@@ -16,19 +16,23 @@ static void gve_rx_free_buffer(struct device *dev,
dma_addr_t dma = (dma_addr_t)(be64_to_cpu(data_slot->addr) &
GVE_DATA_SLOT_ADDR_PAGE_MASK);
+ page_ref_sub(page_info->page, page_info->pagecnt_bias - 1);
gve_free_page(dev, page_info->page, dma, DMA_FROM_DEVICE);
}
static void gve_rx_unfill_pages(struct gve_priv *priv, struct gve_rx_ring *rx)
{
- if (rx->data.raw_addressing) {
- u32 slots = rx->mask + 1;
- int i;
+ u32 slots = rx->mask + 1;
+ int i;
+ if (rx->data.raw_addressing) {
for (i = 0; i < slots; i++)
gve_rx_free_buffer(&priv->pdev->dev, &rx->data.page_info[i],
&rx->data.data_ring[i]);
} else {
+ for (i = 0; i < slots; i++)
+ page_ref_sub(rx->data.page_info[i].page,
+ rx->data.page_info[i].pagecnt_bias - 1);
gve_unassign_qpl(priv, rx->data.qpl->id);
rx->data.qpl = NULL;
}
@@ -69,6 +73,9 @@ static void gve_setup_rx_buffer(struct gve_rx_slot_page_info *page_info,
page_info->page_offset = 0;
page_info->page_address = page_address(page);
*slot_addr = cpu_to_be64(addr);
+ /* The page already has 1 ref */
+ page_ref_add(page, INT_MAX - 1);
+ page_info->pagecnt_bias = INT_MAX;
}
static int gve_rx_alloc_buffer(struct gve_priv *priv, struct device *dev,
@@ -293,17 +300,18 @@ static bool gve_rx_can_flip_buffers(struct net_device *netdev)
? netdev->mtu + GVE_RX_PAD + ETH_HLEN <= PAGE_SIZE / 2 : false;
}
-static int gve_rx_can_recycle_buffer(struct page *page)
+static int gve_rx_can_recycle_buffer(struct gve_rx_slot_page_info *page_info)
{
- int pagecount = page_count(page);
+ int pagecount = page_count(page_info->page);
/* This page is not being used by any SKBs - reuse */
- if (pagecount == 1)
+ if (pagecount == page_info->pagecnt_bias)
return 1;
/* This page is still being used by an SKB - we can't reuse */
- else if (pagecount >= 2)
+ else if (pagecount > page_info->pagecnt_bias)
return 0;
- WARN(pagecount < 1, "Pagecount should never be < 1");
+ WARN(pagecount < page_info->pagecnt_bias,
+ "Pagecount should never be less than the bias.");
return -1;
}
@@ -319,11 +327,11 @@ gve_rx_raw_addressing(struct device *dev, struct net_device *netdev,
if (!skb)
return NULL;
- /* Optimistically stop the kernel from freeing the page by increasing
- * the page bias. We will check the refcount in refill to determine if
- * we need to alloc a new page.
+ /* Optimistically stop the kernel from freeing the page.
+ * We will check again in refill to determine if we need to alloc a
+ * new page.
*/
- get_page(page_info->page);
+ gve_dec_pagecnt_bias(page_info);
return skb;
}
@@ -346,7 +354,7 @@ gve_rx_qpl(struct device *dev, struct net_device *netdev,
/* No point in recycling if we didn't get the skb */
if (skb) {
/* Make sure that the page isn't freed. */
- get_page(page_info->page);
+ gve_dec_pagecnt_bias(page_info);
gve_rx_flip_buff(page_info, &data_slot->qpl_offset);
}
} else {
@@ -370,8 +378,18 @@ static bool gve_rx(struct gve_rx_ring *rx, struct gve_rx_desc *rx_desc,
union gve_rx_data_slot *data_slot;
struct sk_buff *skb = NULL;
dma_addr_t page_bus;
+ void *va;
u16 len;
+ /* Prefetch two packet pages ahead, we will need it soon. */
+ page_info = &rx->data.page_info[(idx + 2) & rx->mask];
+ va = page_info->page_address + GVE_RX_PAD +
+ page_info->page_offset;
+
+ prefetch(page_info->page); /* Kernel page struct. */
+ prefetch(va); /* Packet header. */
+ prefetch(va + 64); /* Next cacheline too. */
+
/* drop this packet */
if (unlikely(rx_desc->flags_seq & GVE_RXF_ERR)) {
u64_stats_update_begin(&rx->statss);
@@ -402,7 +420,7 @@ static bool gve_rx(struct gve_rx_ring *rx, struct gve_rx_desc *rx_desc,
int recycle = 0;
if (can_flip) {
- recycle = gve_rx_can_recycle_buffer(page_info->page);
+ recycle = gve_rx_can_recycle_buffer(page_info);
if (recycle < 0) {
if (!rx->data.raw_addressing)
gve_schedule_reset(priv);
@@ -493,7 +511,7 @@ static bool gve_rx_refill_buffers(struct gve_priv *priv, struct gve_rx_ring *rx)
* owns half the page it is impossible to tell which half. Either
* the whole page is free or it needs to be replaced.
*/
- int recycle = gve_rx_can_recycle_buffer(page_info->page);
+ int recycle = gve_rx_can_recycle_buffer(page_info);
if (recycle < 0) {
if (!rx->data.raw_addressing)
@@ -540,6 +558,10 @@ int gve_clean_rx_done(struct gve_rx_ring *rx, int budget,
"[%d] seqno=%d rx->desc.seqno=%d\n",
rx->q_num, GVE_SEQNO(desc->flags_seq),
rx->desc.seqno);
+
+ /* prefetch two descriptors ahead */
+ prefetch(rx->desc.desc_ring + ((cnt + 2) & rx->mask));
+
dropped = !gve_rx(rx, desc, feat, idx);
if (!dropped) {
bytes += be16_to_cpu(desc->len) - GVE_RX_PAD;