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| author | Eric Dumazet <eric.dumazet@gmail.com> | 2010-10-14 05:56:18 +0000 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2010-10-17 13:49:14 -0700 |
| commit | 8e602ce2980fd6941dc0d3dda12e5095e8206f34 (patch) | |
| tree | 1a0ea79a6db1b01660cc034c822d02c95e356388 /include/net/net_namespace.h | |
| parent | c60ce4e265404ca42ba860401f4b0f1e97332a67 (diff) | |
| download | op-kernel-dev-8e602ce2980fd6941dc0d3dda12e5095e8206f34.zip op-kernel-dev-8e602ce2980fd6941dc0d3dda12e5095e8206f34.tar.gz | |
netns: reorder fields in struct net
In a network bench, I noticed an unfortunate false sharing between
'loopback_dev' and 'count' fields in "struct net".
'count' is written each time a socket is created or destroyed, while
loopback_dev might be often read in routing code.
Move loopback_dev in a read mostly section of "struct net"
Note: struct netns_xfrm is cache line aligned on SMP.
(It contains a "struct dst_ops")
Move it at the end to avoid holes, and reduce sizeof(struct net) by 128
bytes on ia32.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/net/net_namespace.h')
| -rw-r--r-- | include/net/net_namespace.h | 17 |
1 files changed, 10 insertions, 7 deletions
diff --git a/include/net/net_namespace.h b/include/net/net_namespace.h index bd10a79..65af9a0 100644 --- a/include/net/net_namespace.h +++ b/include/net/net_namespace.h @@ -41,6 +41,8 @@ struct net { * destroy on demand */ #endif + spinlock_t rules_mod_lock; + struct list_head list; /* list of network namespaces */ struct list_head cleanup_list; /* namespaces on death row */ struct list_head exit_list; /* Use only net_mutex */ @@ -52,7 +54,8 @@ struct net { struct ctl_table_set sysctls; #endif - struct net_device *loopback_dev; /* The loopback */ + struct sock *rtnl; /* rtnetlink socket */ + struct sock *genl_sock; struct list_head dev_base_head; struct hlist_head *dev_name_head; @@ -60,11 +63,9 @@ struct net { /* core fib_rules */ struct list_head rules_ops; - spinlock_t rules_mod_lock; - struct sock *rtnl; /* rtnetlink socket */ - struct sock *genl_sock; + struct net_device *loopback_dev; /* The loopback */ struct netns_core core; struct netns_mib mib; struct netns_packet packet; @@ -84,13 +85,15 @@ struct net { struct sock *nfnl; struct sock *nfnl_stash; #endif -#ifdef CONFIG_XFRM - struct netns_xfrm xfrm; -#endif #ifdef CONFIG_WEXT_CORE struct sk_buff_head wext_nlevents; #endif struct net_generic *gen; + + /* Note : following structs are cache line aligned */ +#ifdef CONFIG_XFRM + struct netns_xfrm xfrm; +#endif }; |
