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Merge branch 'gro-micro-optimize-dev_gro_receive'

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Alexander Lobakin says:

====================
gro: micro-optimize dev_gro_receive()

This random series addresses some of suboptimal constructions used
in the main GRO entry point.
The main body is gro_list_prepare() simplification and pointer usage
optimization in dev_gro_receive() itself. Being mostly cosmetic, it
gives like +10 Mbps on my setup to both TCP and UDP (both single- and
multi-flow).

Since v1 [0]:
 - drop the replacement of bucket index calculation with
   reciprocal_scale() since it makes absolutely no sense (Eric);
 - improve stack usage in dev_gro_receive() (Eric);
 - reverse the order of patches to avoid changes superseding.

[0] https://lore.kernel.org/netdev/20210312162127.239795-1-alobakin@pm.me
====================

Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David S. Miller 2021-03-14 14:41:09 -07:00
commit 3f79eb3c3a
1 changed files with 18 additions and 22 deletions
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40
net/core/dev.c
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@ -5858,15 +5858,13 @@ void napi_gro_flush(struct napi_struct *napi, bool flush_old)
}
EXPORT_SYMBOL(napi_gro_flush);
static struct list_head *gro_list_prepare(struct napi_struct *napi,
struct sk_buff *skb)
static void gro_list_prepare(const struct list_head *head,
const struct sk_buff *skb)
{
unsigned int maclen = skb->dev->hard_header_len;
u32 hash = skb_get_hash_raw(skb);
struct list_head *head;
struct sk_buff *p;
head = &napi->gro_hash[hash & (GRO_HASH_BUCKETS - 1)].list;
list_for_each_entry(p, head, list) {
unsigned long diffs;
@ -5892,8 +5890,6 @@ static struct list_head *gro_list_prepare(struct napi_struct *napi,
maclen);
NAPI_GRO_CB(p)->same_flow = !diffs;
}
return head;
}
static void skb_gro_reset_offset(struct sk_buff *skb)
@ -5956,11 +5952,11 @@ static void gro_flush_oldest(struct napi_struct *napi, struct list_head *head)
static enum gro_result dev_gro_receive(struct napi_struct *napi, struct sk_buff *skb)
{
u32 hash = skb_get_hash_raw(skb) & (GRO_HASH_BUCKETS - 1);
u32 bucket = skb_get_hash_raw(skb) & (GRO_HASH_BUCKETS - 1);
struct gro_list *gro_list = &napi->gro_hash[bucket];
struct list_head *head = &offload_base;
struct packet_offload *ptype;
__be16 type = skb->protocol;
struct list_head *gro_head;
struct sk_buff *pp = NULL;
enum gro_result ret;
int same_flow;
@ -5969,7 +5965,7 @@ static enum gro_result dev_gro_receive(struct napi_struct *napi, struct sk_buff
if (netif_elide_gro(skb->dev))
goto normal;
gro_head = gro_list_prepare(napi, skb);
gro_list_prepare(&gro_list->list, skb);
rcu_read_lock();
list_for_each_entry_rcu(ptype, head, list) {
@ -6005,7 +6001,7 @@ static enum gro_result dev_gro_receive(struct napi_struct *napi, struct sk_buff
pp = INDIRECT_CALL_INET(ptype->callbacks.gro_receive,
ipv6_gro_receive, inet_gro_receive,
gro_head, skb);
&gro_list->list, skb);
break;
}
rcu_read_unlock();
@ -6024,7 +6020,7 @@ static enum gro_result dev_gro_receive(struct napi_struct *napi, struct sk_buff
if (pp) {
skb_list_del_init(pp);
napi_gro_complete(napi, pp);
napi->gro_hash[hash].count--;
gro_list->count--;
}
if (same_flow)
@ -6033,16 +6029,16 @@ static enum gro_result dev_gro_receive(struct napi_struct *napi, struct sk_buff
if (NAPI_GRO_CB(skb)->flush)
goto normal;
if (unlikely(napi->gro_hash[hash].count >= MAX_GRO_SKBS)) {
gro_flush_oldest(napi, gro_head);
} else {
napi->gro_hash[hash].count++;
}
if (unlikely(gro_list->count >= MAX_GRO_SKBS))
gro_flush_oldest(napi, &gro_list->list);
else
gro_list->count++;
NAPI_GRO_CB(skb)->count = 1;
NAPI_GRO_CB(skb)->age = jiffies;
NAPI_GRO_CB(skb)->last = skb;
skb_shinfo(skb)->gso_size = skb_gro_len(skb);
list_add(&skb->list, gro_head);
list_add(&skb->list, &gro_list->list);
ret = GRO_HELD;
pull:
@ -6050,11 +6046,11 @@ pull:
if (grow > 0)
gro_pull_from_frag0(skb, grow);
ok:
if (napi->gro_hash[hash].count) {
if (!test_bit(hash, &napi->gro_bitmask))
__set_bit(hash, &napi->gro_bitmask);
} else if (test_bit(hash, &napi->gro_bitmask)) {
__clear_bit(hash, &napi->gro_bitmask);
if (gro_list->count) {
if (!test_bit(bucket, &napi->gro_bitmask))
__set_bit(bucket, &napi->gro_bitmask);
} else if (test_bit(bucket, &napi->gro_bitmask)) {
__clear_bit(bucket, &napi->gro_bitmask);
}
return ret;