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Miller" , Paolo Abeni , Jiri Pirko , Sebastian Andrzej Siewior , Lorenzo Bianconi , Breno Leitao , Johannes Berg , Alexander Lobakin , linux-kernel@vger.kernel.org (open list) Subject: [PATCH net-next 1/5] net: napi: Make napi_defer_hard_irqs per-NAPI Date: Thu, 29 Aug 2024 13:11:57 +0000 Message-Id: <20240829131214.169977-2-jdamato@fastly.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20240829131214.169977-1-jdamato@fastly.com> References: <20240829131214.169977-1-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" Allow per-NAPI defer_hard_irqs setting. The existing sysfs parameter is respected; writes to sysfs will write to all NAPI structs for the device and the net_device defer_hard_irq field. Reads from sysfs will read from the net_device field. sysfs code was updated to guard against what appears to be a potential overflow as the field is an int, but the value passed in is an unsigned long. The ability to set defer_hard_irqs on specific NAPI instances will be added in a later commit, via netdev-genl. Signed-off-by: Joe Damato Reviewed-by: Martin Karsten Tested-by: Martin Karsten --- include/linux/netdevice.h | 23 +++++++++++++++++++++++ net/core/dev.c | 29 ++++++++++++++++++++++++++--- net/core/net-sysfs.c | 5 ++++- 3 files changed, 53 insertions(+), 4 deletions(-) diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index fce70990b209..7d53380da4c0 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -371,6 +371,7 @@ struct napi_struct { struct list_head rx_list; /* Pending GRO_NORMAL skbs */ int rx_count; /* length of rx_list */ unsigned int napi_id; + int defer_hard_irqs; struct hrtimer timer; struct task_struct *thread; /* control-path-only fields follow */ @@ -534,6 +535,28 @@ static inline void napi_schedule_irqoff(struct napi_st= ruct *n) __napi_schedule_irqoff(n); } =20 +/** + * napi_get_defer_hard_irqs - get the NAPI's defer_hard_irqs + * @n: napi struct to get the defer_hard_irqs field from + * + * Returns the per-NAPI value of the defar_hard_irqs field. + */ +int napi_get_defer_hard_irqs(const struct napi_struct *n); + +/** + * napi_set_defer_hard_irqs - set the defer_hard_irqs for a napi + * @n: napi_struct to set the defer_hard_irqs field + * @defer: the value the field should be set to + */ +void napi_set_defer_hard_irqs(struct napi_struct *n, int defer); + +/** + * netdev_set_defer_hard_irqs - set defer_hard_irqs for all NAPIs of a net= dev + * @netdev: the net_device for which all NAPIs will have their defer_hard_= irqs set + * @defer: the defer_hard_irqs value to set + */ +void netdev_set_defer_hard_irqs(struct net_device *netdev, int defer); + /** * napi_complete_done - NAPI processing complete * @n: NAPI context diff --git a/net/core/dev.c b/net/core/dev.c index 63987b8b7c85..f7baff0da057 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -6212,6 +6212,28 @@ void __napi_schedule_irqoff(struct napi_struct *n) } EXPORT_SYMBOL(__napi_schedule_irqoff); =20 +int napi_get_defer_hard_irqs(const struct napi_struct *n) +{ + return READ_ONCE(n->defer_hard_irqs); +} +EXPORT_SYMBOL_GPL(napi_get_defer_hard_irqs); + +void napi_set_defer_hard_irqs(struct napi_struct *n, int defer) +{ + WRITE_ONCE(n->defer_hard_irqs, defer); +} +EXPORT_SYMBOL_GPL(napi_set_defer_hard_irqs); + +void netdev_set_defer_hard_irqs(struct net_device *netdev, int defer) +{ + struct napi_struct *napi; + + 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); +} +EXPORT_SYMBOL_GPL(netdev_set_defer_hard_irqs); + bool napi_complete_done(struct napi_struct *n, int work_done) { unsigned long flags, val, new, timeout =3D 0; @@ -6230,7 +6252,7 @@ bool napi_complete_done(struct napi_struct *n, int wo= rk_done) if (work_done) { if (n->gro_bitmask) timeout =3D READ_ONCE(n->dev->gro_flush_timeout); - n->defer_hard_irqs_count =3D READ_ONCE(n->dev->napi_defer_hard_irqs); + n->defer_hard_irqs_count =3D napi_get_defer_hard_irqs(n); } if (n->defer_hard_irqs_count > 0) { n->defer_hard_irqs_count--; @@ -6368,7 +6390,7 @@ static void busy_poll_stop(struct napi_struct *napi, = void *have_poll_lock, bpf_net_ctx =3D bpf_net_ctx_set(&__bpf_net_ctx); =20 if (flags & NAPI_F_PREFER_BUSY_POLL) { - napi->defer_hard_irqs_count =3D READ_ONCE(napi->dev->napi_defer_hard_irq= s); + napi->defer_hard_irqs_count =3D napi_get_defer_hard_irqs(napi); timeout =3D READ_ONCE(napi->dev->gro_flush_timeout); if (napi->defer_hard_irqs_count && timeout) { hrtimer_start(&napi->timer, ns_to_ktime(timeout), HRTIMER_MODE_REL_PINN= ED); @@ -6650,6 +6672,7 @@ 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)); init_gro_hash(napi); napi->skb =3D NULL; INIT_LIST_HEAD(&napi->rx_list); @@ -11032,7 +11055,7 @@ void netdev_sw_irq_coalesce_default_on(struct net_d= evice *dev) =20 if (!IS_ENABLED(CONFIG_PREEMPT_RT)) { dev->gro_flush_timeout =3D 20000; - dev->napi_defer_hard_irqs =3D 1; + netdev_set_defer_hard_irqs(dev, 1); } } EXPORT_SYMBOL_GPL(netdev_sw_irq_coalesce_default_on); diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c index 0e2084ce7b75..8272f0144d81 100644 --- a/net/core/net-sysfs.c +++ b/net/core/net-sysfs.c @@ -425,7 +425,10 @@ NETDEVICE_SHOW_RW(gro_flush_timeout, fmt_ulong); =20 static int change_napi_defer_hard_irqs(struct net_device *dev, unsigned lo= ng val) { - WRITE_ONCE(dev->napi_defer_hard_irqs, val); + if (val > S32_MAX) + return -EINVAL; + + netdev_set_defer_hard_irqs(dev, (int)val); return 0; } =20 --=20 2.25.1