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net: Convert NAPI gro list into a small hash table.
Improve the performance of GRO receive by splitting flows into multiple hash chains. Suggested-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David Miller
David S. Miller
parent
d4546c2509
commit
07d78363dc
@ -305,6 +305,7 @@ int __init netdev_boot_setup(char *str);
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/*
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* Structure for NAPI scheduling similar to tasklet but with weighting
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*/
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#define GRO_HASH_BUCKETS 8
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struct napi_struct {
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/* The poll_list must only be managed by the entity which
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* changes the state of the NAPI_STATE_SCHED bit. This means
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@ -322,7 +323,7 @@ struct napi_struct {
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int poll_owner;
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#endif
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struct net_device *dev;
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struct list_head gro_list;
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struct list_head gro_hash[GRO_HASH_BUCKETS];
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struct sk_buff *skb;
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struct hrtimer timer;
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struct list_head dev_list;
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105
net/core/dev.c
105
net/core/dev.c
@ -4875,15 +4875,12 @@ out:
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return netif_receive_skb_internal(skb);
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}
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/* napi->gro_list contains packets ordered by age.
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* youngest packets at the head of it.
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* Complete skbs in reverse order to reduce latencies.
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*/
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void napi_gro_flush(struct napi_struct *napi, bool flush_old)
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static void __napi_gro_flush_chain(struct napi_struct *napi, struct list_head *head,
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bool flush_old)
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{
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struct sk_buff *skb, *p;
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list_for_each_entry_safe_reverse(skb, p, &napi->gro_list, list) {
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list_for_each_entry_safe_reverse(skb, p, head, list) {
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if (flush_old && NAPI_GRO_CB(skb)->age == jiffies)
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return;
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list_del_init(&skb->list);
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@ -4891,15 +4888,33 @@ void napi_gro_flush(struct napi_struct *napi, bool flush_old)
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napi->gro_count--;
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}
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}
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/* napi->gro_hash contains packets ordered by age.
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* youngest packets at the head of it.
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* Complete skbs in reverse order to reduce latencies.
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*/
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void napi_gro_flush(struct napi_struct *napi, bool flush_old)
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{
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int i;
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for (i = 0; i < GRO_HASH_BUCKETS; i++) {
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struct list_head *head = &napi->gro_hash[i];
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__napi_gro_flush_chain(napi, head, flush_old);
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}
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}
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EXPORT_SYMBOL(napi_gro_flush);
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static void gro_list_prepare(struct napi_struct *napi, struct sk_buff *skb)
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static struct list_head *gro_list_prepare(struct napi_struct *napi,
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struct sk_buff *skb)
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{
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unsigned int maclen = skb->dev->hard_header_len;
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u32 hash = skb_get_hash_raw(skb);
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struct list_head *head;
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struct sk_buff *p;
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list_for_each_entry(p, &napi->gro_list, list) {
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head = &napi->gro_hash[hash & (GRO_HASH_BUCKETS - 1)];
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list_for_each_entry(p, head, list) {
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unsigned long diffs;
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NAPI_GRO_CB(p)->flush = 0;
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@ -4922,6 +4937,8 @@ static void gro_list_prepare(struct napi_struct *napi, struct sk_buff *skb)
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maclen);
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NAPI_GRO_CB(p)->same_flow = !diffs;
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}
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return head;
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}
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static void skb_gro_reset_offset(struct sk_buff *skb)
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@ -4964,11 +4981,45 @@ static void gro_pull_from_frag0(struct sk_buff *skb, int grow)
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}
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}
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static void gro_flush_oldest(struct napi_struct *napi)
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{
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struct sk_buff *oldest = NULL;
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unsigned long age = jiffies;
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int i;
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for (i = 0; i < GRO_HASH_BUCKETS; i++) {
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struct list_head *head = &napi->gro_hash[i];
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struct sk_buff *skb;
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if (list_empty(head))
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continue;
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skb = list_last_entry(head, struct sk_buff, list);
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if (!oldest || time_before(NAPI_GRO_CB(skb)->age, age)) {
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oldest = skb;
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age = NAPI_GRO_CB(skb)->age;
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}
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}
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/* We are called with napi->gro_count >= MAX_GRO_SKBS, so this is
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* impossible.
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*/
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if (WARN_ON_ONCE(!oldest))
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return;
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/* Do not adjust napi->gro_count, caller is adding a new SKB to
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* the chain.
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*/
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list_del(&oldest->list);
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napi_gro_complete(oldest);
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}
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static enum gro_result dev_gro_receive(struct napi_struct *napi, struct sk_buff *skb)
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{
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struct list_head *head = &offload_base;
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struct packet_offload *ptype;
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__be16 type = skb->protocol;
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struct list_head *gro_head;
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struct sk_buff *pp = NULL;
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enum gro_result ret;
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int same_flow;
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@ -4977,7 +5028,7 @@ static enum gro_result dev_gro_receive(struct napi_struct *napi, struct sk_buff
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if (netif_elide_gro(skb->dev))
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goto normal;
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gro_list_prepare(napi, skb);
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gro_head = gro_list_prepare(napi, skb);
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rcu_read_lock();
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list_for_each_entry_rcu(ptype, head, list) {
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@ -5011,7 +5062,7 @@ static enum gro_result dev_gro_receive(struct napi_struct *napi, struct sk_buff
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NAPI_GRO_CB(skb)->csum_valid = 0;
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}
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pp = ptype->callbacks.gro_receive(&napi->gro_list, skb);
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pp = ptype->callbacks.gro_receive(gro_head, skb);
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break;
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}
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rcu_read_unlock();
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@ -5040,11 +5091,7 @@ static enum gro_result dev_gro_receive(struct napi_struct *napi, struct sk_buff
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goto normal;
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if (unlikely(napi->gro_count >= MAX_GRO_SKBS)) {
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struct sk_buff *nskb;
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nskb = list_last_entry(&napi->gro_list, struct sk_buff, list);
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list_del(&nskb->list);
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napi_gro_complete(nskb);
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gro_flush_oldest(napi);
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} else {
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napi->gro_count++;
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}
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@ -5052,7 +5099,7 @@ static enum gro_result dev_gro_receive(struct napi_struct *napi, struct sk_buff
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NAPI_GRO_CB(skb)->age = jiffies;
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NAPI_GRO_CB(skb)->last = skb;
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skb_shinfo(skb)->gso_size = skb_gro_len(skb);
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list_add(&skb->list, &napi->gro_list);
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list_add(&skb->list, gro_head);
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ret = GRO_HELD;
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pull:
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@ -5458,7 +5505,7 @@ bool napi_complete_done(struct napi_struct *n, int work_done)
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NAPIF_STATE_IN_BUSY_POLL)))
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return false;
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if (!list_empty(&n->gro_list)) {
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if (n->gro_count) {
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unsigned long timeout = 0;
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if (work_done)
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@ -5667,7 +5714,7 @@ static enum hrtimer_restart napi_watchdog(struct hrtimer *timer)
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/* Note : we use a relaxed variant of napi_schedule_prep() not setting
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* NAPI_STATE_MISSED, since we do not react to a device IRQ.
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*/
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if (!list_empty(&napi->gro_list) && !napi_disable_pending(napi) &&
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if (napi->gro_count && !napi_disable_pending(napi) &&
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!test_and_set_bit(NAPI_STATE_SCHED, &napi->state))
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__napi_schedule_irqoff(napi);
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@ -5677,11 +5724,14 @@ static enum hrtimer_restart napi_watchdog(struct hrtimer *timer)
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void netif_napi_add(struct net_device *dev, struct napi_struct *napi,
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int (*poll)(struct napi_struct *, int), int weight)
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{
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int i;
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INIT_LIST_HEAD(&napi->poll_list);
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hrtimer_init(&napi->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_PINNED);
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napi->timer.function = napi_watchdog;
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napi->gro_count = 0;
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INIT_LIST_HEAD(&napi->gro_list);
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for (i = 0; i < GRO_HASH_BUCKETS; i++)
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INIT_LIST_HEAD(&napi->gro_hash[i]);
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napi->skb = NULL;
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napi->poll = poll;
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if (weight > NAPI_POLL_WEIGHT)
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@ -5714,12 +5764,16 @@ void napi_disable(struct napi_struct *n)
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}
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EXPORT_SYMBOL(napi_disable);
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static void gro_list_free(struct list_head *head)
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static void flush_gro_hash(struct napi_struct *napi)
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{
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struct sk_buff *skb, *p;
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int i;
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list_for_each_entry_safe(skb, p, head, list)
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kfree_skb(skb);
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for (i = 0; i < GRO_HASH_BUCKETS; i++) {
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struct sk_buff *skb, *n;
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list_for_each_entry_safe(skb, n, &napi->gro_hash[i], list)
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kfree_skb(skb);
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}
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}
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/* Must be called in process context */
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@ -5731,8 +5785,7 @@ void netif_napi_del(struct napi_struct *napi)
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list_del_init(&napi->dev_list);
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napi_free_frags(napi);
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gro_list_free(&napi->gro_list);
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INIT_LIST_HEAD(&napi->gro_list);
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flush_gro_hash(napi);
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napi->gro_count = 0;
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}
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EXPORT_SYMBOL(netif_napi_del);
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@ -5775,7 +5828,7 @@ static int napi_poll(struct napi_struct *n, struct list_head *repoll)
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goto out_unlock;
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}
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if (!list_empty(&n->gro_list)) {
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if (n->gro_count) {
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/* flush too old packets
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* If HZ < 1000, flush all packets.
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*/
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