[NET-NEXT PATCH 15/18] igb: add page recycling support

Jeff Kirsher
2008-06-27T18:06:52Z

From: Alexander Duyck <alexander.h.duyck@intel.com>

This patch adds support for page recycling by splitting the page into two
usable portions and tracking the reference count.

Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
---

drivers/net/igb/igb.h | 4 -
drivers/net/igb/igb_main.c | 138 ++++++++++++++++++++------------------------
2 files changed, 63 insertions(+), 79 deletions(-)

diff --git a/drivers/net/igb/igb.h b/drivers/net/igb/igb.h
index 97f03da..da7bbaf 100644
--- a/drivers/net/igb/igb.h
+++ b/drivers/net/igb/igb.h
@@ -125,6 +125,7 @@ struct igb_buffer {
struct {
struct page *page;
u64 page_dma;
+ unsigned int page_offset;
};
};
};
@@ -163,9 +164,6 @@ struct igb_ring {
};
/* RX */
struct {
- /* arrays of page information for packet split */
- struct sk_buff *pending_skb;
- int pending_skb_page;
int no_itr_adjust;
struct igb_queue_stats rx_stats;
struct napi_struct napi;
diff --git a/drivers/net/igb/igb_main.c b/drivers/net/igb/igb_main.c
index 43f288a..2b5dbc7 100644
--- a/drivers/net/igb/igb_main.c
+++ b/drivers/net/igb/igb_main.c
@@ -1698,7 +1698,6 @@ int igb_setup_rx_resources(struct igb_adapter *adapter,

rx_ring->next_to_clean = 0;
rx_ring->next_to_use = 0;
- rx_ring->pending_skb = NULL;

rx_ring->adapter = adapter;

@@ -1790,15 +1789,6 @@ static void igb_setup_rctl(struct igb_adapter *adapter)
rctl |= E1000_RCTL_SZ_2048;
rctl &= ~E1000_RCTL_BSEX;
break;
- case IGB_RXBUFFER_4096:
- rctl |= E1000_RCTL_SZ_4096;
- break;
- case IGB_RXBUFFER_8192:
- rctl |= E1000_RCTL_SZ_8192;
- break;
- case IGB_RXBUFFER_16384:
- rctl |= E1000_RCTL_SZ_16384;
- break;
}
} else {
rctl &= ~E1000_RCTL_BSEX;
@@ -1816,10 +1806,8 @@ static void igb_setup_rctl(struct igb_adapter *adapter)
* so only enable packet split for jumbo frames */
if (rctl & E1000_RCTL_LPE) {
adapter->rx_ps_hdr_size = IGB_RXBUFFER_128;
- srrctl = adapter->rx_ps_hdr_size <<
+ srrctl |= adapter->rx_ps_hdr_size <<
E1000_SRRCTL_BSIZEHDRSIZE_SHIFT;
- /* buffer size is ALWAYS one page */
- srrctl |= PAGE_SIZE >> E1000_SRRCTL_BSIZEPKT_SHIFT;
srrctl |= E1000_SRRCTL_DESCTYPE_HDR_SPLIT_ALWAYS;
} else {
adapter->rx_ps_hdr_size = 0;
@@ -2124,20 +2112,17 @@ static void igb_clean_rx_ring(struct igb_ring *rx_ring)
buffer_info->skb = NULL;
}
if (buffer_info->page) {
- pci_unmap_page(pdev, buffer_info->page_dma,
- PAGE_SIZE, PCI_DMA_FROMDEVICE);
+ if (buffer_info->page_dma)
+ pci_unmap_page(pdev, buffer_info->page_dma,
+ PAGE_SIZE / 2,
+ PCI_DMA_FROMDEVICE);
put_page(buffer_info->page);
buffer_info->page = NULL;
buffer_info->page_dma = 0;
+ buffer_info->page_offset = 0;
}
}

- /* there also may be some cached data from a chained receive */
- if (rx_ring->pending_skb) {
- dev_kfree_skb(rx_ring->pending_skb);
- rx_ring->pending_skb = NULL;
- }
-
size = sizeof(struct igb_buffer) * rx_ring->count;
memset(rx_ring->buffer_info, 0, size);

@@ -3064,7 +3049,11 @@ static int igb_change_mtu(struct net_device *netdev, int new_mtu)
else if (max_frame <= IGB_RXBUFFER_2048)
adapter->rx_buffer_len = IGB_RXBUFFER_2048;
else
- adapter->rx_buffer_len = IGB_RXBUFFER_4096;
+#if (PAGE_SIZE / 2) > IGB_RXBUFFER_16384
+ adapter->rx_buffer_len = IGB_RXBUFFER_16384;
+#else
+ adapter->rx_buffer_len = PAGE_SIZE / 2;
+#endif
/* adjust allocation if LPE protects us, and we aren't using SBP */
if ((max_frame == ETH_FRAME_LEN + ETH_FCS_LEN) ||
(max_frame == MAXIMUM_ETHERNET_VLAN_SIZE))
@@ -3770,7 +3759,7 @@ static bool igb_clean_rx_irq_adv(struct igb_ring *rx_ring,
union e1000_adv_rx_desc *rx_desc , *next_rxd;
struct igb_buffer *buffer_info , *next_buffer;
struct sk_buff *skb;
- unsigned int i, j;
+ unsigned int i;
u32 length, hlen, staterr;
bool cleaned = false;
int cleaned_count = 0;
@@ -3800,61 +3789,46 @@ static bool igb_clean_rx_irq_adv(struct igb_ring *rx_ring,
cleaned = true;
cleaned_count++;

- if (rx_ring->pending_skb != NULL) {
- skb = rx_ring->pending_skb;
- rx_ring->pending_skb = NULL;
- j = rx_ring->pending_skb_page;
- } else {
- skb = buffer_info->skb;
- prefetch(skb->data - NET_IP_ALIGN);
- buffer_info->skb = NULL;
- if (hlen) {
- pci_unmap_single(pdev, buffer_info->dma,
- adapter->rx_ps_hdr_size +
- NET_IP_ALIGN,
- PCI_DMA_FROMDEVICE);
- skb_put(skb, hlen);
- } else {
- pci_unmap_single(pdev, buffer_info->dma,
- adapter->rx_buffer_len +
- NET_IP_ALIGN,
- PCI_DMA_FROMDEVICE);
- skb_put(skb, length);
- goto send_up;
- }
- j = 0;
+ skb = buffer_info->skb;
+ prefetch(skb->data - NET_IP_ALIGN);
+ buffer_info->skb = NULL;
+ if (!adapter->rx_ps_hdr_size) {
+ pci_unmap_single(pdev, buffer_info->dma,
+ adapter->rx_buffer_len +
+ NET_IP_ALIGN,
+ PCI_DMA_FROMDEVICE);
+ skb_put(skb, length);
+ goto send_up;
+ }
+
+ if (!skb_shinfo(skb)->nr_frags) {
+ pci_unmap_single(pdev, buffer_info->dma,
+ adapter->rx_ps_hdr_size +
+ NET_IP_ALIGN,
+ PCI_DMA_FROMDEVICE);
+ skb_put(skb, hlen);
}

- while (length) {
+ if (length) {
pci_unmap_page(pdev, buffer_info->page_dma,
- PAGE_SIZE, PCI_DMA_FROMDEVICE);
+ PAGE_SIZE / 2, PCI_DMA_FROMDEVICE);
buffer_info->page_dma = 0;
- skb_fill_page_desc(skb, j, buffer_info->page,
- 0, length);
- buffer_info->page = NULL;
+
+ skb_fill_page_desc(skb, skb_shinfo(skb)->nr_frags++,
+ buffer_info->page,
+ buffer_info->page_offset,
+ length);
+
+ if ((adapter->rx_buffer_len > (PAGE_SIZE / 2)) ||
+ (page_count(buffer_info->page) != 1))
+ buffer_info->page = NULL;
+ else
+ get_page(buffer_info->page);

skb->len += length;
skb->data_len += length;
- skb->truesize += length;
- rx_desc->wb.upper.status_error = 0;
- if (staterr & E1000_RXD_STAT_EOP)
- break;
-
- j++;
- cleaned_count++;
- i++;
- if (i == rx_ring->count)
- i = 0;

- buffer_info = &rx_ring->buffer_info[i];
- rx_desc = E1000_RX_DESC_ADV(*rx_ring, i);
- staterr = le32_to_cpu(rx_desc->wb.upper.status_error);
- length = le16_to_cpu(rx_desc->wb.upper.length);
- if (!(staterr & E1000_RXD_STAT_DD)) {
- rx_ring->pending_skb = skb;
- rx_ring->pending_skb_page = j;
- goto out;
- }
+ skb->truesize += length;
}
send_up:
i++;
@@ -3864,6 +3838,12 @@ send_up:
prefetch(next_rxd);
next_buffer = &rx_ring->buffer_info[i];

+ if (!(staterr & E1000_RXD_STAT_EOP)) {
+ buffer_info->skb = xchg(&next_buffer->skb, skb);
+ buffer_info->dma = xchg(&next_buffer->dma, 0);
+ goto next_desc;
+ }
+
if (staterr & E1000_RXDEXT_ERR_FRAME_ERR_MASK) {
dev_kfree_skb_irq(skb);
goto next_desc;
@@ -3896,7 +3876,7 @@ next_desc:

staterr = le32_to_cpu(rx_desc->wb.upper.status_error);
}
-out:
+
rx_ring->next_to_clean = i;
cleaned_count = IGB_DESC_UNUSED(rx_ring);

@@ -3934,16 +3914,22 @@ static void igb_alloc_rx_buffers_adv(struct igb_ring *rx_ring,
while (cleaned_count--) {
rx_desc = E1000_RX_DESC_ADV(*rx_ring, i);

- if (adapter->rx_ps_hdr_size && !buffer_info->page) {
- buffer_info->page = alloc_page(GFP_ATOMIC);
+ if (adapter->rx_ps_hdr_size && !buffer_info->page_dma) {
if (!buffer_info->page) {
- adapter->alloc_rx_buff_failed++;
- goto no_buffers;
+ buffer_info->page = alloc_page(GFP_ATOMIC);
+ if (!buffer_info->page) {
+ adapter->alloc_rx_buff_failed++;
+ goto no_buffers;
+ }
+ buffer_info->page_offset = 0;
+ } else {
+ buffer_info->page_offset ^= PAGE_SIZE / 2;
}
buffer_info->page_dma =
pci_map_page(pdev,
buffer_info->page,
- 0, PAGE_SIZE,
+ buffer_info->page_offset,
+ PAGE_SIZE / 2,
PCI_DMA_FROMDEVICE);
}