[PATCH 3/3] netpoll: use skb_buff_head for skb cache

[Stephen Hemminger]

The private skb cache should be managed with normal skb_buff_head rather
than a DIY queue. If pool is exhausted, don't print anything that just
makes the problem worse. After a number of attempts, punt and drop
the message (callers handle it already).

Signed-off-by: Stephen Hemminger <[EMAIL PROTECTED]>

---
 net/core/netpoll.c |   55 +++++++++++++++++++++--------------------------------
 1 file changed, 22 insertions(+), 33 deletions(-)

--- linux-2.6.orig/net/core/netpoll.c   2006-10-19 09:49:03.000000000 -0700
+++ linux-2.6/net/core/netpoll.c        2006-10-19 10:06:39.000000000 -0700
@@ -36,9 +36,7 @@
 #define MAX_QUEUE_DEPTH (MAX_SKBS / 2)
 #define MAX_RETRIES 20000
 
-static DEFINE_SPINLOCK(skb_list_lock);
-static int nr_skbs;
-static struct sk_buff *skbs;
+static struct sk_buff_head skb_list;
 
 static atomic_t trapped;
 
@@ -51,6 +49,7 @@
 
 static void zap_completion_queue(void);
 static void arp_reply(struct sk_buff *skb);
+static void refill_skbs(void);
 
 static void netpoll_run(unsigned long arg)
 {
@@ -79,6 +78,7 @@
                        break;
                }
        }
+       refill_skbs();
 }
 
 static int checksum_udp(struct sk_buff *skb, struct udphdr *uh,
@@ -169,19 +169,14 @@
 static void refill_skbs(void)
 {
        struct sk_buff *skb;
-       unsigned long flags;
 
-       spin_lock_irqsave(&skb_list_lock, flags);
-       while (nr_skbs < MAX_SKBS) {
+       while (skb_queue_len(&skb_list) < MAX_SKBS) {
                skb = alloc_skb(MAX_SKB_SIZE, GFP_ATOMIC);
                if (!skb)
                        break;
 
-               skb->next = skbs;
-               skbs = skb;
-               nr_skbs++;
+               skb_queue_tail(&skb_list, skb);
        }
-       spin_unlock_irqrestore(&skb_list_lock, flags);
 }
 
 static void zap_completion_queue(void)
@@ -210,37 +205,24 @@
        put_cpu_var(softnet_data);
 }
 
-static struct sk_buff * find_skb(struct netpoll *np, int len, int reserve)
+static struct sk_buff *find_skb(struct netpoll *np, int len, int reserve)
 {
-       int once = 1, count = 0;
-       unsigned long flags;
-       struct sk_buff *skb = NULL;
+       struct sk_buff *skb;
+       int tries = 0;
 
        zap_completion_queue();
-repeat:
-       if (nr_skbs < MAX_SKBS)
-               refill_skbs();
 
+repeat:
        skb = alloc_skb(len, GFP_ATOMIC);
-
-       if (!skb) {
-               spin_lock_irqsave(&skb_list_lock, flags);
-               skb = skbs;
-               if (skb) {
-                       skbs = skb->next;
-                       skb->next = NULL;
-                       nr_skbs--;
-               }
-               spin_unlock_irqrestore(&skb_list_lock, flags);
-       }
+       if (!skb)
+               skb = skb_dequeue(&skb_list);
 
        if(!skb) {
-               count++;
-               if (once && (count == 1000000)) {
-                       printk("out of netpoll skbs!\n");
-                       once = 0;
-               }
+               if (++tries > MAX_RETRIES)
+                       return NULL;
+
                netpoll_poll(np);
+               tasklet_schedule(&np->dev->npinfo->tx_task);
                goto repeat;
        }
 
@@ -589,6 +571,13 @@
        return -1;
 }
 
+static __init int netpoll_init(void)
+{
+       skb_queue_head_init(&skb_list);
+       return 0;
+}
+core_initcall(netpoll_init);
+
 int netpoll_setup(struct netpoll *np)
 {
        struct net_device *ndev = NULL;

--

-
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to [EMAIL PROTECTED]
More majordomo info at  http://vger.kernel.org/majordomo-info.html