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author | Alexander Duyck <alexander.h.duyck@intel.com> | 2017-04-05 07:51:02 -0400 |
---|---|---|
committer | Jeff Kirsher <jeffrey.t.kirsher@intel.com> | 2017-04-08 02:53:51 -0700 |
commit | ca9ec0888d631c446040a7fab9985afdeb4f73f3 (patch) | |
tree | 8d3039c50ecfee4389540c2c427f918f616b9987 /drivers/net/ethernet/intel/i40e/i40e_txrx.h | |
parent | i40e/i40evf: Add support for using order 1 pages with a 3K buffer (diff) | |
download | linux-dev-ca9ec0888d631c446040a7fab9985afdeb4f73f3.tar.xz linux-dev-ca9ec0888d631c446040a7fab9985afdeb4f73f3.zip |
i40e/i40evf: Add support for padding start of frames
This patch adds padding to the start of frames to make room for headroom
for us to eventually start using build_skb. Right now we guarantee at
least NET_SKB_PAD + NET_IP_ALIGN, however we allocate more space if more is
available. For example on x86 the headroom should be 192 bytes.
On systems that have too large of a cache line size to support storing 1.5K
padding and shared info we default to using 3K buffers and reserve
everything that isn't used for skb_shared_info or the data buffer for
headroom.
Change-ID: I33c641c9a1ea10cf7cc484c2d20985368d2d709a
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Diffstat (limited to 'drivers/net/ethernet/intel/i40e/i40e_txrx.h')
-rw-r--r-- | drivers/net/ethernet/intel/i40e/i40e_txrx.h | 70 |
1 files changed, 69 insertions, 1 deletions
diff --git a/drivers/net/ethernet/intel/i40e/i40e_txrx.h b/drivers/net/ethernet/intel/i40e/i40e_txrx.h index 2f618539a436..f5de51124cae 100644 --- a/drivers/net/ethernet/intel/i40e/i40e_txrx.h +++ b/drivers/net/ethernet/intel/i40e/i40e_txrx.h @@ -135,6 +135,58 @@ enum i40e_dyn_idx_t { #define I40E_RX_DMA_ATTR \ (DMA_ATTR_SKIP_CPU_SYNC | DMA_ATTR_WEAK_ORDERING) +/* Attempt to maximize the headroom available for incoming frames. We + * use a 2K buffer for receives and need 1536/1534 to store the data for + * the frame. This leaves us with 512 bytes of room. From that we need + * to deduct the space needed for the shared info and the padding needed + * to IP align the frame. + * + * Note: For cache line sizes 256 or larger this value is going to end + * up negative. In these cases we should fall back to the legacy + * receive path. + */ +#if (PAGE_SIZE < 8192) +#define I40E_2K_TOO_SMALL_WITH_PADDING \ +((NET_SKB_PAD + I40E_RXBUFFER_1536) > SKB_WITH_OVERHEAD(I40E_RXBUFFER_2048)) + +static inline int i40e_compute_pad(int rx_buf_len) +{ + int page_size, pad_size; + + page_size = ALIGN(rx_buf_len, PAGE_SIZE / 2); + pad_size = SKB_WITH_OVERHEAD(page_size) - rx_buf_len; + + return pad_size; +} + +static inline int i40e_skb_pad(void) +{ + int rx_buf_len; + + /* If a 2K buffer cannot handle a standard Ethernet frame then + * optimize padding for a 3K buffer instead of a 1.5K buffer. + * + * For a 3K buffer we need to add enough padding to allow for + * tailroom due to NET_IP_ALIGN possibly shifting us out of + * cache-line alignment. + */ + if (I40E_2K_TOO_SMALL_WITH_PADDING) + rx_buf_len = I40E_RXBUFFER_3072 + SKB_DATA_ALIGN(NET_IP_ALIGN); + else + rx_buf_len = I40E_RXBUFFER_1536; + + /* if needed make room for NET_IP_ALIGN */ + rx_buf_len -= NET_IP_ALIGN; + + return i40e_compute_pad(rx_buf_len); +} + +#define I40E_SKB_PAD i40e_skb_pad() +#else +#define I40E_2K_TOO_SMALL_WITH_PADDING false +#define I40E_SKB_PAD (NET_SKB_PAD + NET_IP_ALIGN) +#endif + /** * i40e_test_staterr - tests bits in Rx descriptor status and error fields * @rx_desc: pointer to receive descriptor (in le64 format) @@ -341,7 +393,8 @@ struct i40e_ring { u8 packet_stride; u16 flags; -#define I40E_TXR_FLAGS_WB_ON_ITR BIT(0) +#define I40E_TXR_FLAGS_WB_ON_ITR BIT(0) +#define I40E_RXR_FLAGS_BUILD_SKB_ENABLED BIT(1) /* stats structs */ struct i40e_queue_stats stats; @@ -369,6 +422,21 @@ struct i40e_ring { */ } ____cacheline_internodealigned_in_smp; +static inline bool ring_uses_build_skb(struct i40e_ring *ring) +{ + return !!(ring->flags & I40E_RXR_FLAGS_BUILD_SKB_ENABLED); +} + +static inline void set_ring_build_skb_enabled(struct i40e_ring *ring) +{ + ring->flags |= I40E_RXR_FLAGS_BUILD_SKB_ENABLED; +} + +static inline void clear_ring_build_skb_enabled(struct i40e_ring *ring) +{ + ring->flags &= ~I40E_RXR_FLAGS_BUILD_SKB_ENABLED; +} + enum i40e_latency_range { I40E_LOWEST_LATENCY = 0, I40E_LOW_LATENCY = 1, |