> -----Original Message-----
> From: Stephen Hemminger <[email protected]>
> Sent: Friday, May 29, 2026 11:35 PM
> To: Wei Hu <[email protected]>
> Cc: [email protected]; Long Li <[email protected]>; Wei Hu
> <[email protected]>
> Subject: [EXTERNAL] Re: [PATCH v5 1/1] net/mana: add device reset support
>
> On Fri, 29 May 2026 07:26:48 -0700
> Wei Hu <[email protected]> wrote:
>
> > diff --git a/drivers/net/mana/mana.c b/drivers/net/mana/mana.c index
> > 67396cda1f..89e45c53c1 100644
> > --- a/drivers/net/mana/mana.c
> > +++ b/drivers/net/mana/mana.c
> > @@ -13,7 +13,10 @@
> > #include <ethdev_pci.h>
> > #include <rte_kvargs.h>
> > #include <rte_eal_paging.h>
> > +#include <rte_alarm.h>
> > #include <rte_pci.h>
> > +#include <rte_rcu_qsbr.h>
> > +#include <rte_lock_annotations.h>
> >
> > #include <infiniband/verbs.h>
> > #include <infiniband/manadv.h>
> > @@ -103,6 +106,23 @@ mana_dev_configure(struct rte_eth_dev *dev)
> > RTE_ETH_RX_OFFLOAD_VLAN_STRIP);
> >
> > priv->num_queues = dev->data->nb_rx_queues;
> > + DRV_LOG(DEBUG, "priv %p, port %u, dev port %u, num_queues: %u",
> > + priv, priv->port_id, priv->dev_port, priv->num_queues);
> > +
> > + /*
> > + * Register data path thread IDs (rx and tx) with the RCU
> > + * quiescent state variable for device state synchronization.
> > + */
> > + for (int i = 0; i < 2 * priv->num_queues; i++) {
> > + if (rte_rcu_qsbr_thread_register(priv->dev_state_qsv, i) != 0) {
> > + DRV_LOG(ERR, "Failed to register rcu qsv thread %d of
> total %d",
> > + i, 2 * priv->num_queues - 1);
> > + return -EINVAL;
> > + }
> > + DRV_LOG(DEBUG,
> > + "Register thread 0x%x for priv %p, port %u",
> > + i, priv, priv->port_id);
> > + }
> >
>
> If device driver now has dependency on RCU you need to update meson.build
> to show that. No other driver does this. Creating threads in driver is
> discouraged because it can lead to other problems in applications.
>
> If possible, I would figure out how to manage reset without creating a thread
> per-queue. Or at least one control thread and use epoll() and eventfd's.
Update in meson.build was included in the patch.
I didn't create a thread per-queue. I just added a tid for each queue and use it
as an identifier in rte_rcu_qsbr_thread_register(). Calling
rte_rcu_qsbr_thread_register() doesn't create any additional thread. It just let
the rcu_qsbr know how many tx and rx threads it should expect to be offline
before
device resetting can proceed.
Wei
