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Message-ID: <20150305230029.1987.68126.stgit@ahduyck-vm-fedora20>
Date: Thu, 05 Mar 2015 15:12:12 -0800
From: Alexander Duyck <alexander.h.duyck@...hat.com>
To: netdev@...r.kernel.org
Cc: jiri@...nulli.us, sfeldma@...il.com, davem@...emloft.net
Subject: [RFC PATCH] 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.
Signed-off-by: Alexander Duyck <alexander.h.duyck@...hat.com>
---
This is the latest version I have for the combined local/main trie. It
applies on top of the patches I submitted earlier today.
The performance gains with this patch applied are fairly impressive. I
have seen reductions of up to 40ns (from ~120ns to ~80ns) for routing
look-ups with the depth 7 local and main trie.
However, I belive this breaks things if custom rules are defined that try
to place another table between the local and main look-ups. As such this
approach may only be usable if there are no custom rules or
CONFIG_IP_MULTIPLE_TABLES is not defined. Another patch would be needed to
split or merge the tables depending on if custom rules are enabled or not.
include/net/ip_fib.h | 12 +++---------
net/ipv4/fib_frontend.c | 17 ++++++++++-------
net/ipv4/fib_trie.c | 23 +++++++++++++++++++----
3 files changed, 32 insertions(+), 20 deletions(-)
diff --git a/include/net/ip_fib.h b/include/net/ip_fib.h
index 825cb28..29b9e63 100644
--- a/include/net/ip_fib.h
+++ b/include/net/ip_fib.h
@@ -186,7 +186,8 @@ struct fib_table {
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,
@@ -233,9 +234,6 @@ static inline int fib_lookup(struct net *net, const struct flowi4 *flp,
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;
@@ -269,10 +267,6 @@ static inline int fib_lookup(struct net *net, struct flowi4 *flp,
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;
@@ -318,7 +312,7 @@ void fib_select_multipath(struct fib_result *res);
/* 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)
{
diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c
index 220c4b4..b1adda9 100644
--- a/net/ipv4/fib_frontend.c
+++ b/net/ipv4/fib_frontend.c
@@ -52,14 +52,14 @@ static int __net_init fib4_rules_init(struct net *net)
{
struct fib_table *local_table, *main_table;
- local_table = fib_trie_table(RT_TABLE_LOCAL);
- if (local_table == NULL)
- return -ENOMEM;
-
- main_table = fib_trie_table(RT_TABLE_MAIN);
+ main_table = fib_trie_table(RT_TABLE_MAIN, NULL);
if (main_table == NULL)
goto fail;
+ local_table = fib_trie_table(RT_TABLE_LOCAL, main_table);
+ if (local_table == NULL)
+ return -ENOMEM;
+
hlist_add_head_rcu(&local_table->tb_hlist,
&net->ipv4.fib_table_hash[TABLE_LOCAL_INDEX]);
hlist_add_head_rcu(&main_table->tb_hlist,
@@ -74,7 +74,7 @@ fail:
struct fib_table *fib_new_table(struct net *net, u32 id)
{
- struct fib_table *tb;
+ struct fib_table *tb, *alias = NULL;
unsigned int h;
if (id == 0)
@@ -83,7 +83,10 @@ struct fib_table *fib_new_table(struct net *net, u32 id)
if (tb)
return tb;
- tb = fib_trie_table(id);
+ if (id == RT_TABLE_LOCAL)
+ alias = fib_new_table(net, RT_TABLE_MAIN);
+
+ tb = fib_trie_table(id, alias);
if (!tb)
return NULL;
diff --git a/net/ipv4/fib_trie.c b/net/ipv4/fib_trie.c
index 86f2d50..cf3ff18 100644
--- a/net/ipv4/fib_trie.c
+++ b/net/ipv4/fib_trie.c
@@ -1220,7 +1220,7 @@ static inline t_key prefix_mismatch(t_key key, struct key_vector *n)
int fib_table_lookup(struct fib_table *tb, const struct flowi4 *flp,
struct fib_result *res, int fib_flags)
{
- struct trie *t = (struct trie *)tb->tb_data;
+ struct trie *t = (struct trie *) tb->tb_data;
#ifdef CONFIG_IP_FIB_TRIE_STATS
struct trie_use_stats __percpu *stats = t->stats;
#endif
@@ -1628,7 +1628,8 @@ static void __trie_free_rcu(struct rcu_head *head)
#ifdef CONFIG_IP_FIB_TRIE_STATS
struct trie *t = (struct trie *)tb->tb_data;
- free_percpu(t->stats);
+ if (tb->tb_data == tb->__data)
+ free_percpu(t->stats);
#endif /* CONFIG_IP_FIB_TRIE_STATS */
kfree(tb);
}
@@ -1655,6 +1656,12 @@ static int fn_trie_dump_leaf(struct key_vector *l, struct fib_table *tb,
continue;
}
+ if (tb->tb_id == ((fa->fa_type == RTN_LOCAL) ? RT_TABLE_MAIN :
+ RT_TABLE_LOCAL)) {
+ i++;
+ continue;
+ }
+
if (fib_dump_info(skb, NETLINK_CB(cb->skb).portid,
cb->nlh->nlmsg_seq,
RTM_NEWROUTE,
@@ -1721,18 +1728,26 @@ void __init fib_trie_init(void)
0, SLAB_PANIC, NULL);
}
-struct fib_table *fib_trie_table(u32 id)
+struct fib_table *fib_trie_table(u32 id, struct fib_table *alias)
{
struct fib_table *tb;
struct trie *t;
+ size_t sz = sizeof(*tb);
- tb = kzalloc(sizeof(*tb) + sizeof(struct trie), GFP_KERNEL);
+ if (!alias)
+ sz += sizeof(struct trie);
+
+ tb = kzalloc(sz, GFP_KERNEL);
if (tb == NULL)
return NULL;
tb->tb_id = id;
tb->tb_default = -1;
tb->tb_num_default = 0;
+ tb->tb_data = (alias ? alias->__data : tb->__data);
+
+ if (alias)
+ return tb;
t = (struct trie *) tb->tb_data;
t->kv[0].pos = KEYLENGTH;
--
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