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authorKrishna Kumar <krkumar2@in.ibm.com>2009-02-18 17:55:02 -0800
committerDavid S. Miller <davem@davemloft.net>2009-02-18 17:55:02 -0800
commite88721f87d8caa679e62d6004a9a5661f1ac7b0e (patch)
tree4e5ad54f7445631ac2ec5750dbe245e6c26a140c
parent38bb045d493cc166920834087acd934dedc1b5d5 (diff)
net: Optimize skb_tx_hash() by eliminating a comparison
Optimize skb_tx_hash() by eliminating a comparison that executes for every packet. skb_tx_hashrnd initialization is moved to a later part of the startup sequence, namely after the "random" driver is initialized. Rebooted the system three times and verified that the code generates different random numbers each time. Signed-off-by: Krishna Kumar <krkumar2@in.ibm.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--net/core/dev.c14
1 files changed, 8 insertions, 6 deletions
diff --git a/net/core/dev.c b/net/core/dev.c
index d393fc997cd..5493394118f 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -1745,17 +1745,11 @@ out_kfree_skb:
}
static u32 skb_tx_hashrnd;
-static int skb_tx_hashrnd_initialized = 0;
static u16 skb_tx_hash(struct net_device *dev, struct sk_buff *skb)
{
u32 hash;
- if (unlikely(!skb_tx_hashrnd_initialized)) {
- get_random_bytes(&skb_tx_hashrnd, 4);
- skb_tx_hashrnd_initialized = 1;
- }
-
if (skb_rx_queue_recorded(skb)) {
hash = skb_get_rx_queue(skb);
} else if (skb->sk && skb->sk->sk_hash) {
@@ -5291,6 +5285,14 @@ out:
subsys_initcall(net_dev_init);
+static int __init initialize_hashrnd(void)
+{
+ get_random_bytes(&skb_tx_hashrnd, sizeof(skb_tx_hashrnd));
+ return 0;
+}
+
+late_initcall_sync(initialize_hashrnd);
+
EXPORT_SYMBOL(__dev_get_by_index);
EXPORT_SYMBOL(__dev_get_by_name);
EXPORT_SYMBOL(__dev_remove_pack);