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Commit a5b50476 authored by Eliezer Tamir's avatar Eliezer Tamir Committed by David S. Miller
Browse files

udp: add low latency socket poll support 



Add upport for busy-polling on UDP sockets.
In __udp[46]_lib_rcv add a call to sk_mark_ll() to copy the napi_id
from the skb into the sk.
This is done at the earliest possible moment, right after we identify
which socket this skb is for.
In __skb_recv_datagram When there is no data and the user
tries to read we busy poll.

Signed-off-by: default avatarAlexander Duyck <alexander.h.duyck@intel.com>
Signed-off-by: default avatarJesse Brandeburg <jesse.brandeburg@intel.com>
Signed-off-by: default avatarEliezer Tamir <eliezer.tamir@linux.intel.com>
Acked-by: default avatarEric Dumazet <edumazet@google.com>
Tested-by: default avatarWillem de Bruijn <willemb@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 06021292

net/core/datagram.c

+4 −0
Original line number Diff line number Diff line
@@ -56,6 +56,7 @@ 
#include <net/sock.h>

#include <net/tcp_states.h>

#include <trace/events/skb.h>

#include <net/ll_poll.h>



/*

 *	Is a socket 'connection oriented' ?
@@ -207,6 +208,9 @@ struct sk_buff *__skb_recv_datagram(struct sock *sk, unsigned int flags, 
		}

		spin_unlock_irqrestore(&queue->lock, cpu_flags);



		if (sk_valid_ll(sk) && sk_poll_ll(sk, flags & MSG_DONTWAIT))

			continue;



		/* User doesn't want to wait */

		error = -EAGAIN;

		if (!timeo)

net/ipv4/udp.c

+5 −1
Original line number Diff line number Diff line
@@ -109,6 +109,7 @@ 
#include <trace/events/udp.h>

#include <linux/static_key.h>

#include <trace/events/skb.h>

#include <net/ll_poll.h>

#include "udp_impl.h"



struct udp_table udp_table __read_mostly;
@@ -1709,7 +1710,10 @@ int __udp4_lib_rcv(struct sk_buff *skb, struct udp_table *udptable, 
	sk = __udp4_lib_lookup_skb(skb, uh->source, uh->dest, udptable);



	if (sk != NULL) {

		int ret = udp_queue_rcv_skb(sk, skb);

		int ret;



		sk_mark_ll(sk, skb);

		ret = udp_queue_rcv_skb(sk, skb);

		sock_put(sk);



		/* a return value > 0 means to resubmit the input, but

net/ipv6/udp.c

+5 −1
Original line number Diff line number Diff line
@@ -46,6 +46,7 @@ 
#include <net/ip6_checksum.h>

#include <net/xfrm.h>

#include <net/inet6_hashtables.h>

#include <net/ll_poll.h>



#include <linux/proc_fs.h>

#include <linux/seq_file.h>
@@ -841,7 +842,10 @@ int __udp6_lib_rcv(struct sk_buff *skb, struct udp_table *udptable, 
	 */

	sk = __udp6_lib_lookup_skb(skb, uh->source, uh->dest, udptable);

	if (sk != NULL) {

		int ret = udpv6_queue_rcv_skb(sk, skb);

		int ret;



		sk_mark_ll(sk, skb);

		ret = udpv6_queue_rcv_skb(sk, skb);

		sock_put(sk);



		/* a return value > 0 means to resubmit the input, but