ipv4: avoid parallel route cache gc executions

[pandora-kernel.git] / net / ipv4 / route.c

diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 5706bc1..6b7108e 100644 (file)
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -988,6 +988,7 @@ static void __do_rt_garbage_collect(int elasticity, int min_interval)
        static unsigned long last_gc;
        static int rover;
        static int equilibrium;
+       static DEFINE_SPINLOCK(rt_gc_lock);
        struct rtable *rth;
        struct rtable __rcu **rthp;
        unsigned long now = jiffies;
@@ -999,6 +1000,8 @@ static void __do_rt_garbage_collect(int elasticity, int min_interval)
         * do not make it too frequently.
         */
 
+       spin_lock(&rt_gc_lock);
+
        RT_CACHE_STAT_INC(gc_total);
 
        if (now - last_gc < min_interval &&
@@ -1091,7 +1094,7 @@ static void __do_rt_garbage_collect(int elasticity, int min_interval)
        if (net_ratelimit())
                printk(KERN_WARNING "dst cache overflow\n");
        RT_CACHE_STAT_INC(gc_dst_overflow);
-       return;
+       goto out;
 
 work_done:
        expire += min_interval;
@@ -1099,7 +1102,8 @@ work_done:
            dst_entries_get_fast(&ipv4_dst_ops) < ipv4_dst_ops.gc_thresh ||
            dst_entries_get_slow(&ipv4_dst_ops) < ipv4_dst_ops.gc_thresh)
                expire = ip_rt_gc_timeout;
-out:   return;
+out:
+       spin_unlock(&rt_gc_lock);
 }
 
 static void __rt_garbage_collect(struct work_struct *w)
@@ -1174,7 +1178,7 @@ static struct rtable *rt_intern_hash(unsigned hash, struct rtable *rt,
        unsigned long   now;
        u32             min_score;
        int             chain_length;
-       int attempts = !in_softirq();
+       int attempts = 1;
 
 restart:
        chain_length = 0;
@@ -1311,8 +1315,15 @@ restart:
                           can be released. Try to shrink route cache,
                           it is most likely it holds some neighbour records.
                         */
-                       if (attempts-- > 0) {
-                               __do_rt_garbage_collect(1, 0);
+                       if (!in_softirq() && attempts-- > 0) {
+                               static DEFINE_SPINLOCK(lock);
+
+                               if (spin_trylock(&lock)) {
+                                       __do_rt_garbage_collect(1, 0);
+                                       spin_unlock(&lock);
+                               } else {
+                                       spin_unlock_wait(&lock);
+                               }
                                goto restart;
                        }