On Fri, 22 Sep 2006 22:25:07 -0700 (PDT) David Miller <davem@xxxxxxxxxxxxx> wrote: > From: Andrew Morton <akpm@xxxxxxxx> > Date: Fri, 22 Sep 2006 21:50:00 -0700 > > > On Fri, 22 Sep 2006 10:10:36 -0700 > > Auke Kok <auke-jan.h.kok@xxxxxxxxx> wrote: > > > > > e1000: account for NET_IP_ALIGN when calculating bufsiz > > > > > > Account for NET_IP_ALIGN when requesting buffer sizes from netdev_alloc_skb to > > > reduce slab allocation by half. > > > > Could we please do whatever is needed to get this blessed and merged? This > > is such a common problem on such a common driver that I would suggest that > > we want this in 2.6.18.x as well. At least, I'd expect distributors to > > ship this fix (they're nuts if they don't) and so it makes sense to deliver > > it from kernel.org. > > The NET_IP_ALIGN existed not just for fun :) There are ramifications > for removing it. It's still there, isn't it? For the 9k MTU case, for example, we end up allocating 16384 byte skbs instead of 32786 kbytes ones. diff -puN drivers/net/e1000/e1000_main.c~e1000-account-for-net_ip_align-when-calculating-bufsiz drivers/net/e1000/e1000_main.c --- a/drivers/net/e1000/e1000_main.c~e1000-account-for-net_ip_align-when-calculating-bufsiz +++ a/drivers/net/e1000/e1000_main.c @@ -1101,7 +1101,7 @@ e1000_sw_init(struct e1000_adapter *adap pci_read_config_word(pdev, PCI_COMMAND, &hw->pci_cmd_word); - adapter->rx_buffer_len = MAXIMUM_ETHERNET_VLAN_SIZE; + adapter->rx_buffer_len = MAXIMUM_ETHERNET_VLAN_SIZE + NET_IP_ALIGN; adapter->rx_ps_bsize0 = E1000_RXBUFFER_128; hw->max_frame_size = netdev->mtu + ENET_HEADER_SIZE + ETHERNET_FCS_SIZE; @@ -3163,26 +3163,27 @@ e1000_change_mtu(struct net_device *netd * larger slab size * i.e. RXBUFFER_2048 --> size-4096 slab */ - if (max_frame <= E1000_RXBUFFER_256) + if (max_frame + NET_IP_ALIGN <= E1000_RXBUFFER_256) adapter->rx_buffer_len = E1000_RXBUFFER_256; - else if (max_frame <= E1000_RXBUFFER_512) + else if (max_frame + NET_IP_ALIGN <= E1000_RXBUFFER_512) adapter->rx_buffer_len = E1000_RXBUFFER_512; - else if (max_frame <= E1000_RXBUFFER_1024) + else if (max_frame + NET_IP_ALIGN <= E1000_RXBUFFER_1024) adapter->rx_buffer_len = E1000_RXBUFFER_1024; - else if (max_frame <= E1000_RXBUFFER_2048) + else if (max_frame + NET_IP_ALIGN <= E1000_RXBUFFER_2048) adapter->rx_buffer_len = E1000_RXBUFFER_2048; - else if (max_frame <= E1000_RXBUFFER_4096) + else if (max_frame + NET_IP_ALIGN <= E1000_RXBUFFER_4096) adapter->rx_buffer_len = E1000_RXBUFFER_4096; - else if (max_frame <= E1000_RXBUFFER_8192) + else if (max_frame + NET_IP_ALIGN <= E1000_RXBUFFER_8192) adapter->rx_buffer_len = E1000_RXBUFFER_8192; - else if (max_frame <= E1000_RXBUFFER_16384) + else adapter->rx_buffer_len = E1000_RXBUFFER_16384; /* adjust allocation if LPE protects us, and we aren't using SBP */ if (!adapter->hw.tbi_compatibility_on && ((max_frame == MAXIMUM_ETHERNET_FRAME_SIZE) || (max_frame == MAXIMUM_ETHERNET_VLAN_SIZE))) - adapter->rx_buffer_len = MAXIMUM_ETHERNET_VLAN_SIZE; + adapter->rx_buffer_len = MAXIMUM_ETHERNET_VLAN_SIZE + + NET_IP_ALIGN; netdev->mtu = new_mtu; @@ -4002,7 +4003,8 @@ e1000_alloc_rx_buffers(struct e1000_adap struct e1000_buffer *buffer_info; struct sk_buff *skb; unsigned int i; - unsigned int bufsz = adapter->rx_buffer_len + NET_IP_ALIGN; + /* we have already accounted for NET_IP_ALIGN */ + unsigned int bufsz = adapter->rx_buffer_len; i = rx_ring->next_to_use; buffer_info = &rx_ring->buffer_info[i]; _ - To unsubscribe from this list: send the line "unsubscribe linux-net" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
