Commit f15e3b3d authored by Joe Damato's avatar Joe Damato Committed by Jakub Kicinski
Browse files

net: napi: Make napi_defer_hard_irqs per-NAPI 



Add defer_hard_irqs to napi_struct in preparation for per-NAPI
settings.

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 show the net_device field.

The ability to set defer_hard_irqs on specific NAPI instances will be
added in a later commit, via netdev-genl.

Signed-off-by: default avatarJoe Damato <jdamato@fastly.com>
Reviewed-by: default avatarEric Dumazet <edumazet@google.com>
Reviewed-by: default avatarJakub Kicinski <kuba@kernel.org>
Link: https://patch.msgid.link/20241011184527.16393-2-jdamato@fastly.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent ff1585e9

Documentation/networking/net_cachelines/net_device.rst

+1 −0
Original line number Diff line number Diff line
@@ -186,4 +186,5 @@ struct dpll_pin* dpll_pin 
struct hlist_head                   page_pools

struct dim_irq_moder*               irq_moder

u64                                 max_pacing_offload_horizon

u32                                 napi_defer_hard_irqs

=================================== =========================== =================== =================== ===================================================================================

include/linux/netdevice.h

+2 −1
Original line number Diff line number Diff line
@@ -373,6 +373,7 @@ struct napi_struct { 
	unsigned int		napi_id;

	struct hrtimer		timer;

	struct task_struct	*thread;

	u32			defer_hard_irqs;

	/* control-path-only fields follow */

	struct list_head	dev_list;

	struct hlist_node	napi_hash_node;
@@ -2085,7 +2086,6 @@ struct net_device { 
	unsigned int		real_num_rx_queues;

	struct netdev_rx_queue	*_rx;

	unsigned long		gro_flush_timeout;

	u32			napi_defer_hard_irqs;

	unsigned int		gro_max_size;

	unsigned int		gro_ipv4_max_size;

	rx_handler_func_t __rcu	*rx_handler;
@@ -2413,6 +2413,7 @@ struct net_device { 
	struct dim_irq_moder	*irq_moder;



	u64			max_pacing_offload_horizon;

	u32			napi_defer_hard_irqs;



	/**

	 * @lock: protects @net_shaper_hierarchy, feel free to use for other

net/core/dev.c

+5 −5
Original line number Diff line number Diff line
@@ -6233,7 +6233,7 @@ bool napi_complete_done(struct napi_struct *n, int work_done) 
	if (work_done) {

		if (n->gro_bitmask)

			timeout = READ_ONCE(n->dev->gro_flush_timeout);

		n->defer_hard_irqs_count = READ_ONCE(n->dev->napi_defer_hard_irqs);

		n->defer_hard_irqs_count = napi_get_defer_hard_irqs(n);

	}

	if (n->defer_hard_irqs_count > 0) {

		n->defer_hard_irqs_count--;
@@ -6371,7 +6371,7 @@ static void busy_poll_stop(struct napi_struct *napi, void *have_poll_lock, 
	bpf_net_ctx = bpf_net_ctx_set(&__bpf_net_ctx);



	if (flags & NAPI_F_PREFER_BUSY_POLL) {

		napi->defer_hard_irqs_count = READ_ONCE(napi->dev->napi_defer_hard_irqs);

		napi->defer_hard_irqs_count = napi_get_defer_hard_irqs(napi);

		timeout = 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_PINNED);
@@ -6653,6 +6653,7 @@ void netif_napi_add_weight(struct net_device *dev, struct napi_struct *napi, 
	INIT_HLIST_NODE(&napi->napi_hash_node);

	hrtimer_init(&napi->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_PINNED);

	napi->timer.function = napi_watchdog;

	napi_set_defer_hard_irqs(napi, READ_ONCE(dev->napi_defer_hard_irqs));

	init_gro_hash(napi);

	napi->skb = NULL;

	INIT_LIST_HEAD(&napi->rx_list);
@@ -11059,7 +11060,7 @@ void netdev_sw_irq_coalesce_default_on(struct net_device *dev) 


	if (!IS_ENABLED(CONFIG_PREEMPT_RT)) {

		dev->gro_flush_timeout = 20000;

		dev->napi_defer_hard_irqs = 1;

		netdev_set_defer_hard_irqs(dev, 1);

	}

}

EXPORT_SYMBOL_GPL(netdev_sw_irq_coalesce_default_on);
@@ -12003,7 +12004,6 @@ static void __init net_dev_struct_check(void) 
	CACHELINE_ASSERT_GROUP_MEMBER(struct net_device, net_device_read_rx, real_num_rx_queues);

	CACHELINE_ASSERT_GROUP_MEMBER(struct net_device, net_device_read_rx, _rx);

	CACHELINE_ASSERT_GROUP_MEMBER(struct net_device, net_device_read_rx, gro_flush_timeout);

	CACHELINE_ASSERT_GROUP_MEMBER(struct net_device, net_device_read_rx, napi_defer_hard_irqs);

	CACHELINE_ASSERT_GROUP_MEMBER(struct net_device, net_device_read_rx, gro_max_size);

	CACHELINE_ASSERT_GROUP_MEMBER(struct net_device, net_device_read_rx, gro_ipv4_max_size);

	CACHELINE_ASSERT_GROUP_MEMBER(struct net_device, net_device_read_rx, rx_handler);
@@ -12015,7 +12015,7 @@ static void __init net_dev_struct_check(void) 
#ifdef CONFIG_NET_XGRESS

	CACHELINE_ASSERT_GROUP_MEMBER(struct net_device, net_device_read_rx, tcx_ingress);

#endif

	CACHELINE_ASSERT_GROUP_SIZE(struct net_device, net_device_read_rx, 104);

	CACHELINE_ASSERT_GROUP_SIZE(struct net_device, net_device_read_rx, 100);

}



/*

net/core/dev.h

+36 −0
Original line number Diff line number Diff line
@@ -148,6 +148,42 @@ static inline void netif_set_gro_ipv4_max_size(struct net_device *dev, 
	WRITE_ONCE(dev->gro_ipv4_max_size, size);

}



/**

 * napi_get_defer_hard_irqs - get the NAPI's defer_hard_irqs

 * @n: napi struct to get the defer_hard_irqs field from

 *

 * Return: the per-NAPI value of the defar_hard_irqs field.

 */

static inline u32 napi_get_defer_hard_irqs(const struct napi_struct *n)

{

	return READ_ONCE(n->defer_hard_irqs);

}



/**

 * 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

 */

static inline void napi_set_defer_hard_irqs(struct napi_struct *n, u32 defer)

{

	WRITE_ONCE(n->defer_hard_irqs, defer);

}



/**

 * netdev_set_defer_hard_irqs - set defer_hard_irqs for all NAPIs of a netdev

 * @netdev: the net_device for which all NAPIs will have defer_hard_irqs set

 * @defer: the defer_hard_irqs value to set

 */

static inline void netdev_set_defer_hard_irqs(struct net_device *netdev,

					      u32 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);

}



int rps_cpumask_housekeeping(struct cpumask *mask);



#if defined(CONFIG_DEBUG_NET) && defined(CONFIG_BPF_SYSCALL)

net/core/net-sysfs.c

+1 −1
Original line number Diff line number Diff line
@@ -429,7 +429,7 @@ static int change_napi_defer_hard_irqs(struct net_device *dev, unsigned long val 
	if (val > S32_MAX)

		return -ERANGE;



	WRITE_ONCE(dev->napi_defer_hard_irqs, val);

	netdev_set_defer_hard_irqs(dev, (u32)val);

	return 0;

}