On Wed, Oct 9, 2024 at 2:56 AM Joe Damato <jdamato@xxxxxxxxxx> wrote: > > Add a persistent NAPI config area for NAPI configuration to the core. > Drivers opt-in to setting the persistent config for a NAPI by passing an > index when calling netif_napi_add_config. > > napi_config is allocated in alloc_netdev_mqs, freed in free_netdev > (after the NAPIs are deleted). > > Drivers which call netif_napi_add_config will have persistent per-NAPI > settings: NAPI IDs, gro_flush_timeout, and defer_hard_irq settings. > > Per-NAPI settings are saved in napi_disable and restored in napi_enable. > > Co-developed-by: Martin Karsten <mkarsten@xxxxxxxxxxxx> > Signed-off-by: Martin Karsten <mkarsten@xxxxxxxxxxxx> > Signed-off-by: Joe Damato <jdamato@xxxxxxxxxx> > --- > .../networking/net_cachelines/net_device.rst | 1 + > include/linux/netdevice.h | 36 ++++++++- > net/core/dev.c | 79 +++++++++++++++++-- > net/core/dev.h | 12 +++ > 4 files changed, 118 insertions(+), 10 deletions(-) > > diff --git a/Documentation/networking/net_cachelines/net_device.rst b/Documentation/networking/net_cachelines/net_device.rst > index 3ab663b6cf16..9d86720cb722 100644 > --- a/Documentation/networking/net_cachelines/net_device.rst > +++ b/Documentation/networking/net_cachelines/net_device.rst > @@ -183,5 +183,6 @@ struct_dpll_pin* dpll_pin > struct hlist_head page_pools > struct dim_irq_moder* irq_moder > u64 max_pacing_offload_horizon > +struct_napi_config* napi_config > unsigned_long gro_flush_timeout > u32 napi_defer_hard_irqs > diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h > index 4239a4a9d295..b65a901ab4e7 100644 > --- a/include/linux/netdevice.h > +++ b/include/linux/netdevice.h > @@ -342,6 +342,15 @@ struct gro_list { > */ > #define GRO_HASH_BUCKETS 8 > > +/* > + * Structure for per-NAPI config > + */ > +struct napi_config { > + u64 gro_flush_timeout; > + u32 defer_hard_irqs; > + unsigned int napi_id; > +}; > + > /* > * Structure for NAPI scheduling similar to tasklet but with weighting > */ > @@ -379,6 +388,8 @@ struct napi_struct { > struct list_head dev_list; > struct hlist_node napi_hash_node; > int irq; > + int index; > + struct napi_config *config; > }; > > enum { > @@ -1860,9 +1871,6 @@ enum netdev_reg_state { > * allocated at register_netdev() time > * @real_num_rx_queues: Number of RX queues currently active in device > * @xdp_prog: XDP sockets filter program pointer > - * @gro_flush_timeout: timeout for GRO layer in NAPI > - * @napi_defer_hard_irqs: If not zero, provides a counter that would > - * allow to avoid NIC hard IRQ, on busy queues. > * > * @rx_handler: handler for received packets > * @rx_handler_data: XXX: need comments on this one > @@ -2012,6 +2020,11 @@ enum netdev_reg_state { > * where the clock is recovered. > * > * @max_pacing_offload_horizon: max EDT offload horizon in nsec. > + * @napi_config: An array of napi_config structures containing per-NAPI > + * settings. > + * @gro_flush_timeout: timeout for GRO layer in NAPI > + * @napi_defer_hard_irqs: If not zero, provides a counter that would > + * allow to avoid NIC hard IRQ, on busy queues. > * > * FIXME: cleanup struct net_device such that network protocol info > * moves out. > @@ -2405,6 +2418,7 @@ struct net_device { > struct dim_irq_moder *irq_moder; > > u64 max_pacing_offload_horizon; > + struct napi_config *napi_config; > unsigned long gro_flush_timeout; > u32 napi_defer_hard_irqs; > > @@ -2657,6 +2671,22 @@ netif_napi_add_tx_weight(struct net_device *dev, > netif_napi_add_weight(dev, napi, poll, weight); > } > > +/** > + * netif_napi_add_config - initialize a NAPI context with persistent config > + * @dev: network device > + * @napi: NAPI context > + * @poll: polling function > + * @index: the NAPI index > + */ > +static inline void > +netif_napi_add_config(struct net_device *dev, struct napi_struct *napi, > + int (*poll)(struct napi_struct *, int), int index) > +{ > + napi->index = index; > + napi->config = &dev->napi_config[index]; > + netif_napi_add_weight(dev, napi, poll, NAPI_POLL_WEIGHT); > +} > + > /** > * netif_napi_add_tx() - initialize a NAPI context to be used for Tx only > * @dev: network device > diff --git a/net/core/dev.c b/net/core/dev.c > index fca2295f4d95..bd87232f7b37 100644 > --- a/net/core/dev.c > +++ b/net/core/dev.c > @@ -6503,6 +6503,22 @@ EXPORT_SYMBOL(napi_busy_loop); > > #endif /* CONFIG_NET_RX_BUSY_POLL */ > > +static void __napi_hash_add_with_id(struct napi_struct *napi, > + unsigned int napi_id) > +{ > + napi->napi_id = napi_id; > + hlist_add_head_rcu(&napi->napi_hash_node, > + &napi_hash[napi->napi_id % HASH_SIZE(napi_hash)]); > +} > + > +static void napi_hash_add_with_id(struct napi_struct *napi, > + unsigned int napi_id) > +{ > + spin_lock(&napi_hash_lock); > + __napi_hash_add_with_id(napi, napi_id); Hmmm... there is no check if 'napi_id' is already used and hashed. I would add WARN_ON_ONCE(napi_by_id(napi_id)); > + spin_unlock(&napi_hash_lock); > +} > + > static void napi_hash_add(struct napi_struct *napi) > { > if (test_bit(NAPI_STATE_NO_BUSY_POLL, &napi->state)) > @@ -6515,10 +6531,8 @@ static void napi_hash_add(struct napi_struct *napi) > if (unlikely(++napi_gen_id < MIN_NAPI_ID)) > napi_gen_id = MIN_NAPI_ID; > } while (napi_by_id(napi_gen_id)); > - napi->napi_id = napi_gen_id; > > - hlist_add_head_rcu(&napi->napi_hash_node, > - &napi_hash[napi->napi_id % HASH_SIZE(napi_hash)]); > + __napi_hash_add_with_id(napi, napi_gen_id); > > spin_unlock(&napi_hash_lock); > } >