_bytes;
         old_ratio = (double)from->tx_bytes / to_tx_bytes;
         new_ratio = (double)(from->tx_bytes - delta) / (to_tx_bytes + delta);
-        if (old_ratio - new_ratio > 0.1) {
-            /* Would decrease the ratio, move it. */
+        if (old_ratio - new_ratio > 0.1
+            && fabs(new_ratio - 1.0) < fabs(old_ratio - 1.0)) {
+            /* We're aiming for an ideal ratio of 1, meaning both the 'from'
+               and 'to' slave have the same load.  Therefore, we only move an
+               entry if it decreases the load on 'from', and brings us closer
+               to equal traffic load. */
             return e;
         }
     }
@@ -853,8 +865,8 @@ bond_rebalance(struct bond *bond, struct tag_set *tags)
             break;
         }
 
-        /* 'from' is carrying significantly more load than 'to', and that load
-         * is split across at least two different hashes. */
+        /* 'from' is carrying significantly more load than 'to'.  Pick a hash
+         * to move from 'from' to 'to'. */
         e = choose_entry_to_migrate(from, to->tx_bytes);
         if (e) {
             bond_shift_load(e, to, tags);