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authorEric Dumazet <edumazet@google.com>2013-07-29 10:24:04 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-08-11 18:35:26 -0700
commit1ec05e6b8c709aa7f250a4ddc9fd4e423bf4cfd1 (patch)
tree023709f16c1d5e2312dd4f0ed7208c1bbed67ade
parent6d60b440872edd1160f0f2eb97fe3e305019c99f (diff)
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atl1c: use custom skb allocator
[ Upstream commit 7b70176421993866e616f1cbc4d0dd4054f1bf78 ] We had reports ( https://bugzilla.kernel.org/show_bug.cgi?id=54021 ) that using high order pages for skb allocations is problematic for atl1c We do not know exactly what the problem is, but we suspect that crossing 4K pages is not well supported by this hardware. Use a custom allocator, using page allocator and 2K fragments for optimal stack behavior. We might make this allocator generic in future kernels. Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Luis Henriques <luis.henriques@canonical.com> Cc: Neil Horman <nhorman@tuxdriver.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--drivers/net/ethernet/atheros/atl1c/atl1c.h3
-rw-r--r--drivers/net/ethernet/atheros/atl1c/atl1c_main.c40
2 files changed, 42 insertions, 1 deletions
diff --git a/drivers/net/ethernet/atheros/atl1c/atl1c.h b/drivers/net/ethernet/atheros/atl1c/atl1c.h
index b2bf324631d..0f0556526ba 100644
--- a/drivers/net/ethernet/atheros/atl1c/atl1c.h
+++ b/drivers/net/ethernet/atheros/atl1c/atl1c.h
@@ -520,6 +520,9 @@ struct atl1c_adapter {
struct net_device *netdev;
struct pci_dev *pdev;
struct napi_struct napi;
+ struct page *rx_page;
+ unsigned int rx_page_offset;
+ unsigned int rx_frag_size;
struct atl1c_hw hw;
struct atl1c_hw_stats hw_stats;
struct mii_if_info mii; /* MII interface info */
diff --git a/drivers/net/ethernet/atheros/atl1c/atl1c_main.c b/drivers/net/ethernet/atheros/atl1c/atl1c_main.c
index 0ba900762b1..11cdf1d4304 100644
--- a/drivers/net/ethernet/atheros/atl1c/atl1c_main.c
+++ b/drivers/net/ethernet/atheros/atl1c/atl1c_main.c
@@ -481,10 +481,15 @@ static int atl1c_set_mac_addr(struct net_device *netdev, void *p)
static void atl1c_set_rxbufsize(struct atl1c_adapter *adapter,
struct net_device *dev)
{
+ unsigned int head_size;
int mtu = dev->mtu;
adapter->rx_buffer_len = mtu > AT_RX_BUF_SIZE ?
roundup(mtu + ETH_HLEN + ETH_FCS_LEN + VLAN_HLEN, 8) : AT_RX_BUF_SIZE;
+
+ head_size = SKB_DATA_ALIGN(adapter->rx_buffer_len + NET_SKB_PAD) +
+ SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
+ adapter->rx_frag_size = roundup_pow_of_two(head_size);
}
static netdev_features_t atl1c_fix_features(struct net_device *netdev,
@@ -952,6 +957,10 @@ static void atl1c_free_ring_resources(struct atl1c_adapter *adapter)
kfree(adapter->tpd_ring[0].buffer_info);
adapter->tpd_ring[0].buffer_info = NULL;
}
+ if (adapter->rx_page) {
+ put_page(adapter->rx_page);
+ adapter->rx_page = NULL;
+ }
}
/**
@@ -1639,6 +1648,35 @@ static inline void atl1c_rx_checksum(struct atl1c_adapter *adapter,
skb_checksum_none_assert(skb);
}
+static struct sk_buff *atl1c_alloc_skb(struct atl1c_adapter *adapter)
+{
+ struct sk_buff *skb;
+ struct page *page;
+
+ if (adapter->rx_frag_size > PAGE_SIZE)
+ return netdev_alloc_skb(adapter->netdev,
+ adapter->rx_buffer_len);
+
+ page = adapter->rx_page;
+ if (!page) {
+ adapter->rx_page = page = alloc_page(GFP_ATOMIC);
+ if (unlikely(!page))
+ return NULL;
+ adapter->rx_page_offset = 0;
+ }
+
+ skb = build_skb(page_address(page) + adapter->rx_page_offset,
+ adapter->rx_frag_size);
+ if (likely(skb)) {
+ adapter->rx_page_offset += adapter->rx_frag_size;
+ if (adapter->rx_page_offset >= PAGE_SIZE)
+ adapter->rx_page = NULL;
+ else
+ get_page(page);
+ }
+ return skb;
+}
+
static int atl1c_alloc_rx_buffer(struct atl1c_adapter *adapter)
{
struct atl1c_rfd_ring *rfd_ring = &adapter->rfd_ring;
@@ -1660,7 +1698,7 @@ static int atl1c_alloc_rx_buffer(struct atl1c_adapter *adapter)
while (next_info->flags & ATL1C_BUFFER_FREE) {
rfd_desc = ATL1C_RFD_DESC(rfd_ring, rfd_next_to_use);
- skb = netdev_alloc_skb(adapter->netdev, adapter->rx_buffer_len);
+ skb = atl1c_alloc_skb(adapter);
if (unlikely(!skb)) {
if (netif_msg_rx_err(adapter))
dev_warn(&pdev->dev, "alloc rx buffer failed\n");