1 files changed, 23 insertions, 4 deletions

diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 36ebb4ad8a0a..7d7d4b17c0f0 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -99,6 +99,10 @@
 #define INFINITY_LIFE_TIME      0xFFFFFFFF
 #define TIME_DELTA(a, b) ((unsigned long)((long)(a) - (long)(b)))
 
+#define ADDRCONF_TIMER_FUZZ_MINUS       (HZ > 50 ? HZ/50 : 1)
+#define ADDRCONF_TIMER_FUZZ             (HZ / 4)
+#define ADDRCONF_TIMER_FUZZ_MAX         (HZ)
+
 #ifdef CONFIG_SYSCTL
 static void addrconf_sysctl_register(struct inet6_dev *idev);
 static void addrconf_sysctl_unregister(struct inet6_dev *idev);
@@ -3107,15 +3111,15 @@ int ipv6_chk_home_addr(struct net *net, struct in6_addr *addr)
 
 static void addrconf_verify(unsigned long foo)
 {
+        unsigned long now, next, next_sec, next_sched;
         struct inet6_ifaddr *ifp;
         struct hlist_node *node;
-        unsigned long now, next;
         int i;
 
         rcu_read_lock_bh();
         spin_lock(&addrconf_verify_lock);
         now = jiffies;
-        next = now + ADDR_CHECK_FREQUENCY;
+        next = round_jiffies_up(now + ADDR_CHECK_FREQUENCY);
 
         del_timer(&addr_chk_timer);
 
@@ -3129,7 +3133,8 @@ restart:
                                 continue;
 
                         spin_lock(&ifp->lock);
-                        age = (now - ifp->tstamp) / HZ;
+                        /* We try to batch several events at once. */
+                        age = (now - ifp->tstamp + ADDRCONF_TIMER_FUZZ_MINUS) / HZ;
 
                         if (ifp->valid_lft != INFINITY_LIFE_TIME &&
                             age >= ifp->valid_lft) {
@@ -3199,7 +3204,21 @@ restart:
                 }
         }
 
-        addr_chk_timer.expires = time_before(next, jiffies + HZ) ? jiffies + HZ : next;
+        next_sec = round_jiffies_up(next);
+        next_sched = next;
+
+        /* If rounded timeout is accurate enough, accept it. */
+        if (time_before(next_sec, next + ADDRCONF_TIMER_FUZZ))
+                next_sched = next_sec;
+
+        /* And minimum interval is ADDRCONF_TIMER_FUZZ_MAX. */
+        if (time_before(next_sched, jiffies + ADDRCONF_TIMER_FUZZ_MAX))
+                next_sched = jiffies + ADDRCONF_TIMER_FUZZ_MAX;
+
+        ADBG((KERN_DEBUG "now = %lu, schedule = %lu, rounded schedule = %lu => %lu\n",
+              now, next, next_sec, next_sched));
+
+        addr_chk_timer.expires = next_sched;
         add_timer(&addr_chk_timer);
         spin_unlock(&addrconf_verify_lock);
         rcu_read_unlock_bh();