ipv4: FIB Local/MAIN table collapse
This patch is meant to collapse local and main into one by converting
tb_data from an array to a pointer. Doing this allows us to point the
local table into the main while maintaining the same variables in the
table.
As such the tb_data was converted from an array to a pointer, and a new
array called data is added in order to still provide an object for tb_data
to point to.
In order to track the origin of the fib aliases a tb_id value was added in
a hole that existed on 64b systems. Using this we can also reverse the
merge in the event that custom FIB rules are enabled.
With this patch I am seeing an improvement of 20ns to 30ns for routing
lookups as long as custom rules are not enabled, with custom rules enabled
we fall back to split tables and the original behavior.
Signed-off-by: Alexander Duyck <alexander.h.duyck@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/ip_fib.h b/include/net/ip_fib.h
index 1657604..54271ed 100644
--- a/include/net/ip_fib.h
+++ b/include/net/ip_fib.h
@@ -186,7 +186,8 @@
int tb_default;
int tb_num_default;
struct rcu_head rcu;
- unsigned long tb_data[0];
+ unsigned long *tb_data;
+ unsigned long __data[0];
};
int fib_table_lookup(struct fib_table *tb, const struct flowi4 *flp,
@@ -196,11 +197,10 @@
int fib_table_dump(struct fib_table *table, struct sk_buff *skb,
struct netlink_callback *cb);
int fib_table_flush(struct fib_table *table);
+struct fib_table *fib_trie_unmerge(struct fib_table *main_tb);
void fib_table_flush_external(struct fib_table *table);
void fib_free_table(struct fib_table *tb);
-
-
#ifndef CONFIG_IP_MULTIPLE_TABLES
#define TABLE_LOCAL_INDEX (RT_TABLE_LOCAL & (FIB_TABLE_HASHSZ - 1))
@@ -229,18 +229,13 @@
struct fib_result *res)
{
struct fib_table *tb;
- int err;
+ int err = -ENETUNREACH;
rcu_read_lock();
- for (err = 0; !err; err = -ENETUNREACH) {
- tb = fib_get_table(net, RT_TABLE_LOCAL);
- if (tb && !fib_table_lookup(tb, flp, res, FIB_LOOKUP_NOREF))
- break;
- tb = fib_get_table(net, RT_TABLE_MAIN);
- if (tb && !fib_table_lookup(tb, flp, res, FIB_LOOKUP_NOREF))
- break;
- }
+ tb = fib_get_table(net, RT_TABLE_MAIN);
+ if (tb && !fib_table_lookup(tb, flp, res, FIB_LOOKUP_NOREF))
+ err = 0;
rcu_read_unlock();
@@ -270,10 +265,6 @@
res->tclassid = 0;
for (err = 0; !err; err = -ENETUNREACH) {
- tb = rcu_dereference_rtnl(net->ipv4.fib_local);
- if (tb && !fib_table_lookup(tb, flp, res, FIB_LOOKUP_NOREF))
- break;
-
tb = rcu_dereference_rtnl(net->ipv4.fib_main);
if (tb && !fib_table_lookup(tb, flp, res, FIB_LOOKUP_NOREF))
break;
@@ -309,6 +300,7 @@
return 0;
}
#endif
+int fib_unmerge(struct net *net);
void fib_flush_external(struct net *net);
/* Exported by fib_semantics.c */
@@ -320,7 +312,7 @@
/* Exported by fib_trie.c */
void fib_trie_init(void);
-struct fib_table *fib_trie_table(u32 id);
+struct fib_table *fib_trie_table(u32 id, struct fib_table *alias);
static inline void fib_combine_itag(u32 *itag, const struct fib_result *res)
{