diff options
| author |   Tom Herbert <therbert@google.com> | 2010-05-20 18:37:59 +0000 |
|---|---|---|
| committer |   David S. Miller <davem@davemloft.net> | 2010-05-21 00:38:33 -0700 |
| commit | 76cc8b13a6e41b537fd262b600da1571314add62 (patch) | |
| tree | a8a25a4f23be5c0eeed77dd9fcb30dc9b315e519 /net/core/dev.c | |
| parent | can: SJA1000 add missing spin_lock_init() (diff) | |
| download | linux-dev-76cc8b13a6e41b537fd262b600da1571314add62.tar.xz linux-dev-76cc8b13a6e41b537fd262b600da1571314add62.zip | |
net: fix problem in dequeuing from input_pkt_queue
Fix some issues introduced in batch skb dequeuing for input_pkt_queue.
The primary issue it that the queue head must be incremented only
after a packet has been processed, that is only after
__netif_receive_skb has been called. This is needed for the mechanism
to prevent OOO packet in RFS. Also when flushing the input_pkt_queue
and process_queue, the process queue should be done first to prevent
OOO packets.
Because the input_pkt_queue has been effectively split into two queues,
the calculation of the tail ptr is no longer correct. The correct value
would be head+input_pkt_queue->len+process_queue->len. To avoid
this calculation we added an explict input_queue_tail in softnet_data.
The tail value is simply incremented when queuing to input_pkt_queue.
Signed-off-by: Tom Herbert <therbert@google.com>
Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/core/dev.c')
| -rw-r--r-- | net/core/dev.c | 28 |
1 files changed, 15 insertions, 13 deletions
diff --git a/net/core/dev.c b/net/core/dev.c index 6c820650b80f..0aab66d68b19 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -2426,10 +2426,7 @@ static int enqueue_to_backlog(struct sk_buff *skb, int cpu, if (skb_queue_len(&sd->input_pkt_queue)) { enqueue: __skb_queue_tail(&sd->input_pkt_queue, skb); -#ifdef CONFIG_RPS - *qtail = sd->input_queue_head + - skb_queue_len(&sd->input_pkt_queue); -#endif + input_queue_tail_incr_save(sd, qtail); rps_unlock(sd); local_irq_restore(flags); return NET_RX_SUCCESS; @@ -2964,7 +2961,7 @@ static void flush_backlog(void *arg) if (skb->dev == dev) { __skb_unlink(skb, &sd->input_pkt_queue); kfree_skb(skb); - input_queue_head_add(sd, 1); + input_queue_head_incr(sd); } } rps_unlock(sd); @@ -2973,6 +2970,7 @@ static void flush_backlog(void *arg) if (skb->dev == dev) { __skb_unlink(skb, &sd->process_queue); kfree_skb(skb); + input_queue_head_incr(sd); } } } @@ -3328,18 +3326,20 @@ static int process_backlog(struct napi_struct *napi, int quota) while ((skb = __skb_dequeue(&sd->process_queue))) { local_irq_enable(); __netif_receive_skb(skb); - if (++work >= quota) - return work; local_irq_disable(); + input_queue_head_incr(sd); + if (++work >= quota) { + local_irq_enable(); + return work; + } } rps_lock(sd); qlen = skb_queue_len(&sd->input_pkt_queue); - if (qlen) { - input_queue_head_add(sd, qlen); + if (qlen) skb_queue_splice_tail_init(&sd->input_pkt_queue, &sd->process_queue); - } + if (qlen < quota - work) { /* * Inline a custom version of __napi_complete(). @@ -5679,12 +5679,14 @@ static int dev_cpu_callback(struct notifier_block *nfb, local_irq_enable(); /* Process offline CPU's input_pkt_queue */ - while ((skb = __skb_dequeue(&oldsd->input_pkt_queue))) { + while ((skb = __skb_dequeue(&oldsd->process_queue))) { netif_rx(skb); - input_queue_head_add(oldsd, 1); + input_queue_head_incr(oldsd); } - while ((skb = __skb_dequeue(&oldsd->process_queue))) + while ((skb = __skb_dequeue(&oldsd->input_pkt_queue))) { netif_rx(skb); + input_queue_head_incr(oldsd); + } return NOTIFY_OK; } |