Florian Westphal <[email protected]> wrote: > Giuseppe Scrivano <[email protected]> wrote: > > SELinux, if enabled, registers for each new network namespace 6 > > netfilter hooks. Avoid to use synchronize_net for each new hook, but do > > it once after all the hooks are added. The net benefit on an SMP > > machine with two cores is that creating a new network namespace takes > > -40% of the original time. > > but this needs more work. > > > Signed-off-by: Giuseppe Scrivano <[email protected]> > > --- > > net/netfilter/core.c | 15 ++++++++++++--- > > 1 file changed, 12 insertions(+), 3 deletions(-) > > > > diff --git a/net/netfilter/core.c b/net/netfilter/core.c > > index 52cd2901a097..beeb0b36f429 100644 > > --- a/net/netfilter/core.c > > +++ b/net/netfilter/core.c > > @@ -252,7 +252,7 @@ static struct nf_hook_entries __rcu > > **nf_hook_entry_head(struct net *net, const > > return NULL; > > } > > > > -int nf_register_net_hook(struct net *net, const struct nf_hook_ops *reg) > > +static int __nf_register_net_hook(struct net *net, const struct > > nf_hook_ops *reg) > > Change this to return struct nf_hook_entries * > > > { > > struct nf_hook_entries *p, *new_hooks; > > struct nf_hook_entries __rcu **pp; > > @@ -291,11 +291,19 @@ int nf_register_net_hook(struct net *net, const > > struct nf_hook_ops *reg) > > #ifdef HAVE_JUMP_LABEL > > static_key_slow_inc(&nf_hooks_needed[reg->pf][reg->hooknum]); > > #endif > > - synchronize_net(); > > BUG_ON(p == new_hooks); > > kvfree(p); > > remove kvfree() > > > return 0; > > return p; > > > +int nf_register_net_hook(struct net *net, const struct nf_hook_ops *reg) > > +{ > > + int ret = __nf_register_net_hook(net, reg); > > + if (ret < 0) > > + return ret; > > + synchronize_net(); > > then free p here.
Yet another alternative is to place an rcu_head at the end of struct nf_hook_entries. This is a bit tricky because the location is not fixed due to dynamically sized array members. But if you do this you can use call_rcu to do the freeing which removes need for all but the nfqueue related synchronize_net() calls. -- To unsubscribe from this list: send the line "unsubscribe netfilter-devel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
