target/linux/generic/patches-3.18/080-23-fib_trie-Use-empty_children-instead-of-counting-empt.patch

   1 From: Alexander Duyck <alexander.h.duyck@redhat.com>
   2 Date: Thu, 22 Jan 2015 15:51:33 -0800
   3 Subject: [PATCH] fib_trie: Use empty_children instead of counting empty nodes
   4  in stats collection
   5
   6 It doesn't make much sense to count the pointers ourselves when
   7 empty_children already has a count for the number of NULL pointers stored
   8 in the tnode.  As such save ourselves the cycles and just use
   9 empty_children.
  10
  11 Signed-off-by: Alexander Duyck <alexander.h.duyck@redhat.com>
  12 Signed-off-by: David S. Miller <davem@davemloft.net>
  13 ---
  14
  15 --- a/net/ipv4/fib_trie.c
  16 +++ b/net/ipv4/fib_trie.c
  17 @@ -1954,16 +1954,10 @@ static void trie_collect_stats(struct tr
  18                         hlist_for_each_entry_rcu(li, &n->list, hlist)
  19                                 ++s->prefixes;
  20                 } else {
  21 -                       unsigned long i;
  22 -
  23                         s->tnodes++;
  24                         if (n->bits < MAX_STAT_DEPTH)
  25                                 s->nodesizes[n->bits]++;
  26 -
  27 -                       for (i = tnode_child_length(n); i--;) {
  28 -                               if (!rcu_access_pointer(n->child[i]))
  29 -                                       s->nullpointers++;
  30 -                       }
  31 +                       s->nullpointers += n->empty_children;
  32                 }
  33         }
  34         rcu_read_unlock();