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Date: Sat, 8 Jun 2019 14:53:33 -0700
From: David Ahern <dsahern@...nel.org>
To: davem@...emloft.net, netdev@...r.kernel.org
Cc: idosch@...lanox.com, kafai@...com, weiwan@...gle.com,
sbrivio@...hat.com, David Ahern <dsahern@...il.com>
Subject: [PATCH v4 net-next 12/20] ipv4: Optimization for fib_info lookup with nexthops
From: David Ahern <dsahern@...il.com>
Be optimistic about re-using a fib_info when nexthop id is given and
the route does not use metrics. Avoids a memory allocation which in
most cases is expected to be freed anyways.
Signed-off-by: David Ahern <dsahern@...il.com>
---
net/ipv4/fib_semantics.c | 71 ++++++++++++++++++++++++++++++++++++++++++++----
1 file changed, 65 insertions(+), 6 deletions(-)
diff --git a/net/ipv4/fib_semantics.c b/net/ipv4/fib_semantics.c
index 2c24d8e3b126..0de895cd0621 100644
--- a/net/ipv4/fib_semantics.c
+++ b/net/ipv4/fib_semantics.c
@@ -325,14 +325,32 @@ static inline unsigned int fib_devindex_hashfn(unsigned int val)
(val >> (DEVINDEX_HASHBITS * 2))) & mask;
}
-static inline unsigned int fib_info_hashfn(const struct fib_info *fi)
+static unsigned int fib_info_hashfn_1(int init_val, u8 protocol, u8 scope,
+ u32 prefsrc, u32 priority)
+{
+ unsigned int val = init_val;
+
+ val ^= (protocol << 8) | scope;
+ val ^= prefsrc;
+ val ^= priority;
+
+ return val;
+}
+
+static unsigned int fib_info_hashfn_result(unsigned int val)
{
unsigned int mask = (fib_info_hash_size - 1);
- unsigned int val = fi->fib_nhs;
- val ^= (fi->fib_protocol << 8) | fi->fib_scope;
- val ^= (__force u32)fi->fib_prefsrc;
- val ^= fi->fib_priority;
+ return (val ^ (val >> 7) ^ (val >> 12)) & mask;
+}
+
+static inline unsigned int fib_info_hashfn(struct fib_info *fi)
+{
+ unsigned int val;
+
+ val = fib_info_hashfn_1(fi->fib_nhs, fi->fib_protocol,
+ fi->fib_scope, (__force u32)fi->fib_prefsrc,
+ fi->fib_priority);
if (fi->nh) {
val ^= fib_devindex_hashfn(fi->nh->id);
@@ -342,7 +360,40 @@ static inline unsigned int fib_info_hashfn(const struct fib_info *fi)
} endfor_nexthops(fi)
}
- return (val ^ (val >> 7) ^ (val >> 12)) & mask;
+ return fib_info_hashfn_result(val);
+}
+
+/* no metrics, only nexthop id */
+static struct fib_info *fib_find_info_nh(struct net *net,
+ const struct fib_config *cfg)
+{
+ struct hlist_head *head;
+ struct fib_info *fi;
+ unsigned int hash;
+
+ hash = fib_info_hashfn_1(fib_devindex_hashfn(cfg->fc_nh_id),
+ cfg->fc_protocol, cfg->fc_scope,
+ (__force u32)cfg->fc_prefsrc,
+ cfg->fc_priority);
+ hash = fib_info_hashfn_result(hash);
+ head = &fib_info_hash[hash];
+
+ hlist_for_each_entry(fi, head, fib_hash) {
+ if (!net_eq(fi->fib_net, net))
+ continue;
+ if (!fi->nh || fi->nh->id != cfg->fc_nh_id)
+ continue;
+ if (cfg->fc_protocol == fi->fib_protocol &&
+ cfg->fc_scope == fi->fib_scope &&
+ cfg->fc_prefsrc == fi->fib_prefsrc &&
+ cfg->fc_priority == fi->fib_priority &&
+ cfg->fc_type == fi->fib_type &&
+ cfg->fc_table == fi->fib_tb_id &&
+ !((cfg->fc_flags ^ fi->fib_flags) & ~RTNH_COMPARE_MASK))
+ return fi;
+ }
+
+ return NULL;
}
static struct fib_info *fib_find_info(struct fib_info *nfi)
@@ -1309,6 +1360,14 @@ struct fib_info *fib_create_info(struct fib_config *cfg,
}
if (cfg->fc_nh_id) {
+ if (!cfg->fc_mx) {
+ fi = fib_find_info_nh(net, cfg);
+ if (fi) {
+ fi->fib_treeref++;
+ return fi;
+ }
+ }
+
nh = nexthop_find_by_id(net, cfg->fc_nh_id);
if (!nh) {
NL_SET_ERR_MSG(extack, "Nexthop id does not exist");
--
2.11.0
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