include/net/busy_poll.h

Source file repositories/reference/linux-study-clean/include/net/busy_poll.h

File Facts

System
Linux kernel
Corpus path
include/net/busy_poll.h
Extension
.h
Size
4685 bytes
Lines
189
Domain
Networking Core
Bucket
Sockets, Protocols, Packet Path, And Network Policy
Inferred role
Networking Core: implementation source
Status
source implementation candidate

Why This File Exists

Networking stack implementation surface: socket APIs, protocol dispatch, packet flow, routing, filtering, and network namespaces.

Dependency Surface

Detected Declarations

Annotated Snippet

#ifndef _LINUX_NET_BUSY_POLL_H
#define _LINUX_NET_BUSY_POLL_H

#include <linux/netdevice.h>
#include <linux/sched/clock.h>
#include <linux/sched/signal.h>
#include <net/ip.h>
#include <net/xdp.h>

/*		0 - Reserved to indicate value not set
 *     1..NR_CPUS - Reserved for sender_cpu
 *  NR_CPUS+1..~0 - Region available for NAPI IDs
 */
#define MIN_NAPI_ID ((unsigned int)(NR_CPUS + 1))

static inline bool napi_id_valid(unsigned int napi_id)
{
	return napi_id >= MIN_NAPI_ID;
}

#define BUSY_POLL_BUDGET 8

#ifdef CONFIG_NET_RX_BUSY_POLL

struct napi_struct;
extern unsigned int sysctl_net_busy_read __read_mostly;
extern unsigned int sysctl_net_busy_poll __read_mostly;

static inline bool net_busy_loop_on(void)
{
	return READ_ONCE(sysctl_net_busy_poll);
}

static inline bool sk_can_busy_loop(const struct sock *sk)
{
	return READ_ONCE(sk->sk_ll_usec) && !signal_pending(current);
}

bool sk_busy_loop_end(void *p, unsigned long start_time);

void napi_busy_loop(unsigned int napi_id,
		    bool (*loop_end)(void *, unsigned long),
		    void *loop_end_arg, bool prefer_busy_poll, u16 budget);

void napi_busy_loop_rcu(unsigned int napi_id,
			bool (*loop_end)(void *, unsigned long),
			void *loop_end_arg, bool prefer_busy_poll, u16 budget);

void napi_suspend_irqs(unsigned int napi_id);
void napi_resume_irqs(unsigned int napi_id);

#else /* CONFIG_NET_RX_BUSY_POLL */
static inline unsigned long net_busy_loop_on(void)
{
	return 0;
}

static inline bool sk_can_busy_loop(struct sock *sk)
{
	return false;
}

#endif /* CONFIG_NET_RX_BUSY_POLL */

static inline unsigned long busy_loop_current_time(void)
{
#ifdef CONFIG_NET_RX_BUSY_POLL
	return (unsigned long)(ktime_get_ns() >> 10);
#else
	return 0;
#endif
}

/* in poll/select we use the global sysctl_net_ll_poll value */
static inline bool busy_loop_timeout(unsigned long start_time)
{
#ifdef CONFIG_NET_RX_BUSY_POLL
	unsigned long bp_usec = READ_ONCE(sysctl_net_busy_poll);

	if (bp_usec) {
		unsigned long end_time = start_time + bp_usec;
		unsigned long now = busy_loop_current_time();

		return time_after(now, end_time);
	}
#endif
	return true;
}

static inline bool sk_busy_loop_timeout(struct sock *sk,

Annotation

Implementation Notes