Commit 9243adfc authored by Alexander Lobakin's avatar Alexander Lobakin Committed by David S. Miller
Browse files

skbuff: queue NAPI_MERGED_FREE skbs into NAPI cache instead of freeing 



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: default avatarAlexander Lobakin <alobakin@pm.me>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent cfb8ec65

include/linux/skbuff.h

+1 −0
Original line number Diff line number Diff line
@@ -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);



/**

net/core/dev.c

+1 −8
Original line number Diff line number Diff line
@@ -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:

net/core/skbuff.c

+9 −3
Original line number Diff line number Diff line
@@ -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);