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authorEric Dumazet <dada1@cosmosbay.com>2006-10-18 23:51:57 -0400
committerDavid S. Miller <davem@davemloft.net>2006-10-18 23:51:57 -0400
commit5175c3786c244f8b689854db24c9e79b1c6a084f (patch)
tree459975fe6a7b6dd5294b362397b185959b4ab96d
parent9ce8ade015a3f82dbdf856df7a685878dd1cc0e1 (diff)
[NET]: reduce per cpu ram used for loopback stats
We dont need a full struct net_device_stats (currently 23 long : 184 bytes on x86_64) per possible CPU, but only two counters : bytes and packets We save few CPU cycles too in loopback_xmit() not updating 4 fields, but 2. Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--drivers/net/loopback.c35
1 files changed, 19 insertions, 16 deletions
diff --git a/drivers/net/loopback.c b/drivers/net/loopback.c
index 4178b4b1d2df..93fbea1c9271 100644
--- a/drivers/net/loopback.c
+++ b/drivers/net/loopback.c
@@ -58,7 +58,11 @@
58#include <linux/tcp.h> 58#include <linux/tcp.h>
59#include <linux/percpu.h> 59#include <linux/percpu.h>
60 60
61static DEFINE_PER_CPU(struct net_device_stats, loopback_stats); 61struct pcpu_lstats {
62 unsigned long packets;
63 unsigned long bytes;
64};
65static DEFINE_PER_CPU(struct pcpu_lstats, pcpu_lstats);
62 66
63#define LOOPBACK_OVERHEAD (128 + MAX_HEADER + 16 + 16) 67#define LOOPBACK_OVERHEAD (128 + MAX_HEADER + 16 + 16)
64 68
@@ -128,7 +132,7 @@ static void emulate_large_send_offload(struct sk_buff *skb)
128 */ 132 */
129static int loopback_xmit(struct sk_buff *skb, struct net_device *dev) 133static int loopback_xmit(struct sk_buff *skb, struct net_device *dev)
130{ 134{
131 struct net_device_stats *lb_stats; 135 struct pcpu_lstats *lb_stats;
132 136
133 skb_orphan(skb); 137 skb_orphan(skb);
134 138
@@ -149,11 +153,9 @@ static int loopback_xmit(struct sk_buff *skb, struct net_device *dev)
149#endif 153#endif
150 dev->last_rx = jiffies; 154 dev->last_rx = jiffies;
151 155
152 lb_stats = &per_cpu(loopback_stats, get_cpu()); 156 lb_stats = &per_cpu(pcpu_lstats, get_cpu());
153 lb_stats->rx_bytes += skb->len; 157 lb_stats->bytes += skb->len;
154 lb_stats->tx_bytes = lb_stats->rx_bytes; 158 lb_stats->packets++;
155 lb_stats->rx_packets++;
156 lb_stats->tx_packets = lb_stats->rx_packets;
157 put_cpu(); 159 put_cpu();
158 160
159 netif_rx(skb); 161 netif_rx(skb);
@@ -166,20 +168,21 @@ static struct net_device_stats loopback_stats;
166static struct net_device_stats *get_stats(struct net_device *dev) 168static struct net_device_stats *get_stats(struct net_device *dev)
167{ 169{
168 struct net_device_stats *stats = &loopback_stats; 170 struct net_device_stats *stats = &loopback_stats;
171 unsigned long bytes = 0;
172 unsigned long packets = 0;
169 int i; 173 int i;
170 174
171 memset(stats, 0, sizeof(struct net_device_stats));
172
173 for_each_possible_cpu(i) { 175 for_each_possible_cpu(i) {
174 struct net_device_stats *lb_stats; 176 const struct pcpu_lstats *lb_stats;
175 177
176 lb_stats = &per_cpu(loopback_stats, i); 178 lb_stats = &per_cpu(pcpu_lstats, i);
177 stats->rx_bytes += lb_stats->rx_bytes; 179 bytes += lb_stats->bytes;
178 stats->tx_bytes += lb_stats->tx_bytes; 180 packets += lb_stats->packets;
179 stats->rx_packets += lb_stats->rx_packets;
180 stats->tx_packets += lb_stats->tx_packets;
181 } 181 }
182 182 stats->rx_packets = packets;
183 stats->tx_packets = packets;
184 stats->rx_bytes = bytes;
185 stats->tx_bytes = bytes;
183 return stats; 186 return stats;
184} 187}
185 188