On Thu, Apr 28, 2016 at 07:13:42PM +0200, Florian Westphal wrote:
> Once we place all conntracks into same table iteration becomes more
> costly because the table contains conntracks that we are not interested
> in (belonging to other netns).
>
> So don't bother scanning if the current namespace has no entries.
>
> Signed-off-by: Florian Westphal <[email protected]>
> ---
> net/netfilter/nf_conntrack_core.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/net/netfilter/nf_conntrack_core.c
> b/net/netfilter/nf_conntrack_core.c
> index 29fa08b..f2e75a5 100644
> --- a/net/netfilter/nf_conntrack_core.c
> +++ b/net/netfilter/nf_conntrack_core.c
> @@ -1428,6 +1428,9 @@ void nf_ct_iterate_cleanup(struct net *net,
>
> might_sleep();
>
> + if (atomic_read(&net->ct.count) == 0)
> + return;
This optimization gets defeated with just one single conntrack (ie.
net->ct.count == 1), so I wonder if this is practical thing.
At the cost of consuming more memory per conntrack, we may consider
adding a per-net list so this iteration doesn't become a problem.
> while ((ct = get_next_corpse(net, iter, data, &bucket)) != NULL) {
> /* Time to push up daises... */
> if (del_timer(&ct->timeout))
> --
> 2.7.3
>
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