From ca9ec0888d631c446040a7fab9985afdeb4f73f3 Mon Sep 17 00:00:00 2001 From: Alexander Duyck Date: Wed, 5 Apr 2017 07:51:02 -0400 Subject: [PATCH] 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 Tested-by: Andrew Bowers Signed-off-by: Jeff Kirsher --- drivers/net/ethernet/intel/i40e/i40e_main.c | 9 ++- drivers/net/ethernet/intel/i40e/i40e_txrx.c | 15 +++- drivers/net/ethernet/intel/i40e/i40e_txrx.h | 70 ++++++++++++++++++- drivers/net/ethernet/intel/i40evf/i40e_txrx.c | 15 +++- drivers/net/ethernet/intel/i40evf/i40e_txrx.h | 70 ++++++++++++++++++- .../net/ethernet/intel/i40evf/i40evf_main.c | 8 ++- 6 files changed, 179 insertions(+), 8 deletions(-) diff --git a/drivers/net/ethernet/intel/i40e/i40e_main.c b/drivers/net/ethernet/intel/i40e/i40e_main.c index 97489d69029a..b6ec9beeebff 100644 --- a/drivers/net/ethernet/intel/i40e/i40e_main.c +++ b/drivers/net/ethernet/intel/i40e/i40e_main.c @@ -3038,6 +3038,12 @@ static int i40e_configure_rx_ring(struct i40e_ring *ring) return -ENOMEM; } + /* configure Rx buffer alignment */ + if (!vsi->netdev || (vsi->back->flags & I40E_FLAG_LEGACY_RX)) + clear_ring_build_skb_enabled(ring); + else + set_ring_build_skb_enabled(ring); + /* cache tail for quicker writes, and clear the reg before use */ ring->tail = hw->hw_addr + I40E_QRX_TAIL(pf_q); writel(0, ring->tail); @@ -3079,7 +3085,8 @@ static int i40e_vsi_configure_rx(struct i40e_vsi *vsi) vsi->max_frame = I40E_MAX_RXBUFFER; vsi->rx_buf_len = I40E_RXBUFFER_2048; #if (PAGE_SIZE < 8192) - } else if (vsi->netdev->mtu <= ETH_DATA_LEN) { + } else if (!I40E_2K_TOO_SMALL_WITH_PADDING && + (vsi->netdev->mtu <= ETH_DATA_LEN)) { vsi->max_frame = I40E_RXBUFFER_1536 - NET_IP_ALIGN; vsi->rx_buf_len = I40E_RXBUFFER_1536 - NET_IP_ALIGN; #endif diff --git a/drivers/net/ethernet/intel/i40e/i40e_txrx.c b/drivers/net/ethernet/intel/i40e/i40e_txrx.c index bee16726c104..f15e1bcf3555 100644 --- a/drivers/net/ethernet/intel/i40e/i40e_txrx.c +++ b/drivers/net/ethernet/intel/i40e/i40e_txrx.c @@ -1247,6 +1247,17 @@ static inline void i40e_release_rx_desc(struct i40e_ring *rx_ring, u32 val) writel(val, rx_ring->tail); } +/** + * i40e_rx_offset - Return expected offset into page to access data + * @rx_ring: Ring we are requesting offset of + * + * Returns the offset value for ring into the data buffer. + */ +static inline unsigned int i40e_rx_offset(struct i40e_ring *rx_ring) +{ + return ring_uses_build_skb(rx_ring) ? I40E_SKB_PAD : 0; +} + /** * i40e_alloc_mapped_page - recycle or make a new page * @rx_ring: ring to use @@ -1291,7 +1302,7 @@ static bool i40e_alloc_mapped_page(struct i40e_ring *rx_ring, bi->dma = dma; bi->page = page; - bi->page_offset = 0; + bi->page_offset = i40e_rx_offset(rx_ring); /* initialize pagecnt_bias to 1 representing we fully own page */ bi->pagecnt_bias = 1; @@ -1696,7 +1707,7 @@ static void i40e_add_rx_frag(struct i40e_ring *rx_ring, #if (PAGE_SIZE < 8192) unsigned int truesize = i40e_rx_pg_size(rx_ring) / 2; #else - unsigned int truesize = SKB_DATA_ALIGN(size); + unsigned int truesize = SKB_DATA_ALIGN(size + i40e_rx_offset(rx_ring)); #endif skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags, rx_buffer->page, 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, diff --git a/drivers/net/ethernet/intel/i40evf/i40e_txrx.c b/drivers/net/ethernet/intel/i40evf/i40e_txrx.c index 6b60c19a794b..a71f81a9291f 100644 --- a/drivers/net/ethernet/intel/i40evf/i40e_txrx.c +++ b/drivers/net/ethernet/intel/i40evf/i40e_txrx.c @@ -618,6 +618,17 @@ static inline void i40e_release_rx_desc(struct i40e_ring *rx_ring, u32 val) writel(val, rx_ring->tail); } +/** + * i40e_rx_offset - Return expected offset into page to access data + * @rx_ring: Ring we are requesting offset of + * + * Returns the offset value for ring into the data buffer. + */ +static inline unsigned int i40e_rx_offset(struct i40e_ring *rx_ring) +{ + return ring_uses_build_skb(rx_ring) ? I40E_SKB_PAD : 0; +} + /** * i40e_alloc_mapped_page - recycle or make a new page * @rx_ring: ring to use @@ -662,7 +673,7 @@ static bool i40e_alloc_mapped_page(struct i40e_ring *rx_ring, bi->dma = dma; bi->page = page; - bi->page_offset = 0; + bi->page_offset = i40e_rx_offset(rx_ring); /* initialize pagecnt_bias to 1 representing we fully own page */ bi->pagecnt_bias = 1; @@ -1057,7 +1068,7 @@ static void i40e_add_rx_frag(struct i40e_ring *rx_ring, #if (PAGE_SIZE < 8192) unsigned int truesize = i40e_rx_pg_size(rx_ring) / 2; #else - unsigned int truesize = SKB_DATA_ALIGN(size); + unsigned int truesize = SKB_DATA_ALIGN(size + i40e_rx_offset(rx_ring)); #endif skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags, rx_buffer->page, diff --git a/drivers/net/ethernet/intel/i40evf/i40e_txrx.h b/drivers/net/ethernet/intel/i40evf/i40e_txrx.h index dc82f65267ec..901282c87cf6 100644 --- a/drivers/net/ethernet/intel/i40evf/i40e_txrx.h +++ b/drivers/net/ethernet/intel/i40evf/i40e_txrx.h @@ -122,6 +122,58 @@ 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) @@ -328,7 +380,8 @@ 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; @@ -356,6 +409,21 @@ 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, diff --git a/drivers/net/ethernet/intel/i40evf/i40evf_main.c b/drivers/net/ethernet/intel/i40evf/i40evf_main.c index 7d00abae6104..12a930e879af 100644 --- a/drivers/net/ethernet/intel/i40evf/i40evf_main.c +++ b/drivers/net/ethernet/intel/i40evf/i40evf_main.c @@ -704,7 +704,8 @@ static void i40evf_configure_rx(struct i40evf_adapter *adapter) * standard Ethernet mtu. On x86 this gives us enough room * for shared info and 192 bytes of padding. */ - if (netdev->mtu <= ETH_DATA_LEN) + if (!I40E_2K_TOO_SMALL_WITH_PADDING && + (netdev->mtu <= ETH_DATA_LEN)) rx_buf_len = I40E_RXBUFFER_1536 - NET_IP_ALIGN; } #endif @@ -712,6 +713,11 @@ static void i40evf_configure_rx(struct i40evf_adapter *adapter) for (i = 0; i < adapter->num_active_queues; i++) { adapter->rx_rings[i].tail = hw->hw_addr + I40E_QRX_TAIL1(i); adapter->rx_rings[i].rx_buf_len = rx_buf_len; + + if (adapter->flags & I40EVF_FLAG_LEGACY_RX) + clear_ring_build_skb_enabled(&adapter->rx_rings[i]); + else + set_ring_build_skb_enabled(&adapter->rx_rings[i]); } } -- 2.20.1