Hello,
I'm getting a race in stmmac coalesce timer and the
napi_schedule() interrupt and I'm asking for advice. Currently,
we are scheduling NAPI in coalesce timer but this leads to
stmmac_tx_clean() deadlock because this function tries to acquire
queue lock.
I find that this is not expected because only one instance of
NAPI should run at same time so I was wondering if it is possible
that xmit() callback is causing the deadlock ?
BTW, this is solved by:
- Directly call stmmac_tx_clean() in timer function AND
- Use netif_tx_trylock() in stmmac_tx_clean(). Then, if queue
is already locked we re-arm coalesce timer or reschedule NAPI.
This is easily reproducible in an ARM board with 8 core running
at 100MHz each.
Thanks and Best Regards,
Jose Miguel Abreu
