Re: [dpdk-dev] net/ixgbe: ixgbe_dev_link_update_share() leaks memory and memory mappings due to not cleaning up pthreads

[Martin Weiser <martin.weiser@allegro-packets.com>]

Hi,

I should have mentioned that our findings apply to DPDK 20.02. I can see
in master that this since has been reworked to use rte_eal_alarm_set()
instead of using a thread.
But maybe this should be addressed in stable?

Best regards,
Martin Weiser


Am 09.04.20 um 12:30 schrieb Martin Weiser:
> Hi,
>
> we recently discovered that our application was not able to create new
> threads or perform mmaps after some time.
> With some digging we identified the function
> ixgbe_dev_link_update_share() to be the reason for this behavior.
>
> In the patch "net/ixgbe: fix blocking system events"
> (819d0d1d57f17aa40321648e99a50b49adc7bdf6) a thread is introduced to
> run ixgbe_dev_setup_link_thread_handler().
> Unfortunately this thread is not detached and just joined (the very
> last one spawned that is) through ixgbe_dev_cancel_link_thread() upon
> interface start/stop.
>
> When an application repeatedly calls e.g. rte_eth_link_get_nowait() on
> an ixgbe interface with no link this causes a lot of pthreads never to
> be cleaned up.
> Since each thread holds a mmap to the stack this can quite quickly
> exhaust the allowed number of memory mappings for the process.
>
> Best regards,
> Martin Weiser
>