diff options
Diffstat (limited to 'drivers/net/xen-netback')
| -rw-r--r-- | drivers/net/xen-netback/netback.c | 36 |
1 files changed, 25 insertions, 11 deletions
diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c index 7367208ee8cd..a160b4ef5ba0 100644 --- a/drivers/net/xen-netback/netback.c +++ b/drivers/net/xen-netback/netback.c @@ -163,7 +163,8 @@ bool xenvif_rx_ring_slots_available(struct xenvif *vif, int needed) * adding 'size' bytes to a buffer which currently contains 'offset' * bytes. */ -static bool start_new_rx_buffer(int offset, unsigned long size, int head) +static bool start_new_rx_buffer(int offset, unsigned long size, int head, + bool full_coalesce) { /* simple case: we have completely filled the current buffer. */ if (offset == MAX_BUFFER_OFFSET) @@ -175,6 +176,7 @@ static bool start_new_rx_buffer(int offset, unsigned long size, int head) * (i) this frag would fit completely in the next buffer * and (ii) there is already some data in the current buffer * and (iii) this is not the head buffer. + * and (iv) there is no need to fully utilize the buffers * * Where: * - (i) stops us splitting a frag into two copies @@ -185,6 +187,8 @@ static bool start_new_rx_buffer(int offset, unsigned long size, int head) * by (ii) but is explicitly checked because * netfront relies on the first buffer being * non-empty and can crash otherwise. + * - (iv) is needed for skbs which can use up more than MAX_SKB_FRAGS + * slot * * This means we will effectively linearise small * frags but do not needlessly split large buffers @@ -192,7 +196,8 @@ static bool start_new_rx_buffer(int offset, unsigned long size, int head) * own buffers as before. */ BUG_ON(size > MAX_BUFFER_OFFSET); - if ((offset + size > MAX_BUFFER_OFFSET) && offset && !head) + if ((offset + size > MAX_BUFFER_OFFSET) && offset && !head && + !full_coalesce) return true; return false; @@ -227,6 +232,13 @@ static struct xenvif_rx_meta *get_next_rx_buffer(struct xenvif *vif, return meta; } +struct xenvif_rx_cb { + int meta_slots_used; + bool full_coalesce; +}; + +#define XENVIF_RX_CB(skb) ((struct xenvif_rx_cb *)(skb)->cb) + /* * Set up the grant operations for this fragment. If it's a flipping * interface, we also set up the unmap request from here. @@ -261,7 +273,10 @@ static void xenvif_gop_frag_copy(struct xenvif *vif, struct sk_buff *skb, if (bytes > size) bytes = size; - if (start_new_rx_buffer(npo->copy_off, bytes, *head)) { + if (start_new_rx_buffer(npo->copy_off, + bytes, + *head, + XENVIF_RX_CB(skb)->full_coalesce)) { /* * Netfront requires there to be some data in the head * buffer. @@ -541,12 +556,6 @@ static void xenvif_add_frag_responses(struct xenvif *vif, int status, } } -struct xenvif_rx_cb { - int meta_slots_used; -}; - -#define XENVIF_RX_CB(skb) ((struct xenvif_rx_cb *)(skb)->cb) - void xenvif_kick_thread(struct xenvif *vif) { wake_up(&vif->wq); @@ -602,10 +611,15 @@ static void xenvif_rx_action(struct xenvif *vif) /* To avoid the estimate becoming too pessimal for some * frontends that limit posted rx requests, cap the estimate - * at MAX_SKB_FRAGS. + * at MAX_SKB_FRAGS. In this case netback will fully coalesce + * the skb into the provided slots. */ - if (max_slots_needed > MAX_SKB_FRAGS) + if (max_slots_needed > MAX_SKB_FRAGS) { max_slots_needed = MAX_SKB_FRAGS; + XENVIF_RX_CB(skb)->full_coalesce = true; + } else { + XENVIF_RX_CB(skb)->full_coalesce = false; + } /* We may need one more slot for GSO metadata */ if (skb_is_gso(skb) && |