diff options
| author | Eric Dumazet <eric.dumazet@gmail.com> | 2011-11-18 17:32:46 +0000 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2011-11-21 16:38:08 -0500 |
| commit | a2d7ec58ac09f30ab726f216827f7c7095b2a98f (patch) | |
| tree | 1b733090406abc18c42308e84703dcb703e15125 | |
| parent | 9205fd9ccab8ef51ad771c1917eed7b2f2225d45 (diff) | |
netfilter: use jump_label for nf_hooks
On configs where CONFIG_JUMP_LABEL=y, we can replace in fast path a
load/compare/conditional jump by a single jump with no dcache reference.
Jump target is modified as soon as nf_hooks[pf][hook] switches from
empty state to non empty states. jump_label state is kept outside of
nf_hooks array so has no cost on cpu caches.
This patch removes the test on CONFIG_NETFILTER_DEBUG : No need to call
nf_hook_slow() at all if nf_hooks[pf][hook] is empty, this didnt give
useful information, but slowed down things a lot.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
CC: Patrick McHardy <kaber@trash.net>
CC: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | include/linux/netfilter.h | 26 | ||||
| -rw-r--r-- | net/netfilter/core.c | 13 |
2 files changed, 33 insertions, 6 deletions
diff --git a/include/linux/netfilter.h b/include/linux/netfilter.h index 857f5026ced..b809265607d 100644 --- a/include/linux/netfilter.h +++ b/include/linux/netfilter.h @@ -162,6 +162,24 @@ extern struct ctl_path nf_net_ipv4_netfilter_sysctl_path[]; extern struct list_head nf_hooks[NFPROTO_NUMPROTO][NF_MAX_HOOKS]; +#if defined(CONFIG_JUMP_LABEL) +#include <linux/jump_label.h> +extern struct jump_label_key nf_hooks_needed[NFPROTO_NUMPROTO][NF_MAX_HOOKS]; +static inline bool nf_hooks_active(u_int8_t pf, unsigned int hook) +{ + if (__builtin_constant_p(pf) && + __builtin_constant_p(hook)) + return static_branch(&nf_hooks_needed[pf][hook]); + + return !list_empty(&nf_hooks[pf][hook]); +} +#else +static inline bool nf_hooks_active(u_int8_t pf, unsigned int hook) +{ + return !list_empty(&nf_hooks[pf][hook]); +} +#endif + int nf_hook_slow(u_int8_t pf, unsigned int hook, struct sk_buff *skb, struct net_device *indev, struct net_device *outdev, int (*okfn)(struct sk_buff *), int thresh); @@ -179,11 +197,9 @@ static inline int nf_hook_thresh(u_int8_t pf, unsigned int hook, struct net_device *outdev, int (*okfn)(struct sk_buff *), int thresh) { -#ifndef CONFIG_NETFILTER_DEBUG - if (list_empty(&nf_hooks[pf][hook])) - return 1; -#endif - return nf_hook_slow(pf, hook, skb, indev, outdev, okfn, thresh); + if (nf_hooks_active(pf, hook)) + return nf_hook_slow(pf, hook, skb, indev, outdev, okfn, thresh); + return 1; } static inline int nf_hook(u_int8_t pf, unsigned int hook, struct sk_buff *skb, diff --git a/net/netfilter/core.c b/net/netfilter/core.c index afca6c78948..4aa0f4b19bd 100644 --- a/net/netfilter/core.c +++ b/net/netfilter/core.c @@ -54,6 +54,12 @@ EXPORT_SYMBOL_GPL(nf_unregister_afinfo); struct list_head nf_hooks[NFPROTO_NUMPROTO][NF_MAX_HOOKS] __read_mostly; EXPORT_SYMBOL(nf_hooks); + +#if defined(CONFIG_JUMP_LABEL) +struct jump_label_key nf_hooks_needed[NFPROTO_NUMPROTO][NF_MAX_HOOKS]; +EXPORT_SYMBOL(nf_hooks_needed); +#endif + static DEFINE_MUTEX(nf_hook_mutex); int nf_register_hook(struct nf_hook_ops *reg) @@ -70,6 +76,9 @@ int nf_register_hook(struct nf_hook_ops *reg) } list_add_rcu(®->list, elem->list.prev); mutex_unlock(&nf_hook_mutex); +#if defined(CONFIG_JUMP_LABEL) + jump_label_inc(&nf_hooks_needed[reg->pf][reg->hooknum]); +#endif return 0; } EXPORT_SYMBOL(nf_register_hook); @@ -79,7 +88,9 @@ void nf_unregister_hook(struct nf_hook_ops *reg) mutex_lock(&nf_hook_mutex); list_del_rcu(®->list); mutex_unlock(&nf_hook_mutex); - +#if defined(CONFIG_JUMP_LABEL) + jump_label_dec(&nf_hooks_needed[reg->pf][reg->hooknum]); +#endif synchronize_net(); } EXPORT_SYMBOL(nf_unregister_hook); |