Re: [dpdk-dev] [PATCH] examples/ipsec-secgw: fix session mempool initialisation

["Medvedkin, Vladimir" <vladimir.medvedkin@intel.com>]

Hi Akhil,

On 28/10/2020 12:30, Akhil Goyal wrote:
> Hi Vladimir,
> 
>> -----Original Message-----
>> From: Vladimir Medvedkin <vladimir.medvedkin@intel.com>
>> Sent: Tuesday, October 27, 2020 7:34 PM
>> To: dev@dpdk.org
>> Cc: Akhil Goyal <akhil.goyal@nxp.com>; Radu Nicolau <radu.nicolau@intel.com>
>> Subject: [PATCH] examples/ipsec-secgw: fix session mempool initialisation
>>
>> Creation of a session mempool may fail in the case of a single lcore
>> and a low number of SA.
>>
> 
> I am not able to understand the reason why the number need to be increased.
> Could you please explain?
> 

Sure. Starting ipsec-secgw with 4 configured SA with single lcore fails 
with:

CRYPTODEV: rte_cryptodev_sym_session_pool_create() line 1420: 
rte_cryptodev_sym_session_pool_create(name=sess_mp_0) failed, rte_errno=22

In case when there is only one lcore and number of configures SA less 
then (0.5 * CDEV_MP_CACHE_SZ) then creation of the mempool fails with 
EINVAL. This is because the number of requested items is less than 
(cache size * 1.5)

from rte_mempool_create_empty():

         /* asked cache too big */
         if (cache_size > RTE_MEMPOOL_CACHE_MAX_SIZE ||
             CALC_CACHE_FLUSHTHRESH(cache_size) > n) {
                 rte_errno = EINVAL;
                 return NULL;
         }

, where n is nb_sess and CALC_CACHE_FLUSHTHRESH(cache_size) is just (1.5 
* cache_size). This was mentioned in rte_mempool_create() documentation:
@param cache_size
...
  *   This argument must be lower or equal to
  *   RTE_MEMPOOL_CACHE_MAX_SIZE and n / 1.5.
...

Before https://patches.dpdk.org/patch/81245/ there was no such a problem 
due to multiplying nb_sess by 2.


>> Fixes: e30b2833c47c ("security: update session create API")
>> Cc: akhil.goyal@nxp.com
>>
>> Signed-off-by: Vladimir Medvedkin <vladimir.medvedkin@intel.com>
>> ---
>>   examples/ipsec-secgw/ipsec-secgw.c | 5 +++++
>>   1 file changed, 5 insertions(+)
>>
>> diff --git a/examples/ipsec-secgw/ipsec-secgw.c b/examples/ipsec-
>> secgw/ipsec-secgw.c
>> index 2219148..935829e 100644
>> --- a/examples/ipsec-secgw/ipsec-secgw.c
>> +++ b/examples/ipsec-secgw/ipsec-secgw.c
>> @@ -65,6 +65,7 @@ volatile bool force_quit;
>>   #define CDEV_QUEUE_DESC 2048
>>   #define CDEV_MAP_ENTRIES 16384
>>   #define CDEV_MP_CACHE_SZ 64
>> +#define CDEV_MP_CACHE_MULTIPLIER 1.5 /* from rte_mempool.c */
>>   #define MAX_QUEUE_PAIRS 1
>>
>>   #define BURST_TX_DRAIN_US 100 /* TX drain every ~100us */
>> @@ -2350,6 +2351,8 @@ session_pool_init(struct socket_ctx *ctx, int32_t
>> socket_id, size_t sess_sz)
>>   			"sess_mp_%u", socket_id);
>>   	nb_sess = (get_nb_crypto_sessions() + CDEV_MP_CACHE_SZ *
>>   		rte_lcore_count());
>> +	nb_sess = RTE_MAX(nb_sess, CDEV_MP_CACHE_SZ *
>> +			CDEV_MP_CACHE_MULTIPLIER);
>>   	sess_mp = rte_cryptodev_sym_session_pool_create(
>>   			mp_name, nb_sess, sess_sz, CDEV_MP_CACHE_SZ, 0,
>>   			socket_id);
>> @@ -2374,6 +2377,8 @@ session_priv_pool_init(struct socket_ctx *ctx, int32_t
>> socket_id,
>>   			"sess_mp_priv_%u", socket_id);
>>   	nb_sess = (get_nb_crypto_sessions() + CDEV_MP_CACHE_SZ *
>>   		rte_lcore_count());
>> +	nb_sess = RTE_MAX(nb_sess, CDEV_MP_CACHE_SZ *
>> +			CDEV_MP_CACHE_MULTIPLIER);
>>   	sess_mp = rte_mempool_create(mp_name,
>>   			nb_sess,
>>   			sess_sz,
>> --
>> 2.7.4
> 

-- 
Regards,
Vladimir