From mboxrd@z Thu Jan 1 00:00:00 1970 From: Auke Kok Subject: Re: 2.6.1[78] page allocation failure. order:3, mode:0x20 Date: Sun, 24 Sep 2006 14:15:42 -0700 Message-ID: <4516F57E.7090603@intel.com> References: <20060922004253.2e2e2612.akpm@osdl.org> <4514190C.8010901@intel.com> <20060922215000.c1fde093.akpm@osdl.org> <20060922.222507.74751476.davem@davemloft.net> <20060922223348.1b24fda5.akpm@osdl.org> <20060924152651.GA2077@2ka.mipt.ru> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Evgeniy Polyakov , David Miller , Holger.Kiehl@dwd.de, linux-kernel@vger.kernel.org, linux-net@vger.kernel.org, netdev@vger.kernel.org, john.ronciak@intel.com Return-path: To: Andrew Morton In-Reply-To: <20060924152651.GA2077@2ka.mipt.ru> Sender: linux-net-owner@vger.kernel.org List-Id: netdev.vger.kernel.org Evgeniy Polyakov wrote: > On Fri, Sep 22, 2006 at 10:33:48PM -0700, Andrew Morton (akpm@osdl.org) wrote: >>> 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. > > This patch will not help - netdev_alloc_skb() adds additional > NET_SKB_PAD and then alloc_skb() adds sizeof(struct skb_shared_info). > And even if you acconut for them in adapter->rx_buf_len, chip still can > overwrite that area (in the thread mentioned in this e-mail thread > before I posted such patch and received a dump of sizes chip receives - > there were a lot of _different_ ones which were too close to the limit). I just did the math on it and it does not compute as I wanted too, we're basically flowing to the next larger buffersize 2 mtu bytes earlier, undoing any benefit completely. There is not much that can fix this issue since the hardware will always receive in 2-order buffers and dma that back in its entirity, so we must always claim size for NET_IP_ALIGN and NET_SKB_PAD after the 2-order bufsz. For the 9kb mtu case (16kb hw bufsz), we're stuck with 32kb slab allocations. bummer. Andrew, please drop this patch. Auke > >> 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 netdev" in >> the body of a message to majordomo@vger.kernel.org >> More majordomo info at http://vger.kernel.org/majordomo-info.html >