Re: [dpdk-dev] [PATCH v2] app/testpmd: support age shared action context

[Ferruh Yigit <ferruh.yigit@intel.com>]

On 11/7/2020 5:30 PM, Matan Azrad wrote:
> Hi Ferruh
> 
> From: Ferruh Yigit
>> On 11/5/2020 9:32 PM, Matan Azrad wrote:
>>> When an age action becomes aged-out the rte_flow_get_aged_flows should
>>> return the action context supplied by the configuration structure.
>>>
>>> In case the age action created by the shared action API, the shared
>>> action context of the Testpmd application was not set.
>>>
>>> In addition, the application handler of the contexts returned by the
>>> rte_flow_get_aged_flows API didn't consider the fact that the action
>>> could be set by the shared action API and considered it as regular
>>> flow context.
>>>
>>> This caused a crash in Testpmd when the context is parsed.
>>>
>>> This patch set context type in the flow and shared action context and
>>> uses it to parse the aged-out contexts correctly.
>>>
>>> Signed-off-by: Matan Azrad <matan@nvidia.com>
>>> Acked-by: Dekel Peled <dekelp@nvidia.com>
>>> ---
>>>    app/test-pmd/config.c  | 119 ++++++++++++++++++++++++++++++++++-------
>> --------
>>>    app/test-pmd/testpmd.h |   5 +++
>>>    2 files changed, 87 insertions(+), 37 deletions(-)
>>>
>>> diff --git a/app/test-pmd/config.c b/app/test-pmd/config.c index
>>> 755d1df..00a7dd1 100644
>>> --- a/app/test-pmd/config.c
>>> +++ b/app/test-pmd/config.c
>>> @@ -1763,6 +1763,33 @@ void port_flow_tunnel_create(portid_t port_id,
>> const struct tunnel_ops *ops)
>>>        }
>>>    }
>>>
>>> +#define AGE_ACTION_TYPE_MASK 0x3u
>>> +
>>> +static void
>>> +set_age_action_context(void **ctx, enum action_age_context_type type,
>>> +void *obj) {
>>> +     uintptr_t value = (uintptr_t)obj;
>>> +
>>> +     /*
>>> +      * obj is allocated by malloc\calloc which must return an address
>>> +      * aligned to 8.
>>> +      * Use the last 2 bits for the age context type.
>>> +      */
>>> +     value |= (uintptr_t)type & AGE_ACTION_TYPE_MASK;
>>> +     *ctx = (void *)value;
>>
>> Thanks Matan, I think this is much clear. But I though the 'id' will be used, not
>> the pointer itself, like "uintptr_t value = id | (type * MASK)"
>> OR the address pointer and type seems error prone, although you comment
>> you rely on the alignment.
> 
> I understand your concern, that's why the context value management is wrapped well by dedicated functions for set and parse.
> Also it's very optimized way for memory and time especially when we are talking about big scale(see below).
> 
>> The testpmd usage also kind of sample usage for the applications, I am for not
>> suggesting this for the user applications.
> 
> 
>> Reserving the two bit of the 'id' reduces the usable 'id' to 30 bits, but it looks
>> still big enough, what do you think?
> 
> 
> Yes, it is big enough.
> The problem with the id is the latency to get the pointer from it.
> Since both the flows and the shared actions are saved in a list we need to traverse all the list in order to get the pointer and the needed information.
> 

Using 'id' was your idea.

OK, what about back to previous suggestion, adding a new data struct for both 
pointers and type?
Your concern there was the memory consumption, yes although it will require more 
memory the amount is not unreasonable.