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Message-ID: <20140608155941.GL5219@cpaasch-mac>
Date: Sun, 8 Jun 2014 17:59:41 +0200
From: Christoph Paasch <christoph.paasch@...ouvain.be>
To: Octavian Purdila <octavian.purdila@...el.com>
Cc: "netdev@...r.kernel.org" <netdev@...r.kernel.org>
Subject: Re: [PATCH net-next] net: add skb allocation flags to __pskb_copy
Hello Octavian,
On 07/06/14 - 22:19:29, Octavian Purdila wrote:
> There are several instances where a __pskb_copy is immediately
> followed by an skb_clone. Add a new parameter to __pskb_copy to allow
> the skb to be allocated from the fclone cache and thus speed up
> subsequent skb_clone calls.
>
> Signed-off-by: Octavian Purdila <octavian.purdila@...el.com>
> ---
> include/linux/skbuff.h | 6 +++---
> net/bluetooth/hci_sock.c | 5 +++--
> net/core/skbuff.c | 7 +++++--
> net/ipv4/tcp_output.c | 2 +-
> net/nfc/llcp_core.c | 2 +-
> net/nfc/rawsock.c | 2 +-
> 6 files changed, 14 insertions(+), 10 deletions(-)
I found two more cases where the stack could benefit from using an FCLONE:
* batadv_nc_skb_store_before_coding() does a pskb_copy and later in
batadv_nc_skb_store_for_decoding() the skb_clone is done.
* tipc_bcbearer_send() also does a pskb_copy, and the send_msg-callback (in
tipc_bearer_send()) does a clone too later on in tipc_l2_send_msg().
Cheers,
Christoph
>
> diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
> index c705808..7c5b56a 100644
> --- a/include/linux/skbuff.h
> +++ b/include/linux/skbuff.h
> @@ -744,8 +744,8 @@ struct sk_buff *skb_morph(struct sk_buff *dst, struct sk_buff *src);
> int skb_copy_ubufs(struct sk_buff *skb, gfp_t gfp_mask);
> struct sk_buff *skb_clone(struct sk_buff *skb, gfp_t priority);
> struct sk_buff *skb_copy(const struct sk_buff *skb, gfp_t priority);
> -struct sk_buff *__pskb_copy(struct sk_buff *skb, int headroom, gfp_t gfp_mask);
> -
> +struct sk_buff *__pskb_copy(struct sk_buff *skb, int headroom, gfp_t gfp_mask,
> + int flags);
> int pskb_expand_head(struct sk_buff *skb, int nhead, int ntail, gfp_t gfp_mask);
> struct sk_buff *skb_realloc_headroom(struct sk_buff *skb,
> unsigned int headroom);
> @@ -2235,7 +2235,7 @@ static inline dma_addr_t skb_frag_dma_map(struct device *dev,
> static inline struct sk_buff *pskb_copy(struct sk_buff *skb,
> gfp_t gfp_mask)
> {
> - return __pskb_copy(skb, skb_headroom(skb), gfp_mask);
> + return __pskb_copy(skb, skb_headroom(skb), gfp_mask, 0);
> }
>
> /**
> diff --git a/net/bluetooth/hci_sock.c b/net/bluetooth/hci_sock.c
> index f608bff..c2f5db3 100644
> --- a/net/bluetooth/hci_sock.c
> +++ b/net/bluetooth/hci_sock.c
> @@ -143,7 +143,8 @@ void hci_send_to_sock(struct hci_dev *hdev, struct sk_buff *skb)
>
> if (!skb_copy) {
> /* Create a private copy with headroom */
> - skb_copy = __pskb_copy(skb, 1, GFP_ATOMIC);
> + skb_copy = __pskb_copy(skb, 1, GFP_ATOMIC,
> + SKB_ALLOC_FCLONE);
> if (!skb_copy)
> continue;
>
> @@ -248,7 +249,7 @@ void hci_send_to_monitor(struct hci_dev *hdev, struct sk_buff *skb)
>
> /* Create a private copy with headroom */
> skb_copy = __pskb_copy(skb, HCI_MON_HDR_SIZE,
> - GFP_ATOMIC);
> + GFP_ATOMIC, SKB_ALLOC_FCLONE);
> if (!skb_copy)
> continue;
>
> diff --git a/net/core/skbuff.c b/net/core/skbuff.c
> index 05f4bef..03863be 100644
> --- a/net/core/skbuff.c
> +++ b/net/core/skbuff.c
> @@ -955,6 +955,7 @@ EXPORT_SYMBOL(skb_copy);
> * @skb: buffer to copy
> * @headroom: headroom of new skb
> * @gfp_mask: allocation priority
> + * @flags: skb allocation flags (e.g. SKB_ALLOC_FCLONE)
> *
> * Make a copy of both an &sk_buff and part of its data, located
> * in header. Fragmented data remain shared. This is used when
> @@ -964,11 +965,13 @@ EXPORT_SYMBOL(skb_copy);
> * The returned buffer has a reference count of 1.
> */
>
> -struct sk_buff *__pskb_copy(struct sk_buff *skb, int headroom, gfp_t gfp_mask)
> +struct sk_buff *__pskb_copy(struct sk_buff *skb, int headroom, gfp_t gfp_mask,
> + int flags)
> {
> unsigned int size = skb_headlen(skb) + headroom;
> struct sk_buff *n = __alloc_skb(size, gfp_mask,
> - skb_alloc_rx_flag(skb), NUMA_NO_NODE);
> + flags | skb_alloc_rx_flag(skb),
> + NUMA_NO_NODE);
>
> if (!n)
> goto out;
> diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
> index d463c35..17fe18d 100644
> --- a/net/ipv4/tcp_output.c
> +++ b/net/ipv4/tcp_output.c
> @@ -2490,7 +2490,7 @@ int __tcp_retransmit_skb(struct sock *sk, struct sk_buff *skb)
> if (unlikely((NET_IP_ALIGN && ((unsigned long)skb->data & 3)) ||
> skb_headroom(skb) >= 0xFFFF)) {
> struct sk_buff *nskb = __pskb_copy(skb, MAX_TCP_HEADER,
> - GFP_ATOMIC);
> + GFP_ATOMIC, 0);
> err = nskb ? tcp_transmit_skb(sk, nskb, 0, GFP_ATOMIC) :
> -ENOBUFS;
> } else {
> diff --git a/net/nfc/llcp_core.c b/net/nfc/llcp_core.c
> index f6278da..df960a3 100644
> --- a/net/nfc/llcp_core.c
> +++ b/net/nfc/llcp_core.c
> @@ -681,7 +681,7 @@ void nfc_llcp_send_to_raw_sock(struct nfc_llcp_local *local,
>
> if (skb_copy == NULL) {
> skb_copy = __pskb_copy(skb, NFC_RAW_HEADER_SIZE,
> - GFP_ATOMIC);
> + GFP_ATOMIC, SKB_ALLOC_FCLONE);
>
> if (skb_copy == NULL)
> continue;
> diff --git a/net/nfc/rawsock.c b/net/nfc/rawsock.c
> index 55eefee..e8c1805 100644
> --- a/net/nfc/rawsock.c
> +++ b/net/nfc/rawsock.c
> @@ -379,7 +379,7 @@ void nfc_send_to_raw_sock(struct nfc_dev *dev, struct sk_buff *skb,
> sk_for_each(sk, &raw_sk_list.head) {
> if (!skb_copy) {
> skb_copy = __pskb_copy(skb, NFC_RAW_HEADER_SIZE,
> - GFP_ATOMIC);
> + GFP_ATOMIC, SKB_ALLOC_FCLONE);
> if (!skb_copy)
> continue;
>
> --
> 1.8.3.2
>
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