[dpdk-dev] [PATCH] examples/bond: wait for slaves to become active

[Chas Williams]

On 11/28/2018 08:48 AM, Radu Nicolau wrote:
> Hi
> 
> 
> On 11/28/2018 11:08 AM, Ferruh Yigit wrote:
>> On 11/14/2018 12:19 PM, Radu Nicolau wrote:
>>> Do not start the packet processing threads until all configured
>>> slaves become active.
>> Hi Radu,
>>
>> What happens if packet processing threads started before all slaves 
>> active? Exit
>> app, error, crash?
>>
>> So can we say this patch is fixing packet forwarding? (fix in title?)
>>
>> And do we know what break it, why this was not required previously but 
>> required
>> now? (Fixes line ?)
>  From what I see, the problem was always there: bond_ethdev_rx_burst 
> will cycle through slaves, but if called more times with no active 
> slaves the active slave index will point out of bounds, resulting in a 
> segfault.
> While this may require a better fix, this patch is an improvement even 
> if that fix comes - the configured slaves needs to be checked, and if 
> none became active there is no point going further.
> 
> in bond_ethdev_rx_burst:
> 
> slave_count = internals->active_slave_count;
> ...
>      if (++internals->active_slave == slave_count)
>          internals->active_slave = 0;
> slave_count is zero, the if() will never be true and active_slave will 
> be continuously incremented. It was not written to work with no active 
> slaves.

Just create another patch for the rx routines.  If the active_slave_count
is 0, there's nothing to do really.  It should just return and not
bother with any of the other work.

> 
>>
>> Thanks,
>> ferruh
>>
>>> Signed-off-by: Radu Nicolau <radu.nicolau at intel.com>
>>> ---
>>>   examples/bond/main.c | 15 +++++++++++++++
>>>   1 file changed, 15 insertions(+)
>>>
>>> diff --git a/examples/bond/main.c b/examples/bond/main.c
>>> index b282e68..6623cae 100644
>>> --- a/examples/bond/main.c
>>> +++ b/examples/bond/main.c
>>> @@ -220,6 +220,7 @@ bond_port_init(struct rte_mempool *mbuf_pool)
>>>       struct rte_eth_rxconf rxq_conf;
>>>       struct rte_eth_txconf txq_conf;
>>>       struct rte_eth_conf local_port_conf = port_conf;
>>> +    uint16_t wait_counter = 20;
>>>       retval = rte_eth_bond_create("net_bonding0", BONDING_MODE_ALB,
>>>               0 /*SOCKET_ID_ANY*/);
>>> @@ -274,6 +275,20 @@ bond_port_init(struct rte_mempool *mbuf_pool)
>>>       if (retval < 0)
>>>           rte_exit(retval, "Start port %d failed (res=%d)", 
>>> BOND_PORT, retval);
>>> +    printf("Waiting for slaves to become active...");
>>> +    while (wait_counter) {
>>> +        uint16_t act_slaves[16] = {0};
>>> +        if (rte_eth_bond_active_slaves_get(BOND_PORT, act_slaves, 
>>> 16) ==
>>> +                slaves_count) {
>>> +            printf("\n");
>>> +            break;
>>> +        }
>>> +        sleep(1);
>>> +        printf("...");
>>> +        if (--wait_counter == 0)
>>> +            rte_exit(-1, "\nFailed to activate slaves\n");
>>> +    }
>>> +
>>>       rte_eth_promiscuous_enable(BOND_PORT);
>>>       struct ether_addr addr;
>>>
>