Re: [dpdk-dev] Problem in configuring buffer size of a memory pool

[Bruce Richardson <bruce.richardson@intel.com>]

On Thu, Feb 09, 2017 at 12:08:54PM +0530, Karthikraj palanichamy wrote:
> Hi developers,
> 
> For /`rte_pktmbuf_pool_create()`, /I normally provide
> RTE_MBUF_DEFAULT_BUF_SIZE as the data room size.
> 
> I needed to change this dynamically based on the frame size to be
> transmitted.
> To transmit 80 bytes frames, I configured (80 +/RTE_PKTMBUF_HEADROOM/).
> There was no problem and transmission was successful.
> 
> Then I will do `rte_mempool_free()` and create mem pool again whenever
> needed.
> 
> So, my code flow is /create mempool -> transmit pkts -> free mempool/
> 
> When I do this for 3 to 5 times, I get segmentation fault in the
> transmission API of the PMD. - 'eth_igb_xmit_pkts' for igb PMD and
> 'ixgbe_xmit_pkts_vec()' for ixgbe PMD.
> 
> Thanks in advance for your help.
> 
I think you'll need to stop the transmit ports and possibly destroy and 
recreate the TX queues too. What may be happening is that packet buffers
are remaining on the TX ring after transmit, and then when being freed
to make room for new packet buffers to be transmitted, the mempool to
which they are to be freed no longer exists.

> Regards
> Karthik
> 
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/Bruce