On Fri, Apr 26, 2019 at 01:13:41PM +0100, Edward Cree wrote:
> On 25/04/2019 23:33, Pablo Neira Ayuso wrote:
> > On Thu, Apr 25, 2019 at 02:23:08PM +0100, Edward Cree wrote:
> >> On 24/04/2019 16:03, Edward Cree wrote:
> >>> static int efx_tc_flower_replace(struct efx_nic *efx,
> >>> struct net_device *net_dev,
> >>> struct tc_cls_flower_offload *tc)
> >>> {
> >>> struct efx_tc_action_set *act;
> >>>
> >>> /* parse the match */
> >>>
> >>> tcf_exts_for_each_action(i, a, tc->exts) {
> >>> if (a->ops && a->ops->stats_update) {
> >>> /* act is the hw action we're building */
> >>> act->count = allocate_a_counter();
> >> Also, this was actually taking a->tcfa_index, allowing multiple rules to
> >> share a counter. The action index doesn't seem to be available in the
> >> new flow_offload API.
> > Could you show a bit more code to see how you use a->tcfa_index from
> > your efx_tc_flower_replace()?
> >
> > Thanks.
> Sure; this block is (still slightly abridged)
>
> if (a->ops && a->ops->stats_update) {
> struct efx_tc_counter_index *ctr;
>
> ctr = efx_tc_flower_get_counter_by_index(efx, a->tcfa_index);
> if (IS_ERR(ctr)) {
> rc = PTR_ERR(ctr);
> goto release;
> }
> act->count = ctr;
> act->count_action_idx = i;
> efx_tc_calculate_count_delta(act);
> }
>
> and we have
>
> struct efx_tc_counter_index {
> u32 tcfa_index;
> struct rhash_head linkage;
> refcount_t ref;
> u32 fw_id;
> };
>
> const static struct rhashtable_params efx_tc_counter_ht_params = {
> .key_len = offsetof(struct efx_tc_counter_index, linkage),
> .key_offset = 0,
> .head_offset = offsetof(struct efx_tc_counter_index, linkage),
> };
>
> static struct efx_tc_counter_index *efx_tc_flower_get_counter_by_index(
> struct efx_nic *efx, u32 idx)
> {
> struct efx_tc_counter_index *ctr, *old;
> long rc;
>
> ctr = kzalloc(sizeof(*ctr), GFP_USER);
> if (!ctr)
> return ERR_PTR(-ENOMEM);
> ctr->tcfa_index = idx;
> old = rhashtable_lookup_get_insert_fast(&efx->tc->counter_ht,
> &ctr->linkage,
> efx_tc_counter_ht_params);
> if (old) {
> /* don't need our new entry */
> kfree(ctr);
> if (!refcount_inc_not_zero(&old->ref))
> return ERR_PTR(-EAGAIN);
> /* existing entry found */
> ctr = old;
> } else {
> rc = efx_tc_flower_allocate_counter(efx);
> if (rc < 0) {
> rhashtable_remove_fast(&efx->tc->counter_ht,
> &ctr->linkage,
> efx_tc_counter_ht_params);
> kfree(ctr);
> return ERR_PTR(rc);
> }
> ctr->fw_id = rc;
> refcount_inc(&ctr->ref);
> }
> return ctr;
> }
>
> Thus if (and only if) two TC actions have the same tcfa_index, they will
> share a single counter in the HW.
> I gathered from a previous conversation with Jamal[1] that that was the
> correct behaviour:
> > Note, your counters should also be shareable; example, count all
> > the drops in one counter across multiple flows as in the following
> > case where counter index 1 is used.
> >
> > tc flower match foo action drop index 1
> > tc flower match bar action drop index 1
The flow_action_entry structure needs a new 'counter_index' field to
store this. The tc_setup_flow_action() function needs to be updated
for this for the FLOW_ACTION_{ACCEPT,DROP,REDIRECT,MIRRED} cases to
set this entry->counter_index field to tcfa_index, so the driver has
access to this.
Thanks.
