diff options
author | Changli Gao <xiaosuo@gmail.com> | 2010-04-28 02:07:33 +0400 |
---|---|---|
committer | David S. Miller <davem@davemloft.net> | 2010-04-28 02:11:49 +0400 |
commit | 6e7676c1a76aed6e957611d8d7a9e5592e23aeba (patch) | |
tree | 0cd14260745f755c885466c59182452f637e92e3 /net/core/dev.c | |
parent | c58dc01babfd58ec9e71a6ce080150dc27755d88 (diff) | |
download | linux-6e7676c1a76aed6e957611d8d7a9e5592e23aeba.tar.xz |
net: batch skb dequeueing from softnet input_pkt_queue
batch skb dequeueing from softnet input_pkt_queue to reduce potential lock
contention when RPS is enabled.
Note: in the worst case, the number of packets in a softnet_data may
be double of netdev_max_backlog.
Signed-off-by: Changli Gao <xiaosuo@gmail.com>
Signed-off-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 | 57 |
1 files changed, 39 insertions, 18 deletions
diff --git a/net/core/dev.c b/net/core/dev.c index 3d314919a2cf..100dcbd29739 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -2408,12 +2408,13 @@ static int enqueue_to_backlog(struct sk_buff *skb, int cpu, __get_cpu_var(netdev_rx_stat).total++; rps_lock(sd); - if (sd->input_pkt_queue.qlen <= netdev_max_backlog) { - if (sd->input_pkt_queue.qlen) { + if (skb_queue_len(&sd->input_pkt_queue) <= netdev_max_backlog) { + 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 + sd->input_pkt_queue.qlen; + *qtail = sd->input_queue_head + + skb_queue_len(&sd->input_pkt_queue); #endif rps_unlock(sd); local_irq_restore(flags); @@ -2934,13 +2935,21 @@ static void flush_backlog(void *arg) struct sk_buff *skb, *tmp; rps_lock(sd); - skb_queue_walk_safe(&sd->input_pkt_queue, skb, tmp) + skb_queue_walk_safe(&sd->input_pkt_queue, skb, tmp) { if (skb->dev == dev) { __skb_unlink(skb, &sd->input_pkt_queue); kfree_skb(skb); - input_queue_head_incr(sd); + input_queue_head_add(sd, 1); } + } rps_unlock(sd); + + skb_queue_walk_safe(&sd->process_queue, skb, tmp) { + if (skb->dev == dev) { + __skb_unlink(skb, &sd->process_queue); + kfree_skb(skb); + } + } } static int napi_gro_complete(struct sk_buff *skb) @@ -3286,24 +3295,33 @@ static int process_backlog(struct napi_struct *napi, int quota) } #endif napi->weight = weight_p; - do { + local_irq_disable(); + while (work < quota) { struct sk_buff *skb; + unsigned int qlen; + + while ((skb = __skb_dequeue(&sd->process_queue))) { + local_irq_enable(); + __netif_receive_skb(skb); + if (++work >= quota) + return work; + local_irq_disable(); + } - local_irq_disable(); rps_lock(sd); - skb = __skb_dequeue(&sd->input_pkt_queue); - if (!skb) { + qlen = skb_queue_len(&sd->input_pkt_queue); + if (qlen) { + input_queue_head_add(sd, qlen); + skb_queue_splice_tail_init(&sd->input_pkt_queue, + &sd->process_queue); + } + if (qlen < quota - work) { __napi_complete(napi); - rps_unlock(sd); - local_irq_enable(); - break; + quota = work + qlen; } - input_queue_head_incr(sd); rps_unlock(sd); - local_irq_enable(); - - __netif_receive_skb(skb); - } while (++work < quota); + } + local_irq_enable(); return work; } @@ -5630,8 +5648,10 @@ static int dev_cpu_callback(struct notifier_block *nfb, /* Process offline CPU's input_pkt_queue */ while ((skb = __skb_dequeue(&oldsd->input_pkt_queue))) { netif_rx(skb); - input_queue_head_incr(oldsd); + input_queue_head_add(oldsd, 1); } + while ((skb = __skb_dequeue(&oldsd->process_queue))) + netif_rx(skb); return NOTIFY_OK; } @@ -5850,6 +5870,7 @@ static int __init net_dev_init(void) struct softnet_data *sd = &per_cpu(softnet_data, i); skb_queue_head_init(&sd->input_pkt_queue); + skb_queue_head_init(&sd->process_queue); sd->completion_queue = NULL; INIT_LIST_HEAD(&sd->poll_list); sd->output_queue = NULL; |