From: Alexander Duyck Date: Tue, 17 Jan 2017 16:36:45 +0000 (-0800) Subject: ixgbe: Break out Rx buffer page management X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=3fd218767fa49857e812e53a27fcbf5d24d040d6;p=openwrt%2Fstaging%2Fblogic.git ixgbe: Break out Rx buffer page management We are going to be expanding the number of Rx paths in the driver. Instead of duplicating all that code I am pulling it apart into separate functions so that we don't have so much code duplication. Signed-off-by: Alexander Duyck Tested-by: Andrew Bowers Signed-off-by: Jeff Kirsher --- diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c index 6fc26cdacba2..1e5575305f2a 100644 --- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c +++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c @@ -1847,7 +1847,6 @@ static void ixgbe_dma_sync_frag(struct ixgbe_ring *rx_ring, ixgbe_rx_pg_size(rx_ring), DMA_FROM_DEVICE, IXGBE_RX_DMA_ATTR); - IXGBE_CB(skb)->page_released = false; } else { struct skb_frag_struct *frag = &skb_shinfo(skb)->frags[0]; @@ -1857,7 +1856,6 @@ static void ixgbe_dma_sync_frag(struct ixgbe_ring *rx_ring, skb_frag_size(frag), DMA_FROM_DEVICE); } - IXGBE_CB(skb)->dma = 0; } /** @@ -1928,8 +1926,14 @@ static void ixgbe_reuse_rx_page(struct ixgbe_ring *rx_ring, nta++; rx_ring->next_to_alloc = (nta < rx_ring->count) ? nta : 0; - /* transfer page from old buffer to new buffer */ - *new_buff = *old_buff; + /* Transfer page from old buffer to new buffer. + * Move each member individually to avoid possible store + * forwarding stalls and unnecessary copy of skb. + */ + new_buff->dma = old_buff->dma; + new_buff->page = old_buff->page; + new_buff->page_offset = old_buff->page_offset; + new_buff->pagecnt_bias = old_buff->pagecnt_bias; } static inline bool ixgbe_page_is_reserved(struct page *page) @@ -1937,16 +1941,10 @@ static inline bool ixgbe_page_is_reserved(struct page *page) return (page_to_nid(page) != numa_mem_id()) || page_is_pfmemalloc(page); } -static bool ixgbe_can_reuse_rx_page(struct ixgbe_ring *rx_ring, - struct ixgbe_rx_buffer *rx_buffer, - struct page *page, - const unsigned int truesize) +static bool ixgbe_can_reuse_rx_page(struct ixgbe_rx_buffer *rx_buffer) { -#if (PAGE_SIZE >= 8192) - unsigned int last_offset = ixgbe_rx_pg_size(rx_ring) - - ixgbe_rx_bufsz(rx_ring); -#endif - unsigned int pagecnt_bias = rx_buffer->pagecnt_bias--; + unsigned int pagecnt_bias = rx_buffer->pagecnt_bias; + struct page *page = rx_buffer->page; /* avoid re-using remote pages */ if (unlikely(ixgbe_page_is_reserved(page))) @@ -1954,16 +1952,17 @@ static bool ixgbe_can_reuse_rx_page(struct ixgbe_ring *rx_ring, #if (PAGE_SIZE < 8192) /* if we are only owner of page we can reuse it */ - if (unlikely(page_count(page) != pagecnt_bias)) + if (unlikely((page_ref_count(page) - pagecnt_bias) > 1)) return false; - - /* flip page offset to other buffer */ - rx_buffer->page_offset ^= truesize; #else - /* move offset up to the next cache line */ - rx_buffer->page_offset += truesize; - - if (rx_buffer->page_offset > last_offset) + /* The last offset is a bit aggressive in that we assume the + * worst case of FCoE being enabled and using a 3K buffer. + * However this should have minimal impact as the 1K extra is + * still less than one buffer in size. + */ +#define IXGBE_LAST_OFFSET \ + (SKB_WITH_OVERHEAD(PAGE_SIZE) - IXGBE_RXBUFFER_3K) + if (rx_buffer->page_offset > IXGBE_LAST_OFFSET) return false; #endif @@ -1971,7 +1970,7 @@ static bool ixgbe_can_reuse_rx_page(struct ixgbe_ring *rx_ring, * the pagecnt_bias and page count so that we fully restock the * number of references the driver holds. */ - if (unlikely(pagecnt_bias == 1)) { + if (unlikely(!pagecnt_bias)) { page_ref_add(page, USHRT_MAX); rx_buffer->pagecnt_bias = USHRT_MAX; } @@ -1994,106 +1993,65 @@ static bool ixgbe_can_reuse_rx_page(struct ixgbe_ring *rx_ring, * The function will then update the page offset if necessary and return * true if the buffer can be reused by the adapter. **/ -static bool ixgbe_add_rx_frag(struct ixgbe_ring *rx_ring, +static void ixgbe_add_rx_frag(struct ixgbe_ring *rx_ring, struct ixgbe_rx_buffer *rx_buffer, - unsigned int size, - struct sk_buff *skb) + struct sk_buff *skb, + unsigned int size) { - struct page *page = rx_buffer->page; - unsigned char *va = page_address(page) + rx_buffer->page_offset; #if (PAGE_SIZE < 8192) unsigned int truesize = ixgbe_rx_pg_size(rx_ring) / 2; #else unsigned int truesize = SKB_DATA_ALIGN(size); #endif - - if (unlikely(skb_is_nonlinear(skb))) - goto add_tail_frag; - - if (size <= IXGBE_RX_HDR_SIZE) { - memcpy(__skb_put(skb, size), va, ALIGN(size, sizeof(long))); - - /* page is not reserved, we can reuse buffer as-is */ - if (likely(!ixgbe_page_is_reserved(page))) - return true; - - /* this page cannot be reused so discard it */ - return false; - } - -add_tail_frag: - skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags, page, + skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags, rx_buffer->page, rx_buffer->page_offset, size, truesize); - - return ixgbe_can_reuse_rx_page(rx_ring, rx_buffer, page, truesize); +#if (PAGE_SIZE < 8192) + rx_buffer->page_offset ^= truesize; +#else + rx_buffer->page_offset += truesize; +#endif } -static struct sk_buff *ixgbe_fetch_rx_buffer(struct ixgbe_ring *rx_ring, - union ixgbe_adv_rx_desc *rx_desc) +static struct ixgbe_rx_buffer *ixgbe_get_rx_buffer(struct ixgbe_ring *rx_ring, + union ixgbe_adv_rx_desc *rx_desc, + struct sk_buff **skb, + const unsigned int size) { - unsigned int size = le16_to_cpu(rx_desc->wb.upper.length); struct ixgbe_rx_buffer *rx_buffer; - struct sk_buff *skb; - struct page *page; rx_buffer = &rx_ring->rx_buffer_info[rx_ring->next_to_clean]; - page = rx_buffer->page; - prefetchw(page); - - skb = rx_buffer->skb; - - if (likely(!skb)) { - void *page_addr = page_address(page) + - rx_buffer->page_offset; + prefetchw(rx_buffer->page); + *skb = rx_buffer->skb; - /* prefetch first cache line of first page */ - prefetch(page_addr); -#if L1_CACHE_BYTES < 128 - prefetch(page_addr + L1_CACHE_BYTES); -#endif - - /* allocate a skb to store the frags */ - skb = napi_alloc_skb(&rx_ring->q_vector->napi, - IXGBE_RX_HDR_SIZE); - if (unlikely(!skb)) { - rx_ring->rx_stats.alloc_rx_buff_failed++; - return NULL; - } - - /* - * we will be copying header into skb->data in - * pskb_may_pull so it is in our interest to prefetch - * it now to avoid a possible cache miss - */ - prefetchw(skb->data); - - /* - * Delay unmapping of the first packet. It carries the - * header information, HW may still access the header - * after the writeback. Only unmap it when EOP is - * reached - */ - if (likely(ixgbe_test_staterr(rx_desc, IXGBE_RXD_STAT_EOP))) - goto dma_sync; - - IXGBE_CB(skb)->dma = rx_buffer->dma; + /* Delay unmapping of the first packet. It carries the header + * information, HW may still access the header after the writeback. + * Only unmap it when EOP is reached + */ + if (!ixgbe_test_staterr(rx_desc, IXGBE_RXD_STAT_EOP)) { + if (!*skb) + goto skip_sync; } else { - if (ixgbe_test_staterr(rx_desc, IXGBE_RXD_STAT_EOP)) - ixgbe_dma_sync_frag(rx_ring, skb); + if (*skb) + ixgbe_dma_sync_frag(rx_ring, *skb); + } -dma_sync: - /* we are reusing so sync this buffer for CPU use */ - dma_sync_single_range_for_cpu(rx_ring->dev, - rx_buffer->dma, - rx_buffer->page_offset, - size, - DMA_FROM_DEVICE); + /* we are reusing so sync this buffer for CPU use */ + dma_sync_single_range_for_cpu(rx_ring->dev, + rx_buffer->dma, + rx_buffer->page_offset, + size, + DMA_FROM_DEVICE); +skip_sync: + rx_buffer->pagecnt_bias--; - rx_buffer->skb = NULL; - } + return rx_buffer; +} - /* pull page into skb */ - if (ixgbe_add_rx_frag(rx_ring, rx_buffer, size, skb)) { +static void ixgbe_put_rx_buffer(struct ixgbe_ring *rx_ring, + struct ixgbe_rx_buffer *rx_buffer, + struct sk_buff *skb) +{ + if (ixgbe_can_reuse_rx_page(rx_buffer)) { /* hand second half of page back to the ring */ ixgbe_reuse_rx_page(rx_ring, rx_buffer); } else { @@ -2107,12 +2065,55 @@ dma_sync: DMA_FROM_DEVICE, IXGBE_RX_DMA_ATTR); } - __page_frag_cache_drain(page, + __page_frag_cache_drain(rx_buffer->page, rx_buffer->pagecnt_bias); } - /* clear contents of buffer_info */ + /* clear contents of rx_buffer */ rx_buffer->page = NULL; + rx_buffer->skb = NULL; +} + +static struct sk_buff *ixgbe_construct_skb(struct ixgbe_ring *rx_ring, + struct ixgbe_rx_buffer *rx_buffer, + union ixgbe_adv_rx_desc *rx_desc, + unsigned int size) +{ + void *va = page_address(rx_buffer->page) + rx_buffer->page_offset; +#if (PAGE_SIZE < 8192) + unsigned int truesize = ixgbe_rx_pg_size(rx_ring) / 2; +#else + unsigned int truesize = ALIGN(size, L1_CACHE_BYTES); +#endif + struct sk_buff *skb; + + /* prefetch first cache line of first page */ + prefetch(va); +#if L1_CACHE_BYTES < 128 + prefetch(va + L1_CACHE_BYTES); +#endif + + /* allocate a skb to store the frags */ + skb = napi_alloc_skb(&rx_ring->q_vector->napi, IXGBE_RX_HDR_SIZE); + if (unlikely(!skb)) + return NULL; + + if (size > IXGBE_RX_HDR_SIZE) { + if (!ixgbe_test_staterr(rx_desc, IXGBE_RXD_STAT_EOP)) + IXGBE_CB(skb)->dma = rx_buffer->dma; + + skb_add_rx_frag(skb, 0, rx_buffer->page, + rx_buffer->page_offset, + size, truesize); +#if (PAGE_SIZE < 8192) + rx_buffer->page_offset ^= truesize; +#else + rx_buffer->page_offset += truesize; +#endif + } else { + memcpy(__skb_put(skb, size), va, ALIGN(size, sizeof(long))); + rx_buffer->pagecnt_bias++; + } return skb; } @@ -2144,7 +2145,9 @@ static int ixgbe_clean_rx_irq(struct ixgbe_q_vector *q_vector, while (likely(total_rx_packets < budget)) { union ixgbe_adv_rx_desc *rx_desc; + struct ixgbe_rx_buffer *rx_buffer; struct sk_buff *skb; + unsigned int size; /* return some buffers to hardware, one at a time is too slow */ if (cleaned_count >= IXGBE_RX_BUFFER_WRITE) { @@ -2153,8 +2156,8 @@ static int ixgbe_clean_rx_irq(struct ixgbe_q_vector *q_vector, } rx_desc = IXGBE_RX_DESC(rx_ring, rx_ring->next_to_clean); - - if (!rx_desc->wb.upper.length) + size = le16_to_cpu(rx_desc->wb.upper.length); + if (!size) break; /* This memory barrier is needed to keep us from reading @@ -2163,13 +2166,23 @@ static int ixgbe_clean_rx_irq(struct ixgbe_q_vector *q_vector, */ dma_rmb(); + rx_buffer = ixgbe_get_rx_buffer(rx_ring, rx_desc, &skb, size); + /* retrieve a buffer from the ring */ - skb = ixgbe_fetch_rx_buffer(rx_ring, rx_desc); + if (skb) + ixgbe_add_rx_frag(rx_ring, rx_buffer, skb, size); + else + skb = ixgbe_construct_skb(rx_ring, rx_buffer, + rx_desc, size); /* exit if we failed to retrieve a buffer */ - if (!skb) + if (!skb) { + rx_ring->rx_stats.alloc_rx_buff_failed++; + rx_buffer->pagecnt_bias++; break; + } + ixgbe_put_rx_buffer(rx_ring, rx_buffer, skb); cleaned_count++; /* place incomplete frames back on ring for completion */