[dpdk-dev] Multi-thread mempool usage

[Matteo Lanzuisi <m.lanzuisi@resi.it>]

Hi all,

recently I began using "dpdk-17.11-11.el7.x86_64" rpm (RedHat rpm) on 
RedHat 7.5 kernel 3.10.0-862.6.3.el7.x86_64 as a porting of an 
application from RH6 to RH7. On RH6 I used dpdk-2.2.0.

This application is made up by one or more threads (each one on a 
different logical core) reading packets from i40e interfaces.

Each thread can call the following code lines when receiving a specific 
packet:

RTE_LCORE_FOREACH(lcore_id)
{
         result = 
rte_mempool_get(cea_main_lcore_conf[lcore_id].de_conf.cmd_pool, (VOID_P 
*) &new_work);        // mempools are created one for each logical core
         if (((uint64_t)(new_work)) < 0x7f0000000000)
             printf("Result %d, lcore di partenza %u, lcore di ricezione 
%u, pointer %p\n", result, rte_lcore_id(), lcore_id, new_work);    // 
debug print, on my server it should never happen but with multi-thread 
happens always on the last logical core!!!!
         if (result == 0)
         {
             new_work->command = command; // usage of the memory gotten 
from the mempool... <<<<<- here is where the application crashes!!!!
             result = 
rte_ring_enqueue(cea_main_lcore_conf[lcore_id].de_conf.cmd_ring, 
(VOID_P) new_work);    // enqueues the gotten buffer on the rings of all 
lcores
             // check on result value ...
         }
         else
         {
             // do something if result != 0 ...
         }
}

This code worked perfectly (never had an issue) on dpdk-2.2.0, while if 
I use more than 1 thread doing these operations on dpdk-17.11 it happens 
that after some times the "new_work" pointer is not a good one, and the 
application crashes when using that pointer.

It seems that these lines cannot be used by more than one thread 
simultaneously. I also used many 2017 and 2018 dpdk versions without 
success.

Is this code possible on the new dpdk versions? Or have I to change my 
application so that this code is called just by one lcore at a time?

Matteo