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authorEric Dumazet <eric.dumazet@gmail.com>2011-11-17 03:13:26 +0000
committerDavid S. Miller <davem@davemloft.net>2011-11-17 17:06:08 -0500
commitadc9300e78e6091a7eaa1821213836379d4dbaa8 (patch)
treeb2d075990b32e8c21129851bf1b1adf4cdc441f1 /net/core/sysctl_net_core.c
parentd6f144830bdfa5fcf116e9ab8fc6a60d23fa623d (diff)
net: use jump_label to shortcut RPS if not setup
Most machines dont use RPS/RFS, and pay a fair amount of instructions in netif_receive_skb() / netif_rx() / get_rps_cpu() just to discover RPS/RFS is not setup. Add a jump_label named rps_needed. If no device rps_map or global rps_sock_flow_table is setup, netif_receive_skb() / netif_rx() do a single instruction instead of many ones, including conditional jumps. jmp +0 (if CONFIG_JUMP_LABEL=y) Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> CC: Tom Herbert <therbert@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/core/sysctl_net_core.c')
-rw-r--r--net/core/sysctl_net_core.c9
1 files changed, 7 insertions, 2 deletions
diff --git a/net/core/sysctl_net_core.c b/net/core/sysctl_net_core.c
index 77a65f031488..d05559d4d9cd 100644
--- a/net/core/sysctl_net_core.c
+++ b/net/core/sysctl_net_core.c
@@ -68,8 +68,13 @@ static int rps_sock_flow_sysctl(ctl_table *table, int write,
if (sock_table != orig_sock_table) {
rcu_assign_pointer(rps_sock_flow_table, sock_table);
- synchronize_rcu();
- vfree(orig_sock_table);
+ if (sock_table)
+ jump_label_inc(&rps_needed);
+ if (orig_sock_table) {
+ jump_label_dec(&rps_needed);
+ synchronize_rcu();
+ vfree(orig_sock_table);
+ }
}
}