Re: [patch net-next v2 01/12] flow_offload: Introduce offload of HW stats type

[Jiri Pirko <jiri@resnulli.us>]

Sat, Feb 29, 2020 at 08:29:47PM CET, pablo@netfilter.org wrote:
>On Fri, Feb 28, 2020 at 06:24:54PM +0100, Jiri Pirko wrote:
>> From: Jiri Pirko <jiri@mellanox.com>
>> 
>> Initially, pass "ANY" (struct is zeroed) to the drivers as that is the
>> current implicit value coming down to flow_offload. Add a bool
>> indicating that entries have mixed HW stats type.
>> 
>> Signed-off-by: Jiri Pirko <jiri@mellanox.com>
>> ---
>> v1->v2:
>> - moved to actions
>> - add mixed bool
>> ---
>>  include/net/flow_offload.h | 6 ++++++
>>  1 file changed, 6 insertions(+)
>> 
>> diff --git a/include/net/flow_offload.h b/include/net/flow_offload.h
>> index 4e864c34a1b0..eee1cbc5db3c 100644
>> --- a/include/net/flow_offload.h
>> +++ b/include/net/flow_offload.h
>> @@ -154,6 +154,10 @@ enum flow_action_mangle_base {
>>  	FLOW_ACT_MANGLE_HDR_TYPE_UDP,
>>  };
>>  
>> +enum flow_action_hw_stats_type {
>> +	FLOW_ACTION_HW_STATS_TYPE_ANY,
>> +};
>> +
>>  typedef void (*action_destr)(void *priv);
>>  
>>  struct flow_action_cookie {
>> @@ -168,6 +172,7 @@ void flow_action_cookie_destroy(struct flow_action_cookie *cookie);
>>  
>>  struct flow_action_entry {
>>  	enum flow_action_id		id;
>> +	enum flow_action_hw_stats_type	hw_stats_type;
>>  	action_destr			destructor;
>>  	void				*destructor_priv;
>>  	union {
>> @@ -228,6 +233,7 @@ struct flow_action_entry {
>>  };
>>  
>>  struct flow_action {
>> +	bool				mixed_hw_stats_types;
>
>Why do you want to place this built-in into the struct flow_action as
>a boolean?

Because it is convenient for the driver to know if multiple hw_stats_type
values are used for multiple actions.


>
>You can express the same thing through a new FLOW_ACTION_COUNTER.

I don't see how.


>I know tc has implicit counters in actions, in that case tc can just
>generate the counter right after the action.

I don't follow. Each action has a separate stats.


>
>Please, explain me why it would be a problem from the driver side to
>provide a separated counter action.

I don't see any point in doing that. The action itself implies that has
stats, you don't need a separate action for that for the flow_offload
abstraction layer. What you would end up with is:
counter_action1, actual_action1, counter_action2, actual_action2,...

What is the point of that?