mirror of
https://github.com/torvalds/linux.git
synced 2024-11-22 12:11:40 +00:00
b4e8ae5c8c
This adds the napi_busy_loop_rcu() function. This function assumes that the calling function is already holding the rcu read lock and napi_busy_loop() does not need to take the rcu read lock. Add a NAPI_F_NO_SCHED flag, which tells __napi_busy_loop() to abort if we need to reschedule rather than drop the RCU read lock and reschedule. Signed-off-by: Stefan Roesch <shr@devkernel.io> Link: https://lore.kernel.org/r/20230608163839.2891748-3-shr@devkernel.io Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
183 lines
4.4 KiB
C
183 lines
4.4 KiB
C
/* SPDX-License-Identifier: GPL-2.0-only */
|
|
/*
|
|
* net busy poll support
|
|
* Copyright(c) 2013 Intel Corporation.
|
|
*
|
|
* Author: Eliezer Tamir
|
|
*
|
|
* Contact Information:
|
|
* e1000-devel Mailing List <e1000-devel@lists.sourceforge.net>
|
|
*/
|
|
|
|
#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))
|
|
|
|
#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);
|
|
|
|
#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)(local_clock() >> 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,
|
|
unsigned long start_time)
|
|
{
|
|
#ifdef CONFIG_NET_RX_BUSY_POLL
|
|
unsigned long bp_usec = READ_ONCE(sk->sk_ll_usec);
|
|
|
|
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 void sk_busy_loop(struct sock *sk, int nonblock)
|
|
{
|
|
#ifdef CONFIG_NET_RX_BUSY_POLL
|
|
unsigned int napi_id = READ_ONCE(sk->sk_napi_id);
|
|
|
|
if (napi_id >= MIN_NAPI_ID)
|
|
napi_busy_loop(napi_id, nonblock ? NULL : sk_busy_loop_end, sk,
|
|
READ_ONCE(sk->sk_prefer_busy_poll),
|
|
READ_ONCE(sk->sk_busy_poll_budget) ?: BUSY_POLL_BUDGET);
|
|
#endif
|
|
}
|
|
|
|
/* used in the NIC receive handler to mark the skb */
|
|
static inline void skb_mark_napi_id(struct sk_buff *skb,
|
|
struct napi_struct *napi)
|
|
{
|
|
#ifdef CONFIG_NET_RX_BUSY_POLL
|
|
/* If the skb was already marked with a valid NAPI ID, avoid overwriting
|
|
* it.
|
|
*/
|
|
if (skb->napi_id < MIN_NAPI_ID)
|
|
skb->napi_id = napi->napi_id;
|
|
#endif
|
|
}
|
|
|
|
/* used in the protocol hanlder to propagate the napi_id to the socket */
|
|
static inline void sk_mark_napi_id(struct sock *sk, const struct sk_buff *skb)
|
|
{
|
|
#ifdef CONFIG_NET_RX_BUSY_POLL
|
|
if (unlikely(READ_ONCE(sk->sk_napi_id) != skb->napi_id))
|
|
WRITE_ONCE(sk->sk_napi_id, skb->napi_id);
|
|
#endif
|
|
sk_rx_queue_update(sk, skb);
|
|
}
|
|
|
|
/* Variant of sk_mark_napi_id() for passive flow setup,
|
|
* as sk->sk_napi_id and sk->sk_rx_queue_mapping content
|
|
* needs to be set.
|
|
*/
|
|
static inline void sk_mark_napi_id_set(struct sock *sk,
|
|
const struct sk_buff *skb)
|
|
{
|
|
#ifdef CONFIG_NET_RX_BUSY_POLL
|
|
WRITE_ONCE(sk->sk_napi_id, skb->napi_id);
|
|
#endif
|
|
sk_rx_queue_set(sk, skb);
|
|
}
|
|
|
|
static inline void __sk_mark_napi_id_once(struct sock *sk, unsigned int napi_id)
|
|
{
|
|
#ifdef CONFIG_NET_RX_BUSY_POLL
|
|
if (!READ_ONCE(sk->sk_napi_id))
|
|
WRITE_ONCE(sk->sk_napi_id, napi_id);
|
|
#endif
|
|
}
|
|
|
|
/* variant used for unconnected sockets */
|
|
static inline void sk_mark_napi_id_once(struct sock *sk,
|
|
const struct sk_buff *skb)
|
|
{
|
|
#ifdef CONFIG_NET_RX_BUSY_POLL
|
|
__sk_mark_napi_id_once(sk, skb->napi_id);
|
|
#endif
|
|
}
|
|
|
|
static inline void sk_mark_napi_id_once_xdp(struct sock *sk,
|
|
const struct xdp_buff *xdp)
|
|
{
|
|
#ifdef CONFIG_NET_RX_BUSY_POLL
|
|
__sk_mark_napi_id_once(sk, xdp->rxq->napi_id);
|
|
#endif
|
|
}
|
|
|
|
#endif /* _LINUX_NET_BUSY_POLL_H */
|