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Date: Fri, 19 Oct 2012 04:45:10 -0700
From: Jeff Kirsher <jeffrey.t.kirsher@...el.com>
To: davem@...emloft.net
Cc: Alexander Duyck <alexander.h.duyck@...el.com>,
netdev@...r.kernel.org, gospo@...hat.com, sassmann@...hat.com,
Jeff Kirsher <jeffrey.t.kirsher@...el.com>
Subject: [net-next 10/14] igb: Move rx_buffer related code in Rx cleanup path into separate function
From: Alexander Duyck <alexander.h.duyck@...el.com>
In order to try and isolate things a bit further I am moving the code
related to retrieving data from the rx_buffer_info structure into a
separate function.
Signed-off-by: Alexander Duyck <alexander.h.duyck@...el.com>
Tested-by: Aaron Brown <aaron.f.brown@...el.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@...el.com>
---
drivers/net/ethernet/intel/igb/igb_main.c | 206 +++++++++++++++++-------------
1 file changed, 120 insertions(+), 86 deletions(-)
diff --git a/drivers/net/ethernet/intel/igb/igb_main.c b/drivers/net/ethernet/intel/igb/igb_main.c
index 18ad18f..fa7ddec 100644
--- a/drivers/net/ethernet/intel/igb/igb_main.c
+++ b/drivers/net/ethernet/intel/igb/igb_main.c
@@ -5928,6 +5928,74 @@ static bool igb_add_rx_frag(struct igb_ring *rx_ring,
return true;
}
+static struct sk_buff *igb_fetch_rx_buffer(struct igb_ring *rx_ring,
+ union e1000_adv_rx_desc *rx_desc,
+ struct sk_buff *skb)
+{
+ struct igb_rx_buffer *rx_buffer;
+ struct page *page;
+
+ rx_buffer = &rx_ring->rx_buffer_info[rx_ring->next_to_clean];
+
+ /*
+ * This memory barrier is needed to keep us from reading
+ * any other fields out of the rx_desc until we know the
+ * RXD_STAT_DD bit is set
+ */
+ rmb();
+
+ page = rx_buffer->page;
+ prefetchw(page);
+
+ if (likely(!skb)) {
+ void *page_addr = page_address(page) +
+ rx_buffer->page_offset;
+
+ /* 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 = netdev_alloc_skb_ip_align(rx_ring->netdev,
+ IGB_RX_HDR_LEN);
+ if (unlikely(!skb)) {
+ rx_ring->rx_stats.alloc_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);
+ }
+
+ /* 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,
+ PAGE_SIZE / 2,
+ DMA_FROM_DEVICE);
+
+ /* pull page into skb */
+ if (igb_add_rx_frag(rx_ring, rx_buffer, rx_desc, skb)) {
+ /* hand second half of page back to the ring */
+ igb_reuse_rx_page(rx_ring, rx_buffer);
+ } else {
+ /* we are not reusing the buffer so unmap it */
+ dma_unmap_page(rx_ring->dev, rx_buffer->dma,
+ PAGE_SIZE, DMA_FROM_DEVICE);
+ }
+
+ /* clear contents of rx_buffer */
+ rx_buffer->page = NULL;
+
+ return skb;
+}
+
static inline void igb_rx_checksum(struct igb_ring *ring,
union e1000_adv_rx_desc *rx_desc,
struct sk_buff *skb)
@@ -5978,6 +6046,34 @@ static inline void igb_rx_hash(struct igb_ring *ring,
}
/**
+ * igb_is_non_eop - process handling of non-EOP buffers
+ * @rx_ring: Rx ring being processed
+ * @rx_desc: Rx descriptor for current buffer
+ * @skb: current socket buffer containing buffer in progress
+ *
+ * This function updates next to clean. If the buffer is an EOP buffer
+ * this function exits returning false, otherwise it will place the
+ * sk_buff in the next buffer to be chained and return true indicating
+ * that this is in fact a non-EOP buffer.
+ **/
+static bool igb_is_non_eop(struct igb_ring *rx_ring,
+ union e1000_adv_rx_desc *rx_desc)
+{
+ u32 ntc = rx_ring->next_to_clean + 1;
+
+ /* fetch, update, and store next to clean */
+ ntc = (ntc < rx_ring->count) ? ntc : 0;
+ rx_ring->next_to_clean = ntc;
+
+ prefetch(IGB_RX_DESC(rx_ring, ntc));
+
+ if (likely(igb_test_staterr(rx_desc, E1000_RXD_STAT_EOP)))
+ return false;
+
+ return true;
+}
+
+/**
* igb_get_headlen - determine size of header for LRO/GRO
* @data: pointer to the start of the headers
* @max_len: total length of section to find headers in
@@ -6227,87 +6323,39 @@ static void igb_process_skb_fields(struct igb_ring *rx_ring,
skb->protocol = eth_type_trans(skb, rx_ring->netdev);
}
-static bool igb_clean_rx_irq(struct igb_q_vector *q_vector, int budget)
+static bool igb_clean_rx_irq(struct igb_q_vector *q_vector, const int budget)
{
struct igb_ring *rx_ring = q_vector->rx.ring;
- union e1000_adv_rx_desc *rx_desc;
struct sk_buff *skb = rx_ring->skb;
unsigned int total_bytes = 0, total_packets = 0;
u16 cleaned_count = igb_desc_unused(rx_ring);
- u16 i = rx_ring->next_to_clean;
-
- rx_desc = IGB_RX_DESC(rx_ring, i);
-
- while (igb_test_staterr(rx_desc, E1000_RXD_STAT_DD)) {
- struct igb_rx_buffer *buffer_info = &rx_ring->rx_buffer_info[i];
- struct page *page;
- union e1000_adv_rx_desc *next_rxd;
-
- i++;
- if (i == rx_ring->count)
- i = 0;
-
- next_rxd = IGB_RX_DESC(rx_ring, i);
- prefetch(next_rxd);
- /*
- * This memory barrier is needed to keep us from reading
- * any other fields out of the rx_desc until we know the
- * RXD_STAT_DD bit is set
- */
- rmb();
-
- page = buffer_info->page;
- prefetchw(page);
+ do {
+ union e1000_adv_rx_desc *rx_desc;
- if (likely(!skb)) {
- void *page_addr = page_address(page) +
- buffer_info->page_offset;
+ /* return some buffers to hardware, one at a time is too slow */
+ if (cleaned_count >= IGB_RX_BUFFER_WRITE) {
+ igb_alloc_rx_buffers(rx_ring, cleaned_count);
+ cleaned_count = 0;
+ }
- /* prefetch first cache line of first page */
- prefetch(page_addr);
-#if L1_CACHE_BYTES < 128
- prefetch(page_addr + L1_CACHE_BYTES);
-#endif
+ rx_desc = IGB_RX_DESC(rx_ring, rx_ring->next_to_clean);
- /* allocate a skb to store the frags */
- skb = netdev_alloc_skb_ip_align(rx_ring->netdev,
- IGB_RX_HDR_LEN);
- if (unlikely(!skb)) {
- rx_ring->rx_stats.alloc_failed++;
- break;
- }
+ if (!igb_test_staterr(rx_desc, E1000_RXD_STAT_DD))
+ break;
- /*
- * 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);
- }
+ /* retrieve a buffer from the ring */
+ skb = igb_fetch_rx_buffer(rx_ring, rx_desc, skb);
- /* we are reusing so sync this buffer for CPU use */
- dma_sync_single_range_for_cpu(rx_ring->dev,
- buffer_info->dma,
- buffer_info->page_offset,
- PAGE_SIZE / 2,
- DMA_FROM_DEVICE);
-
- /* pull page into skb */
- if (igb_add_rx_frag(rx_ring, buffer_info, rx_desc, skb)) {
- /* hand second half of page back to the ring */
- igb_reuse_rx_page(rx_ring, buffer_info);
- } else {
- /* we are not reusing the buffer so unmap it */
- dma_unmap_page(rx_ring->dev, buffer_info->dma,
- PAGE_SIZE, DMA_FROM_DEVICE);
- }
+ /* exit if we failed to retrieve a buffer */
+ if (!skb)
+ break;
- /* clear contents of buffer_info */
- buffer_info->page = NULL;
+ cleaned_count++;
- if (!igb_test_staterr(rx_desc, E1000_RXD_STAT_EOP))
- goto next_desc;
+ /* fetch next buffer in frame if non-eop */
+ if (igb_is_non_eop(rx_ring, rx_desc))
+ continue;
/* verify the packet layout is correct */
if (igb_cleanup_headers(rx_ring, rx_desc, skb)) {
@@ -6317,7 +6365,6 @@ static bool igb_clean_rx_irq(struct igb_q_vector *q_vector, int budget)
/* probably a little skewed due to removing CRC */
total_bytes += skb->len;
- total_packets++;
/* populate checksum, timestamp, VLAN, and protocol */
igb_process_skb_fields(rx_ring, rx_desc, skb);
@@ -6327,26 +6374,13 @@ static bool igb_clean_rx_irq(struct igb_q_vector *q_vector, int budget)
/* reset skb pointer */
skb = NULL;
- budget--;
-next_desc:
- if (!budget)
- break;
-
- cleaned_count++;
- /* return some buffers to hardware, one at a time is too slow */
- if (cleaned_count >= IGB_RX_BUFFER_WRITE) {
- igb_alloc_rx_buffers(rx_ring, cleaned_count);
- cleaned_count = 0;
- }
-
- /* use prefetched values */
- rx_desc = next_rxd;
- }
+ /* update budget accounting */
+ total_packets++;
+ } while (likely(total_packets < budget));
/* place incomplete frames back on ring for completion */
rx_ring->skb = skb;
- rx_ring->next_to_clean = i;
u64_stats_update_begin(&rx_ring->rx_syncp);
rx_ring->rx_stats.packets += total_packets;
rx_ring->rx_stats.bytes += total_bytes;
@@ -6357,7 +6391,7 @@ next_desc:
if (cleaned_count)
igb_alloc_rx_buffers(rx_ring, cleaned_count);
- return !!budget;
+ return (total_packets < budget);
}
static bool igb_alloc_mapped_page(struct igb_ring *rx_ring,
--
1.7.11.7
--
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