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udp: use atomic_inc_not_zero_hint

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UDP sockets refcount is usually 2, unless an incoming frame is going to
be queued in receive or backlog queue.

Using atomic_inc_not_zero_hint() permits to reduce latency, because
processor issues less memory transactions.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet
2010-11-15 19:58:26 +00:00
committed by David S. Miller
parent 213b15ca81
commit c31504dc0d
3 changed files with 5 additions and 5 deletions
Download Patch File Download Diff File Expand all files Collapse all files

2
include/net/sock.h
View File

@@ -57,7 +57,7 @@
#include <linux/rculist_nulls.h> #include <linux/rculist_nulls.h>
#include <linux/poll.h> #include <linux/poll.h>
#include <asm/atomic.h> #include <linux/atomic.h>
#include <net/dst.h> #include <net/dst.h>
#include <net/checksum.h> #include <net/checksum.h>

4
net/ipv4/udp.c
View File

@@ -430,7 +430,7 @@ begin:
if (result) { if (result) {
exact_match: exact_match:
if (unlikely(!atomic_inc_not_zero(&result->sk_refcnt))) if (unlikely(!atomic_inc_not_zero_hint(&result->sk_refcnt, 2)))
result = NULL; result = NULL;
else if (unlikely(compute_score2(result, net, saddr, sport, else if (unlikely(compute_score2(result, net, saddr, sport,
daddr, hnum, dif) < badness)) { daddr, hnum, dif) < badness)) {
@@ -500,7 +500,7 @@ begin:
goto begin; goto begin;
if (result) { if (result) {
if (unlikely(!atomic_inc_not_zero(&result->sk_refcnt))) if (unlikely(!atomic_inc_not_zero_hint(&result->sk_refcnt, 2)))
result = NULL; result = NULL;
else if (unlikely(compute_score(result, net, saddr, hnum, sport, else if (unlikely(compute_score(result, net, saddr, hnum, sport,
daddr, dport, dif) < badness)) { daddr, dport, dif) < badness)) {

4
net/ipv6/udp.c
View File

@@ -227,7 +227,7 @@ begin:
if (result) { if (result) {
exact_match: exact_match:
if (unlikely(!atomic_inc_not_zero(&result->sk_refcnt))) if (unlikely(!atomic_inc_not_zero_hint(&result->sk_refcnt, 2)))
result = NULL; result = NULL;
else if (unlikely(compute_score2(result, net, saddr, sport, else if (unlikely(compute_score2(result, net, saddr, sport,
daddr, hnum, dif) < badness)) { daddr, hnum, dif) < badness)) {
@@ -294,7 +294,7 @@ begin:
goto begin; goto begin;
if (result) { if (result) {
if (unlikely(!atomic_inc_not_zero(&result->sk_refcnt))) if (unlikely(!atomic_inc_not_zero_hint(&result->sk_refcnt, 2)))
result = NULL; result = NULL;
else if (unlikely(compute_score(result, net, hnum, saddr, sport, else if (unlikely(compute_score(result, net, hnum, saddr, sport,
daddr, dport, dif) < badness)) { daddr, dport, dif) < badness)) {