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37056719bb
This patch flips the logic we were using to determine if the busy polling has timed out. The main motivation for this is that we will need to support two different possible timeout values in the future and by recording the start time rather than when we would want to end we can focus on making the end_time specific to the task be it epoll or socket based polling. Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
142 lines
3.5 KiB
C
142 lines
3.5 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 <linux/sched/clock.h>
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#include <linux/sched/signal.h>
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#include <net/ip.h>
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#ifdef CONFIG_NET_RX_BUSY_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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/* 0 - Reserved to indicate value not set
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* 1..NR_CPUS - Reserved for sender_cpu
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* NR_CPUS+1..~0 - Region available for NAPI IDs
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*/
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#define MIN_NAPI_ID ((unsigned int)(NR_CPUS + 1))
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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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static inline bool sk_can_busy_loop(const struct sock *sk)
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{
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return sk->sk_ll_usec && !signal_pending(current);
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}
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void sk_busy_loop(struct sock *sk, int nonblock);
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#else /* CONFIG_NET_RX_BUSY_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 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 void sk_busy_loop(struct sock *sk, int nonblock)
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{
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}
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#endif /* CONFIG_NET_RX_BUSY_POLL */
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static inline unsigned long busy_loop_current_time(void)
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{
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#ifdef CONFIG_NET_RX_BUSY_POLL
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return (unsigned long)(local_clock() >> 10);
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#else
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return 0;
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#endif
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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 bool busy_loop_timeout(unsigned long start_time)
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{
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#ifdef CONFIG_NET_RX_BUSY_POLL
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unsigned long bp_usec = READ_ONCE(sysctl_net_busy_poll);
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if (bp_usec) {
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unsigned long end_time = start_time + bp_usec;
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unsigned long now = busy_loop_current_time();
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return time_after(now, end_time);
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}
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#endif
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return true;
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}
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static inline bool sk_busy_loop_timeout(struct sock *sk,
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unsigned long start_time)
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{
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#ifdef CONFIG_NET_RX_BUSY_POLL
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unsigned long bp_usec = READ_ONCE(sk->sk_ll_usec);
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if (bp_usec) {
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unsigned long end_time = start_time + bp_usec;
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unsigned long now = busy_loop_current_time();
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return time_after(now, end_time);
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}
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#endif
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return true;
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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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#ifdef CONFIG_NET_RX_BUSY_POLL
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skb->napi_id = napi->napi_id;
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#endif
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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, const struct sk_buff *skb)
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{
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#ifdef CONFIG_NET_RX_BUSY_POLL
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sk->sk_napi_id = skb->napi_id;
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#endif
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}
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/* variant used for unconnected sockets */
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static inline void sk_mark_napi_id_once(struct sock *sk,
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const struct sk_buff *skb)
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{
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#ifdef CONFIG_NET_RX_BUSY_POLL
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if (!sk->sk_napi_id)
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sk->sk_napi_id = skb->napi_id;
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#endif
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}
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#endif /* _LINUX_NET_BUSY_POLL_H */
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