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64b0dc517e
Rename LL_SO to BUSY_POLL_SO
Rename sysctl_net_ll_{read,poll} to sysctl_busy_{read,poll}
Fix up users of these variables.
Fix documentation for sysctl.
a patch for the socket.7 man page will follow separately,
because of limitations of my mail setup.
Signed-off-by: Eliezer Tamir <eliezer.tamir@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
186 lines
4.4 KiB
C
186 lines
4.4 KiB
C
/*
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* net busy poll support
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* Copyright(c) 2013 Intel Corporation.
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms and conditions of the GNU General Public License,
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* version 2, as published by the Free Software Foundation.
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*
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* This program is distributed in the hope it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* more details.
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*
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* You should have received a copy of the GNU General Public License along with
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* this program; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Author: Eliezer Tamir
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*
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* Contact Information:
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* e1000-devel Mailing List <e1000-devel@lists.sourceforge.net>
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*/
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#ifndef _LINUX_NET_BUSY_POLL_H
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#define _LINUX_NET_BUSY_POLL_H
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#include <linux/netdevice.h>
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#include <net/ip.h>
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#ifdef CONFIG_NET_LL_RX_POLL
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struct napi_struct;
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extern unsigned int sysctl_net_busy_read __read_mostly;
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extern unsigned int sysctl_net_busy_poll __read_mostly;
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/* return values from ndo_ll_poll */
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#define LL_FLUSH_FAILED -1
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#define LL_FLUSH_BUSY -2
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static inline bool net_busy_loop_on(void)
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{
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return sysctl_net_busy_poll;
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}
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/* a wrapper to make debug_smp_processor_id() happy
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* we can use sched_clock() because we don't care much about precision
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* we only care that the average is bounded
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*/
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#ifdef CONFIG_DEBUG_PREEMPT
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static inline u64 busy_loop_us_clock(void)
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{
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u64 rc;
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preempt_disable_notrace();
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rc = sched_clock();
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preempt_enable_no_resched_notrace();
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return rc >> 10;
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}
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#else /* CONFIG_DEBUG_PREEMPT */
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static inline u64 busy_loop_us_clock(void)
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{
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return sched_clock() >> 10;
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}
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#endif /* CONFIG_DEBUG_PREEMPT */
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static inline unsigned long sk_busy_loop_end_time(struct sock *sk)
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{
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return busy_loop_us_clock() + ACCESS_ONCE(sk->sk_ll_usec);
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}
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/* in poll/select we use the global sysctl_net_ll_poll value */
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static inline unsigned long busy_loop_end_time(void)
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{
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return busy_loop_us_clock() + ACCESS_ONCE(sysctl_net_busy_poll);
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}
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static inline bool sk_can_busy_loop(struct sock *sk)
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{
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return sk->sk_ll_usec && sk->sk_napi_id &&
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!need_resched() && !signal_pending(current);
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}
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static inline bool busy_loop_timeout(unsigned long end_time)
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{
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unsigned long now = busy_loop_us_clock();
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return time_after(now, end_time);
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}
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/* when used in sock_poll() nonblock is known at compile time to be true
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* so the loop and end_time will be optimized out
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*/
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static inline bool sk_busy_loop(struct sock *sk, int nonblock)
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{
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unsigned long end_time = !nonblock ? sk_busy_loop_end_time(sk) : 0;
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const struct net_device_ops *ops;
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struct napi_struct *napi;
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int rc = false;
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/*
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* rcu read lock for napi hash
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* bh so we don't race with net_rx_action
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*/
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rcu_read_lock_bh();
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napi = napi_by_id(sk->sk_napi_id);
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if (!napi)
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goto out;
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ops = napi->dev->netdev_ops;
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if (!ops->ndo_busy_poll)
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goto out;
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do {
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rc = ops->ndo_busy_poll(napi);
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if (rc == LL_FLUSH_FAILED)
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break; /* permanent failure */
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if (rc > 0)
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/* local bh are disabled so it is ok to use _BH */
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NET_ADD_STATS_BH(sock_net(sk),
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LINUX_MIB_LOWLATENCYRXPACKETS, rc);
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} while (!nonblock && skb_queue_empty(&sk->sk_receive_queue) &&
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!need_resched() && !busy_loop_timeout(end_time));
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rc = !skb_queue_empty(&sk->sk_receive_queue);
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out:
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rcu_read_unlock_bh();
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return rc;
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}
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/* used in the NIC receive handler to mark the skb */
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static inline void skb_mark_napi_id(struct sk_buff *skb,
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struct napi_struct *napi)
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{
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skb->napi_id = napi->napi_id;
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}
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/* used in the protocol hanlder to propagate the napi_id to the socket */
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static inline void sk_mark_napi_id(struct sock *sk, struct sk_buff *skb)
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{
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sk->sk_napi_id = skb->napi_id;
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}
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#else /* CONFIG_NET_LL_RX_POLL */
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static inline unsigned long net_busy_loop_on(void)
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{
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return 0;
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}
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static inline unsigned long busy_loop_end_time(void)
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{
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return 0;
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}
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static inline bool sk_can_busy_loop(struct sock *sk)
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{
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return false;
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}
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static inline bool sk_busy_poll(struct sock *sk, int nonblock)
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{
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return false;
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}
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static inline void skb_mark_napi_id(struct sk_buff *skb,
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struct napi_struct *napi)
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{
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}
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static inline void sk_mark_napi_id(struct sock *sk, struct sk_buff *skb)
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{
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}
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static inline bool busy_loop_timeout(unsigned long end_time)
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{
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return true;
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}
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#endif /* CONFIG_NET_LL_RX_POLL */
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#endif /* _LINUX_NET_BUSY_POLL_H */
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