Hi Florian,
a few comments below.
On Tue, Feb 11, 2025 at 02:03:06PM +0100, Florian Westphal wrote:
> Dumping all conntrack entries via proc interface can take hours due to
> linear search to skip entries dumped so far in each cycle.
>
> Apply same strategy used to speed up ipvs proc reading done in
> commit 178883fd039d ("ipvs: speed up reads from ip_vs_conn proc file")
> to nf_conntrack.
>
> Note that the ctnetlink interface doesn't suffer from this problem.
>
> Signed-off-by: Florian Westphal <fw@xxxxxxxxx>
> ---
> net/netfilter/nf_conntrack_standalone.c | 73 +++++++++++++------------
> 1 file changed, 38 insertions(+), 35 deletions(-)
>
> diff --git a/net/netfilter/nf_conntrack_standalone.c b/net/netfilter/nf_conntrack_standalone.c
> index 502cf10aab41..2a79e690470a 100644
> --- a/net/netfilter/nf_conntrack_standalone.c
> +++ b/net/netfilter/nf_conntrack_standalone.c
> @@ -98,51 +98,34 @@ struct ct_iter_state {
> struct seq_net_private p;
> struct hlist_nulls_head *hash;
> unsigned int htable_size;
> + unsigned int skip_elems;
> unsigned int bucket;
> u_int64_t time_now;
> };
>
> -static struct hlist_nulls_node *ct_get_first(struct seq_file *seq)
> +static struct nf_conntrack_tuple_hash *ct_get_next(struct ct_iter_state *st)
> {
> - struct ct_iter_state *st = seq->private;
> + struct nf_conntrack_tuple_hash *h;
> struct hlist_nulls_node *n;
> + unsigned int i;
>
> - for (st->bucket = 0;
> - st->bucket < st->htable_size;
> - st->bucket++) {
> - n = rcu_dereference(
> - hlist_nulls_first_rcu(&st->hash[st->bucket]));
> - if (!is_a_nulls(n))
> - return n;
> - }
> - return NULL;
> -}
> + for (i = st->bucket; i < st->htable_size; i++) {
> + unsigned int skip = 0;
>
> -static struct hlist_nulls_node *ct_get_next(struct seq_file *seq,
> - struct hlist_nulls_node *head)
> -{
> - struct ct_iter_state *st = seq->private;
> + hlist_nulls_for_each_entry(h, n, &st->hash[i], hnnode) {
hlist_nulls_for_each_entry_rcu ?
> + if (skip >= st->skip_elems) {
> + st->bucket = i;
> + return h;
> + }
>
> - head = rcu_dereference(hlist_nulls_next_rcu(head));
> - while (is_a_nulls(head)) {
> - if (likely(get_nulls_value(head) == st->bucket)) {
> - if (++st->bucket >= st->htable_size)
> - return NULL;
> + ++skip;
> }
> - head = rcu_dereference(
> - hlist_nulls_first_rcu(&st->hash[st->bucket]));
This does not rewind if get_nulls_value(head) != st->bucket),
not needed anymore?
> - }
> - return head;
> -}
>
> -static struct hlist_nulls_node *ct_get_idx(struct seq_file *seq, loff_t pos)
> -{
> - struct hlist_nulls_node *head = ct_get_first(seq);
> + st->skip_elems = 0;
> + }
>
> - if (head)
> - while (pos && (head = ct_get_next(seq, head)))
> - pos--;
> - return pos ? NULL : head;
> + st->bucket = i;
> + return NULL;
> }
>
> static void *ct_seq_start(struct seq_file *seq, loff_t *pos)
> @@ -154,13 +137,33 @@ static void *ct_seq_start(struct seq_file *seq, loff_t *pos)
> rcu_read_lock();
>
> nf_conntrack_get_ht(&st->hash, &st->htable_size);
> - return ct_get_idx(seq, *pos);
> +
> + if (*pos == 0) {
> + st->skip_elems = 0;
> + st->bucket = 0;
> + }
> +
> + return ct_get_next(st);
> }
>
> static void *ct_seq_next(struct seq_file *s, void *v, loff_t *pos)
> {
> + struct nf_conntrack_tuple_hash *h = v;
> + struct ct_iter_state *st = s->private;
> + struct hlist_nulls_node *n;
> +
> (*pos)++;
> - return ct_get_next(s, v);
> +
> + /* more on same hash chain? */
> + n = rcu_dereference(hlist_nulls_next_rcu(&h->hnnode));
> + if (n && !is_a_nulls(n)) {
> + st->skip_elems++;
> + return hlist_nulls_entry(n, struct nf_conntrack_tuple_hash, hnnode);
> + }
> +
> + st->skip_elems = 0;
> + st->bucket++;
> + return ct_get_next(st);
> }
>
> static void ct_seq_stop(struct seq_file *s, void *v)
> --
> 2.45.3
>
>
