[dpdk-stable] [PATCH v5 04/15] distributor: handle worker shutdown in burst mode

[David Hunt]

On 8/10/2020 6:23 AM, Lukasz Wojciechowski wrote:
> The burst version of distributor implementation was missing proper
> handling of worker shutdown. A worker processing packets received
> from distributor can call rte_distributor_return_pkt() function
> informing distributor that it want no more packets. Further calls to
> rte_distributor_request_pkt() or rte_distributor_get_pkt() however
> should inform distributor that new packets are requested again.
>
> Lack of the proper implementation has caused that even after worker
> informed about returning last packets, new packets were still sent
> from distributor causing deadlocks as no one could get them on worker
> side.
>
> This patch adds handling shutdown of the worker in following way:
> 1) It fixes usage of RTE_DISTRIB_VALID_BUF handshake flag. This flag
> was formerly unused in burst implementation and now it is used
> for marking valid packets in retptr64 replacing invalid use
> of RTE_DISTRIB_RETURN_BUF flag.
> 2) Uses RTE_DISTRIB_RETURN_BUF as a worker to distributor handshake
> in retptr64 to indicate that worker has shutdown.
> 3) Worker that shuts down blocks also bufptr for itself with
> RTE_DISTRIB_RETURN_BUF flag allowing distributor to retrieve any
> in flight packets.
> 4) When distributor receives information about shutdown of a worker,
> it: marks worker as not active; retrieves any in flight and backlog
> packets and process them to different workers; unlocks bufptr64
> by clearing RTE_DISTRIB_RETURN_BUF flag and allowing use in
> the future if worker requests any new packages.
> 5) Do not allow to: send or add to backlog any packets for not
> active workers. Such workers are also ignored if matched.
> 6) Adjust calls to handle_returns() and tags matching procedure
> to react for possible activation deactivation of workers.
>
> Fixes: 775003ad2f96 ("distributor: add new burst-capable library")
> Cc: david.hunt at intel.com
> Cc: stable at dpdk.org
>
> Signed-off-by: Lukasz Wojciechowski <l.wojciechow at partner.samsung.com>
> ---


Hi Lukasz,

    I spent the most amount of time going through this particular patch, 
and it looks good to me (even the bit where rte_distributor_process is 
called recursively) :)

I'll try and get some time to run through some more testing, but for now:

Acked-by: David Hunt <david.hunt at intel.com>