Commit 7b701764 authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller

atl1c: Fix misuse of netdev_alloc_skb in refilling rx ring

On Mon, 2013-07-29 at 08:30 -0700, Eric Dumazet wrote:
> On Mon, 2013-07-29 at 13:09 +0100, Luis Henriques wrote:
>
> >
> > I confirm that I can't reproduce the issue using this patch.
> >
>
> Thanks, I'll send a polished patch, as this one had an error if
> build_skb() returns NULL (in case sk_buff allocation fails)

Please try the following patch : It should use 2K frags instead of 4K
for normal 1500 mtu

Thanks !

[PATCH] atl1c: use custom skb allocator

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: default avatarEric Dumazet <edumazet@google.com>
Cc: Luis Henriques <luis.henriques@canonical.com>
Cc: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent e1ee3673
...@@ -520,6 +520,9 @@ struct atl1c_adapter { ...@@ -520,6 +520,9 @@ struct atl1c_adapter {
struct net_device *netdev; struct net_device *netdev;
struct pci_dev *pdev; struct pci_dev *pdev;
struct napi_struct napi; 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 hw;
struct atl1c_hw_stats hw_stats; struct atl1c_hw_stats hw_stats;
struct mii_if_info mii; /* MII interface info */ struct mii_if_info mii; /* MII interface info */
......
...@@ -481,10 +481,15 @@ static int atl1c_set_mac_addr(struct net_device *netdev, void *p) ...@@ -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, static void atl1c_set_rxbufsize(struct atl1c_adapter *adapter,
struct net_device *dev) struct net_device *dev)
{ {
unsigned int head_size;
int mtu = dev->mtu; int mtu = dev->mtu;
adapter->rx_buffer_len = mtu > AT_RX_BUF_SIZE ? adapter->rx_buffer_len = mtu > AT_RX_BUF_SIZE ?
roundup(mtu + ETH_HLEN + ETH_FCS_LEN + VLAN_HLEN, 8) : 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, 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) ...@@ -952,6 +957,10 @@ static void atl1c_free_ring_resources(struct atl1c_adapter *adapter)
kfree(adapter->tpd_ring[0].buffer_info); kfree(adapter->tpd_ring[0].buffer_info);
adapter->tpd_ring[0].buffer_info = NULL; 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, ...@@ -1639,6 +1648,35 @@ static inline void atl1c_rx_checksum(struct atl1c_adapter *adapter,
skb_checksum_none_assert(skb); 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) static int atl1c_alloc_rx_buffer(struct atl1c_adapter *adapter)
{ {
struct atl1c_rfd_ring *rfd_ring = &adapter->rfd_ring; struct atl1c_rfd_ring *rfd_ring = &adapter->rfd_ring;
...@@ -1660,7 +1698,7 @@ static int atl1c_alloc_rx_buffer(struct atl1c_adapter *adapter) ...@@ -1660,7 +1698,7 @@ static int atl1c_alloc_rx_buffer(struct atl1c_adapter *adapter)
while (next_info->flags & ATL1C_BUFFER_FREE) { while (next_info->flags & ATL1C_BUFFER_FREE) {
rfd_desc = ATL1C_RFD_DESC(rfd_ring, rfd_next_to_use); 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 (unlikely(!skb)) {
if (netif_msg_rx_err(adapter)) if (netif_msg_rx_err(adapter))
dev_warn(&pdev->dev, "alloc rx buffer failed\n"); dev_warn(&pdev->dev, "alloc rx buffer failed\n");
......
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