Re: [dpdk-dev] [PATCH] Function __mempool_get_bulk() returns wrong count.

["Wiles, Roger Keith" <keith.wiles@windriver.com>]

On Sep 28, 2014, at 5:25 PM, Ananyev, Konstantin <konstantin.ananyev@intel.com> wrote:

> 
> 
>> -----Original Message-----
>> From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Wiles, Roger Keith
>> Sent: Saturday, September 27, 2014 7:42 PM
>> To: <dev@dpdk.org>
>> Subject: [dpdk-dev] [PATCH] Function __mempool_get_bulk() returns wrong count.
>> 
>> 
>> When __mempool_get_bulk() grabs entries from the cache it
>> returns zero instead of the number of entries obtained. Plus
>> the stats were increased by the wrong count of objects.
>> 
>> Signed-off-by: Keith Wiles <keith.wiles@windriver.com>
>> ---
>> lib/librte_mempool/rte_mempool.h | 6 +++---
>> 1 file changed, 3 insertions(+), 3 deletions(-)
>> 
>> diff --git a/lib/librte_mempool/rte_mempool.h b/lib/librte_mempool/rte_mempool.h
>> index 299d4d7..6750e78 100644
>> --- a/lib/librte_mempool/rte_mempool.h
>> +++ b/lib/librte_mempool/rte_mempool.h
>> @@ -988,9 +988,9 @@ __mempool_get_bulk(struct rte_mempool *mp, void **obj_table,
>> 
>>        cache->len -= n;
>> 
>> -       __MEMPOOL_STAT_ADD(mp, get_success, n_orig);
>> +       __MEMPOOL_STAT_ADD(mp, get_success, n);
> 
> As I can see n == n_orig.
> We can completely remove n_orig, but from other side - I don't see any harm here.

In the RFC patch I sent I remove n_orig.
> 
>> 
>> -       return 0;
>> +       return n;
> 
> As I can see, __mempool_get_bulk supposed to return 0,
> if all n objects were allocated from mbuf, or a negative error code otherwise.
> Check all usages of __mempool_get_bulk(), plus the fact that it does below:
> ret = rte_ring_mc_dequeue_bulk(mp->ring, obj_table, n);
> and rte_ring_mc_dequeue_bulk() is just wrapper for __rte_ring_mc_do_dequeue(..., n, RTE_RING_QUEUE_FIXED);
> I.e. - either allocate all n objects, or return with failure.
> So, yes we should return 0 here.
> The only thing that probably needs to be done here: fix the comments.
> Instead of:
> - >=0: Success; number of objects supplied.
> Something like:
> - 0: Success; n objects supplied.
> 
>> 
>> ring_dequeue:
>> #endif /* RTE_MEMPOOL_CACHE_MAX_SIZE > 0 */
>> @@ -1004,7 +1004,7 @@ ring_dequeue:
>>        if (ret < 0)
>>                __MEMPOOL_STAT_ADD(mp, get_fail, n_orig);
>>        else
>> -               __MEMPOOL_STAT_ADD(mp, get_success, n_orig);
>> +               __MEMPOOL_STAT_ADD(mp, get_success, ret);
> 
> That seems incorrect tom me.
> ret would be either 0 on success, or negative error value.

Notice ‘if (ret < 0)’ above so ret can not be negative in this case only zero or positive.
> 
> Konstantin
> 
> 
>> 
>>        return ret;
>> }
>> --
>> 2.1.0Keith Wiles, Principal Technologist with CTO office, Wind River mobile 972-213-5533
> 
> 
> As I can see

Keith Wiles, Principal Technologist with CTO office, Wind River mobile 972-213-5533