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skbuff: queue NAPI_MERGED_FREE skbs into NAPI cache instead of freeing

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napi_frags_finish() and napi_skb_finish() can only be called inside
NAPI Rx context, so we can feed NAPI cache with skbuff_heads that
got NAPI_MERGED_FREE verdict instead of immediate freeing.
Replace __kfree_skb() with __kfree_skb_defer() in napi_skb_finish()
and move napi_skb_free_stolen_head() to skbuff.c, so it can drop skbs
to NAPI cache.
As many drivers call napi_alloc_skb()/napi_get_frags() on their
receive path, this becomes especially useful.

Signed-off-by: Alexander Lobakin <alobakin@pm.me>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Alexander Lobakin 2021-02-13 14:13:09 +00:00 committed by David S. Miller
parent cfb8ec6595
commit 9243adfc31
3 changed files with 11 additions and 11 deletions
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1
include/linux/skbuff.h
View File

@ -2921,6 +2921,7 @@ static inline struct sk_buff *napi_alloc_skb(struct napi_struct *napi,
}
void napi_consume_skb(struct sk_buff *skb, int budget);
void napi_skb_free_stolen_head(struct sk_buff *skb);
void __kfree_skb_defer(struct sk_buff *skb);
/**

9
net/core/dev.c
View File

@ -6095,13 +6095,6 @@ struct packet_offload *gro_find_complete_by_type(__be16 type)
}
EXPORT_SYMBOL(gro_find_complete_by_type);
static void napi_skb_free_stolen_head(struct sk_buff *skb)
{
skb_dst_drop(skb);
skb_ext_put(skb);
kmem_cache_free(skbuff_head_cache, skb);
}
static gro_result_t napi_skb_finish(struct napi_struct *napi,
struct sk_buff *skb,
gro_result_t ret)
@ -6115,7 +6108,7 @@ static gro_result_t napi_skb_finish(struct napi_struct *napi,
if (NAPI_GRO_CB(skb)->free == NAPI_GRO_FREE_STOLEN_HEAD)
napi_skb_free_stolen_head(skb);
else
__kfree_skb(skb);
__kfree_skb_defer(skb);
break;
case GRO_HELD:

12
net/core/skbuff.c
View File

@ -916,9 +916,6 @@ static void napi_skb_cache_put(struct sk_buff *skb)
struct napi_alloc_cache *nc = this_cpu_ptr(&napi_alloc_cache);
u32 i;
/* drop skb->head and call any destructors for packet */
skb_release_all(skb);
kasan_poison_object_data(skbuff_head_cache, skb);
nc->skb_cache[nc->skb_count++] = skb;
@ -935,6 +932,14 @@ static void napi_skb_cache_put(struct sk_buff *skb)
void __kfree_skb_defer(struct sk_buff *skb)
{
skb_release_all(skb);
napi_skb_cache_put(skb);
}
void napi_skb_free_stolen_head(struct sk_buff *skb)
{
skb_dst_drop(skb);
skb_ext_put(skb);
napi_skb_cache_put(skb);
}
@ -960,6 +965,7 @@ void napi_consume_skb(struct sk_buff *skb, int budget)
return;
}
skb_release_all(skb);
napi_skb_cache_put(skb);
}
EXPORT_SYMBOL(napi_consume_skb);