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| author | David Vrabel <david.vrabel@citrix.com> | 2016-10-04 12:29:14 +0300 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2016-10-07 03:37:35 +0300 |
| commit | eb1723a29b9a75dd787510a39096a68dba6cc200 (patch) | |
| tree | 7f6c52ddcb5b98accb591c01b94def17d100007e /drivers/net/xen-netback/common.h | |
| parent | fedbc8c132bcf836358103195d8b6df6c03d9daf (diff) | |
| download | linux-eb1723a29b9a75dd787510a39096a68dba6cc200.tar.xz | |
xen-netback: refactor guest rx
Refactor the to-guest (rx) path to:
1. Push responses for completed skbs earlier, reducing latency.
2. Reduce the per-queue memory overhead by greatly reducing the
maximum number of grant copy ops in each hypercall (from 4352 to
64). Each struct xenvif_queue is now only 44 kB instead of 220 kB.
3. Make the code more maintainable.
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
[re-based]
Signed-off-by: Paul Durrant <paul.durrant@citrix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net/xen-netback/common.h')
| -rw-r--r-- | drivers/net/xen-netback/common.h | 23 |
1 files changed, 10 insertions, 13 deletions
diff --git a/drivers/net/xen-netback/common.h b/drivers/net/xen-netback/common.h index 0ba59106b1a5..7d12a388afc6 100644 --- a/drivers/net/xen-netback/common.h +++ b/drivers/net/xen-netback/common.h @@ -91,13 +91,6 @@ struct xenvif_rx_meta { */ #define MAX_XEN_SKB_FRAGS (65536 / XEN_PAGE_SIZE + 1) -/* It's possible for an skb to have a maximal number of frags - * but still be less than MAX_BUFFER_OFFSET in size. Thus the - * worst-case number of copy operations is MAX_XEN_SKB_FRAGS per - * ring slot. - */ -#define MAX_GRANT_COPY_OPS (MAX_XEN_SKB_FRAGS * XEN_NETIF_RX_RING_SIZE) - #define NETBACK_INVALID_HANDLE -1 /* To avoid confusion, we define XEN_NETBK_LEGACY_SLOTS_MAX indicating @@ -133,6 +126,14 @@ struct xenvif_stats { unsigned long tx_frag_overflow; }; +#define COPY_BATCH_SIZE 64 + +struct xenvif_copy_state { + struct gnttab_copy op[COPY_BATCH_SIZE]; + RING_IDX idx[COPY_BATCH_SIZE]; + unsigned int num; +}; + struct xenvif_queue { /* Per-queue data for xenvif */ unsigned int id; /* Queue ID, 0-based */ char name[QUEUE_NAME_SIZE]; /* DEVNAME-qN */ @@ -189,12 +190,7 @@ struct xenvif_queue { /* Per-queue data for xenvif */ unsigned long last_rx_time; bool stalled; - struct gnttab_copy grant_copy_op[MAX_GRANT_COPY_OPS]; - - /* We create one meta structure per ring request we consume, so - * the maximum number is the same as the ring size. - */ - struct xenvif_rx_meta meta[XEN_NETIF_RX_RING_SIZE]; + struct xenvif_copy_state rx_copy; /* Transmit shaping: allow 'credit_bytes' every 'credit_usec'. */ unsigned long credit_bytes; @@ -358,6 +354,7 @@ int xenvif_dealloc_kthread(void *data); irqreturn_t xenvif_ctrl_irq_fn(int irq, void *data); +void xenvif_rx_action(struct xenvif_queue *queue); void xenvif_rx_queue_tail(struct xenvif_queue *queue, struct sk_buff *skb); void xenvif_carrier_on(struct xenvif *vif); |