[Intel-wired-lan] [PATCH 8/9] ixgbevf: break out Rx buffer page management
Emil Tantilov
emil.s.tantilov at intel.com
Wed Jan 31 00:51:49 UTC 2018
Based on commit e014272672b9 ("igb: Break out Rx buffer page management")
Consolidate Rx code paths to reduce duplication when we expand them in
the future.
Signed-off-by: Emil Tantilov <emil.s.tantilov at intel.com>
---
drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c | 227 +++++++++++----------
1 file changed, 114 insertions(+), 113 deletions(-)
diff --git a/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c b/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
index 754efb4..cd8c0a0 100644
--- a/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
+++ b/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
@@ -130,6 +130,9 @@ static void ixgbevf_service_event_complete(struct ixgbevf_adapter *adapter)
static void ixgbevf_queue_reset_subtask(struct ixgbevf_adapter *adapter);
static void ixgbevf_set_itr(struct ixgbevf_q_vector *q_vector);
static void ixgbevf_free_all_rx_resources(struct ixgbevf_adapter *adapter);
+static bool ixgbevf_can_reuse_rx_page(struct ixgbevf_rx_buffer *rx_buffer);
+static void ixgbevf_reuse_rx_page(struct ixgbevf_ring *rx_ring,
+ struct ixgbevf_rx_buffer *old_buff);
static void ixgbevf_remove_adapter(struct ixgbe_hw *hw)
{
@@ -527,6 +530,49 @@ static void ixgbevf_process_skb_fields(struct ixgbevf_ring *rx_ring,
skb->protocol = eth_type_trans(skb, rx_ring->netdev);
}
+static
+struct ixgbevf_rx_buffer *ixgbevf_get_rx_buffer(struct ixgbevf_ring *rx_ring,
+ const unsigned int size)
+{
+ struct ixgbevf_rx_buffer *rx_buffer;
+
+ rx_buffer = &rx_ring->rx_buffer_info[rx_ring->next_to_clean];
+ prefetchw(rx_buffer->page);
+
+ /* 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);
+
+ rx_buffer->pagecnt_bias--;
+
+ return rx_buffer;
+}
+
+static void ixgbevf_put_rx_buffer(struct ixgbevf_ring *rx_ring,
+ struct ixgbevf_rx_buffer *rx_buffer)
+{
+ if (ixgbevf_can_reuse_rx_page(rx_buffer)) {
+ /* hand second half of page back to the ring */
+ ixgbevf_reuse_rx_page(rx_ring, rx_buffer);
+ } else {
+ /* We are not reusing the buffer so unmap it and free
+ * any references we are holding to it
+ */
+ dma_unmap_page_attrs(rx_ring->dev, rx_buffer->dma,
+ ixgbevf_rx_pg_size(rx_ring),
+ DMA_FROM_DEVICE,
+ IXGBEVF_RX_DMA_ATTR);
+ __page_frag_cache_drain(rx_buffer->page,
+ rx_buffer->pagecnt_bias);
+ }
+
+ /* clear contents of rx_buffer */
+ rx_buffer->page = NULL;
+}
+
/**
* ixgbevf_is_non_eop - process handling of non-EOP buffers
* @rx_ring: Rx ring being processed
@@ -740,11 +786,10 @@ static inline bool ixgbevf_page_is_reserved(struct page *page)
return (page_to_nid(page) != numa_mem_id()) || page_is_pfmemalloc(page);
}
-static bool ixgbevf_can_reuse_rx_page(struct ixgbevf_rx_buffer *rx_buffer,
- struct page *page,
- const unsigned int truesize)
+static bool ixgbevf_can_reuse_rx_page(struct ixgbevf_rx_buffer *rx_buffer)
{
- 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(ixgbevf_page_is_reserved(page)))
@@ -752,16 +797,9 @@ static bool ixgbevf_can_reuse_rx_page(struct ixgbevf_rx_buffer *rx_buffer,
#if (PAGE_SIZE < 8192)
/* if we are only owner of page we can reuse it */
- if (unlikely(page_ref_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;
-
#define IXGBEVF_LAST_OFFSET \
(SKB_WITH_OVERHEAD(PAGE_SIZE) - IXGBEVF_RXBUFFER_2048)
@@ -774,7 +812,7 @@ static bool ixgbevf_can_reuse_rx_page(struct ixgbevf_rx_buffer *rx_buffer,
* 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;
}
@@ -786,25 +824,16 @@ static bool ixgbevf_can_reuse_rx_page(struct ixgbevf_rx_buffer *rx_buffer,
* ixgbevf_add_rx_frag - Add contents of Rx buffer to sk_buff
* @rx_ring: rx descriptor ring to transact packets on
* @rx_buffer: buffer containing page to add
- * @rx_desc: descriptor containing length of buffer written by hardware
* @skb: sk_buff to place the data into
+ * @size: size of buffer to be added
*
* This function will add the data contained in rx_buffer->page to the skb.
- * This is done either through a direct copy if the data in the buffer is
- * less than the skb header size, otherwise it will just attach the page as
- * a frag to the skb.
- *
- * The function will then update the page offset if necessary and return
- * true if the buffer can be reused by the adapter.
**/
-static bool ixgbevf_add_rx_frag(struct ixgbevf_ring *rx_ring,
+static void ixgbevf_add_rx_frag(struct ixgbevf_ring *rx_ring,
struct ixgbevf_rx_buffer *rx_buffer,
- u16 size,
- union ixgbe_adv_rx_desc *rx_desc,
- struct sk_buff *skb)
+ struct sk_buff *skb,
+ unsigned int size)
{
- struct page *page = rx_buffer->page;
- void *va = page_address(page) + rx_buffer->page_offset;
#if (PAGE_SIZE < 8192)
unsigned int truesize = ixgbevf_rx_pg_size(rx_ring) / 2;
#else
@@ -812,102 +841,64 @@ static bool ixgbevf_add_rx_frag(struct ixgbevf_ring *rx_ring,
SKB_DATA_ALIGN(IXGBEVF_SKB_PAD + size) :
SKB_DATA_ALIGN(size);
#endif
- unsigned int pull_len;
-
- if (unlikely(skb_is_nonlinear(skb)))
- goto add_tail_frag;
-
- if (likely(size <= IXGBEVF_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(!ixgbevf_page_is_reserved(page)))
- return true;
-
- /* this page cannot be reused so discard it */
- return false;
- }
-
- /* we need the header to contain the greater of either ETH_HLEN or
- * 60 bytes if the skb->len is less than 60 for skb_pad.
- */
- pull_len = eth_get_headlen(va, IXGBEVF_RX_HDR_SIZE);
-
- /* align pull length to size of long to optimize memcpy performance */
- memcpy(__skb_put(skb, pull_len), va, ALIGN(pull_len, sizeof(long)));
-
- /* update all of the pointers */
- va += pull_len;
- size -= pull_len;
-
-add_tail_frag:
- skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags, page,
- va - page_address(page), size, truesize);
-
- return ixgbevf_can_reuse_rx_page(rx_buffer, page, truesize);
+ skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags, 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
}
-static struct sk_buff *ixgbevf_fetch_rx_buffer(struct ixgbevf_ring *rx_ring,
- union ixgbe_adv_rx_desc *rx_desc,
- struct sk_buff *skb)
+static
+struct sk_buff *ixgbevf_construct_skb(struct ixgbevf_ring *rx_ring,
+ struct ixgbevf_rx_buffer *rx_buffer,
+ union ixgbe_adv_rx_desc *rx_desc,
+ unsigned int size)
{
- struct ixgbevf_rx_buffer *rx_buffer;
- struct page *page;
- u16 size = le16_to_cpu(rx_desc->wb.upper.length);
-
- rx_buffer = &rx_ring->rx_buffer_info[rx_ring->next_to_clean];
- page = rx_buffer->page;
- prefetchw(page);
-
- /* 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);
-
- if (likely(!skb)) {
- void *va = page_address(page) + rx_buffer->page_offset;
+ void *va = page_address(rx_buffer->page) + rx_buffer->page_offset;
+#if (PAGE_SIZE < 8192)
+ unsigned int truesize = ixgbevf_rx_pg_size(rx_ring) / 2;
+#else
+ unsigned int truesize = SKB_DATA_ALIGN(size);
+#endif
+ unsigned int headlen;
+ struct sk_buff *skb;
- /* prefetch first cache line of first page */
- prefetch(va);
+ /* prefetch first cache line of first page */
+ prefetch(va);
#if L1_CACHE_BYTES < 128
- prefetch(va + L1_CACHE_BYTES);
+ prefetch(va + L1_CACHE_BYTES);
#endif
- /* allocate a skb to store the frags */
- skb = netdev_alloc_skb_ip_align(rx_ring->netdev,
- IXGBEVF_RX_HDR_SIZE);
- if (unlikely(!skb)) {
- rx_ring->rx_stats.alloc_rx_buff_failed++;
- return NULL;
- }
+ /* allocate a skb to store the frags */
+ skb = napi_alloc_skb(&rx_ring->q_vector->napi, IXGBEVF_RX_HDR_SIZE);
+ if (unlikely(!skb))
+ 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);
- }
+ /* Determine available headroom for copy */
+ headlen = size;
+ if (headlen > IXGBEVF_RX_HDR_SIZE)
+ headlen = eth_get_headlen(va, IXGBEVF_RX_HDR_SIZE);
- /* pull page into skb */
- if (ixgbevf_add_rx_frag(rx_ring, rx_buffer, size, rx_desc, skb)) {
- /* hand second half of page back to the ring */
- ixgbevf_reuse_rx_page(rx_ring, rx_buffer);
+ /* align pull length to size of long to optimize memcpy performance */
+ memcpy(__skb_put(skb, headlen), va, ALIGN(headlen, sizeof(long)));
+
+ /* update all of the pointers */
+ size -= headlen;
+ if (size) {
+ skb_add_rx_frag(skb, 0, rx_buffer->page,
+ (va + headlen) - page_address(rx_buffer->page),
+ size, truesize);
+#if (PAGE_SIZE < 8192)
+ rx_buffer->page_offset ^= truesize;
+#else
+ rx_buffer->page_offset += truesize;
+#endif
} else {
- /* We are not reusing the buffer so unmap it and free
- * any references we are holding to it
- */
- dma_unmap_page_attrs(rx_ring->dev, rx_buffer->dma,
- ixgbevf_rx_pg_size(rx_ring),
- DMA_FROM_DEVICE, IXGBEVF_RX_DMA_ATTR);
- __page_frag_cache_drain(page, rx_buffer->pagecnt_bias);
+ rx_buffer->pagecnt_bias++;
}
- /* clear contents of buffer_info */
- rx_buffer->dma = 0;
- rx_buffer->page = NULL;
-
return skb;
}
@@ -929,6 +920,8 @@ static int ixgbevf_clean_rx_irq(struct ixgbevf_q_vector *q_vector,
while (likely(total_rx_packets < budget)) {
union ixgbe_adv_rx_desc *rx_desc;
+ struct ixgbevf_rx_buffer *rx_buffer;
+ unsigned int size;
/* return some buffers to hardware, one at a time is too slow */
if (cleaned_count >= IXGBEVF_RX_BUFFER_WRITE) {
@@ -937,8 +930,8 @@ static int ixgbevf_clean_rx_irq(struct ixgbevf_q_vector *q_vector,
}
rx_desc = IXGBEVF_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
@@ -947,15 +940,23 @@ static int ixgbevf_clean_rx_irq(struct ixgbevf_q_vector *q_vector,
*/
rmb();
+ rx_buffer = ixgbevf_get_rx_buffer(rx_ring, size);
+
/* retrieve a buffer from the ring */
- skb = ixgbevf_fetch_rx_buffer(rx_ring, rx_desc, skb);
+ if (skb)
+ ixgbevf_add_rx_frag(rx_ring, rx_buffer, skb, size);
+ else
+ skb = ixgbevf_construct_skb(rx_ring, rx_buffer,
+ rx_desc, size);
/* exit if we failed to retrieve a buffer */
if (!skb) {
rx_ring->rx_stats.alloc_rx_buff_failed++;
+ rx_buffer->pagecnt_bias++;
break;
}
+ ixgbevf_put_rx_buffer(rx_ring, rx_buffer);
cleaned_count++;
/* fetch next buffer in frame if non-eop */
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