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Miller" , Eric Dumazet , Paolo Abeni , Jonathan Corbet , Jiri Pirko , Sebastian Andrzej Siewior , Lorenzo Bianconi , David Ahern , Johannes Berg , linux-doc@vger.kernel.org (open list:DOCUMENTATION), linux-kernel@vger.kernel.org (open list) Subject: [RFC net-next v3 5/9] net: napi: Add napi_config Date: Thu, 12 Sep 2024 10:07:13 +0000 Message-Id: <20240912100738.16567-6-jdamato@fastly.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20240912100738.16567-1-jdamato@fastly.com> References: <20240912100738.16567-1-jdamato@fastly.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Add a persistent NAPI config area for NAPI configuration to the core. Drivers opt-in to setting the storage for a NAPI by passing an index when calling netif_napi_add_storage. napi_config is allocated in alloc_netdev_mqs, freed in free_netdev (after the NAPIs are deleted), and set to 0 when napi_enable is called. Drivers which implement call netif_napi_add_storage will have persistent NAPI IDs. Signed-off-by: Joe Damato --- .../networking/net_cachelines/net_device.rst | 1 + include/linux/netdevice.h | 34 +++++++++ net/core/dev.c | 74 +++++++++++++++++-- net/core/dev.h | 12 +++ 4 files changed, 113 insertions(+), 8 deletions(-) diff --git a/Documentation/networking/net_cachelines/net_device.rst b/Docum= entation/networking/net_cachelines/net_device.rst index 3d02ae79c850..11d659051f5e 100644 --- a/Documentation/networking/net_cachelines/net_device.rst +++ b/Documentation/networking/net_cachelines/net_device.rst @@ -183,3 +183,4 @@ struct hlist_head page_pools struct dim_irq_moder* irq_moder unsigned_long gro_flush_timeout u32 napi_defer_hard_irqs +struct napi_config* napi_config diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index 3e07ab8e0295..08afc96179f9 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -342,6 +342,15 @@ struct gro_list { */ #define GRO_HASH_BUCKETS 8 =20 +/* + * Structure for per-NAPI storage + */ +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 { int irq; unsigned long gro_flush_timeout; u32 defer_hard_irqs; + int index; + struct napi_config *config; }; =20 enum { @@ -2011,6 +2022,9 @@ enum netdev_reg_state { * @dpll_pin: Pointer to the SyncE source pin of a DPLL subsystem, * where the clock is recovered. * + * @napi_config: An array of napi_config structures containing per-NAPI + * settings. + * * FIXME: cleanup struct net_device such that network protocol info * moves out. */ @@ -2400,6 +2414,7 @@ struct net_device { struct dim_irq_moder *irq_moder; unsigned long gro_flush_timeout; u32 napi_defer_hard_irqs; + struct napi_config *napi_config; =20 u8 priv[] ____cacheline_aligned __counted_by(priv_len); @@ -2650,6 +2665,23 @@ netif_napi_add_tx_weight(struct net_device *dev, netif_napi_add_weight(dev, napi, poll, weight); } =20 +/** + * netif_napi_add_storage - initialize a NAPI context and set storage area + * @dev: network device + * @napi: NAPI context + * @poll: polling function + * @weight: the poll weight of this NAPI + * @index: the NAPI index + */ +static inline void +netif_napi_add_storage(struct net_device *dev, struct napi_struct *napi, + int (*poll)(struct napi_struct *, int), int index) +{ + napi->index =3D index; + napi->config =3D &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 @@ -2685,6 +2717,8 @@ void __netif_napi_del(struct napi_struct *napi); */ static inline void netif_napi_del(struct napi_struct *napi) { + napi->config =3D NULL; + napi->index =3D -1; __netif_napi_del(napi); synchronize_net(); } diff --git a/net/core/dev.c b/net/core/dev.c index f2fd503516de..ca2227d0b8ed 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -6493,6 +6493,18 @@ EXPORT_SYMBOL(napi_busy_loop); =20 #endif /* CONFIG_NET_RX_BUSY_POLL */ =20 +static void napi_hash_add_with_id(struct napi_struct *napi, unsigned int n= api_id) +{ + spin_lock(&napi_hash_lock); + + napi->napi_id =3D napi_id; + + hlist_add_head_rcu(&napi->napi_hash_node, + &napi_hash[napi->napi_id % HASH_SIZE(napi_hash)]); + + spin_unlock(&napi_hash_lock); +} + static void napi_hash_add(struct napi_struct *napi) { if (test_bit(NAPI_STATE_NO_BUSY_POLL, &napi->state)) @@ -6505,12 +6517,13 @@ static void napi_hash_add(struct napi_struct *napi) if (unlikely(++napi_gen_id < MIN_NAPI_ID)) napi_gen_id =3D MIN_NAPI_ID; } while (napi_by_id(napi_gen_id)); - napi->napi_id =3D napi_gen_id; - - hlist_add_head_rcu(&napi->napi_hash_node, - &napi_hash[napi->napi_id % HASH_SIZE(napi_hash)]); =20 spin_unlock(&napi_hash_lock); + + napi_hash_add_with_id(napi, napi_gen_id); + + if (napi->config) + napi->config->napi_id =3D napi_gen_id; } =20 /* Warning : caller is responsible to make sure rcu grace period @@ -6631,6 +6644,21 @@ void netif_queue_set_napi(struct net_device *dev, un= signed int queue_index, } EXPORT_SYMBOL(netif_queue_set_napi); =20 +static void napi_restore_config(struct napi_struct *n) +{ + n->defer_hard_irqs =3D n->config->defer_hard_irqs; + n->gro_flush_timeout =3D n->config->gro_flush_timeout; + napi_hash_add_with_id(n, n->config->napi_id); +} + +static void napi_save_config(struct napi_struct *n) +{ + n->config->defer_hard_irqs =3D n->defer_hard_irqs; + n->config->gro_flush_timeout =3D n->gro_flush_timeout; + n->config->napi_id =3D n->napi_id; + napi_hash_del(n); +} + void netif_napi_add_weight(struct net_device *dev, struct napi_struct *nap= i, int (*poll)(struct napi_struct *, int), int weight) { @@ -6641,8 +6669,6 @@ void netif_napi_add_weight(struct net_device *dev, st= ruct napi_struct *napi, INIT_HLIST_NODE(&napi->napi_hash_node); hrtimer_init(&napi->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_PINNED); napi->timer.function =3D napi_watchdog; - napi_set_defer_hard_irqs(napi, READ_ONCE(dev->napi_defer_hard_irqs)); - napi_set_gro_flush_timeout(napi, READ_ONCE(dev->gro_flush_timeout)); init_gro_hash(napi); napi->skb =3D NULL; INIT_LIST_HEAD(&napi->rx_list); @@ -6660,7 +6686,15 @@ void netif_napi_add_weight(struct net_device *dev, s= truct napi_struct *napi, set_bit(NAPI_STATE_SCHED, &napi->state); set_bit(NAPI_STATE_NPSVC, &napi->state); list_add_rcu(&napi->dev_list, &dev->napi_list); - napi_hash_add(napi); + /* if there is no config associated with this NAPI, generate a fresh + * NAPI ID and hash it. Otherwise, settings will be restored in napi_enab= le. + */ + if (!napi->config || (napi->config && !napi->config->napi_id)) { + napi_hash_add(napi); + napi_set_defer_hard_irqs(napi, READ_ONCE(dev->napi_defer_hard_irqs)); + napi_set_gro_flush_timeout(napi, READ_ONCE(dev->gro_flush_timeout)); + } + napi_get_frags_check(napi); /* Create kthread for this napi if dev->threaded is set. * Clear dev->threaded if kthread creation failed so that @@ -6692,6 +6726,9 @@ void napi_disable(struct napi_struct *n) =20 hrtimer_cancel(&n->timer); =20 + if (n->config) + napi_save_config(n); + clear_bit(NAPI_STATE_DISABLE, &n->state); } EXPORT_SYMBOL(napi_disable); @@ -6714,6 +6751,9 @@ void napi_enable(struct napi_struct *n) if (n->dev->threaded && n->thread) new |=3D NAPIF_STATE_THREADED; } while (!try_cmpxchg(&n->state, &val, new)); + + if (n->config) + napi_restore_config(n); } EXPORT_SYMBOL(napi_enable); =20 @@ -6736,7 +6776,13 @@ void __netif_napi_del(struct napi_struct *napi) if (!test_and_clear_bit(NAPI_STATE_LISTED, &napi->state)) return; =20 - napi_hash_del(napi); + if (!napi->config) { + napi_hash_del(napi); + } else { + napi->index =3D -1; + napi->config =3D NULL; + } + list_del_rcu(&napi->dev_list); napi_free_frags(napi); =20 @@ -11049,6 +11095,8 @@ struct net_device *alloc_netdev_mqs(int sizeof_priv= , const char *name, unsigned int txqs, unsigned int rxqs) { struct net_device *dev; + size_t napi_config_sz; + unsigned int maxqs; =20 BUG_ON(strlen(name) >=3D sizeof(dev->name)); =20 @@ -11062,6 +11110,9 @@ struct net_device *alloc_netdev_mqs(int sizeof_priv= , const char *name, return NULL; } =20 + WARN_ON_ONCE(txqs !=3D rxqs); + maxqs =3D max(txqs, rxqs); + dev =3D kvzalloc(struct_size(dev, priv, sizeof_priv), GFP_KERNEL_ACCOUNT | __GFP_RETRY_MAYFAIL); if (!dev) @@ -11136,6 +11187,11 @@ struct net_device *alloc_netdev_mqs(int sizeof_pri= v, const char *name, if (!dev->ethtool) goto free_all; =20 + napi_config_sz =3D array_size(maxqs, sizeof(*dev->napi_config)); + dev->napi_config =3D kvzalloc(napi_config_sz, GFP_KERNEL_ACCOUNT); + if (!dev->napi_config) + goto free_all; + strscpy(dev->name, name); dev->name_assign_type =3D name_assign_type; dev->group =3D INIT_NETDEV_GROUP; @@ -11197,6 +11253,8 @@ void free_netdev(struct net_device *dev) list_for_each_entry_safe(p, n, &dev->napi_list, dev_list) netif_napi_del(p); =20 + kvfree(dev->napi_config); + ref_tracker_dir_exit(&dev->refcnt_tracker); #ifdef CONFIG_PCPU_DEV_REFCNT free_percpu(dev->pcpu_refcnt); diff --git a/net/core/dev.h b/net/core/dev.h index a9d5f678564a..9eb3f559275c 100644 --- a/net/core/dev.h +++ b/net/core/dev.h @@ -167,11 +167,17 @@ static inline void napi_set_defer_hard_irqs(struct na= pi_struct *n, u32 defer) static inline void netdev_set_defer_hard_irqs(struct net_device *netdev, u32 defer) { + unsigned int count =3D max(netdev->num_rx_queues, + netdev->num_tx_queues); struct napi_struct *napi; + int i; =20 WRITE_ONCE(netdev->napi_defer_hard_irqs, defer); list_for_each_entry(napi, &netdev->napi_list, dev_list) napi_set_defer_hard_irqs(napi, defer); + + for (i =3D 0; i < count; i++) + netdev->napi_config[i].defer_hard_irqs =3D defer; } =20 /** @@ -206,11 +212,17 @@ static inline void napi_set_gro_flush_timeout(struct = napi_struct *n, static inline void netdev_set_gro_flush_timeout(struct net_device *netdev, unsigned long timeout) { + unsigned int count =3D max(netdev->num_rx_queues, + netdev->num_tx_queues); struct napi_struct *napi; + int i; =20 WRITE_ONCE(netdev->gro_flush_timeout, timeout); list_for_each_entry(napi, &netdev->napi_list, dev_list) napi_set_gro_flush_timeout(napi, timeout); + + for (i =3D 0; i < count; i++) + netdev->napi_config[i].gro_flush_timeout =3D timeout; } =20 int rps_cpumask_housekeeping(struct cpumask *mask); --=20 2.25.1