From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff Kirsher Subject: [net-next-2.6 PATCH 10/13] igb: use buffer_info->dma instead of shinfo->nr_frags to determine unmap Date: Thu, 23 Jul 2009 21:10:06 -0700 Message-ID: <20090724041005.30709.61385.stgit@localhost.localdomain> References: <20090724040700.30709.31473.stgit@localhost.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, gospo@redhat.com, Alexander Duyck , Jeff Kirsher To: davem@davemloft.net Return-path: Received: from qmta11.emeryville.ca.mail.comcast.net ([76.96.27.211]:33141 "EHLO QMTA11.emeryville.ca.mail.comcast.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751790AbZGXEKW (ORCPT ); Fri, 24 Jul 2009 00:10:22 -0400 In-Reply-To: <20090724040700.30709.31473.stgit@localhost.localdomain> Sender: netdev-owner@vger.kernel.org List-ID: From: Alexander Duyck This change makes it so that we use buffer_info->dma instead of shinfo->nr_frags to determine if we need to unmap a received skb. By doing this we can avoid a cache miss on small packets since the buffer_info structure should already be prefetched. Signed-off-by: Alexander Duyck Signed-off-by: Jeff Kirsher --- drivers/net/igb/igb_main.c | 30 ++++++++++++++++++------------ 1 files changed, 18 insertions(+), 12 deletions(-) diff --git a/drivers/net/igb/igb_main.c b/drivers/net/igb/igb_main.c index 2ffb51d..12d8683 100644 --- a/drivers/net/igb/igb_main.c +++ b/drivers/net/igb/igb_main.c @@ -4538,6 +4538,20 @@ static inline void igb_rx_checksum_adv(struct igb_adapter *adapter, adapter->hw_csum_good++; } +static inline u16 igb_get_hlen(struct igb_adapter *adapter, + union e1000_adv_rx_desc *rx_desc) +{ + /* HW will not DMA in data larger than the given buffer, even if it + * parses the (NFS, of course) header to be larger. In that case, it + * fills the header buffer and spills the rest into the page. + */ + u16 hlen = (le16_to_cpu(rx_desc->wb.lower.lo_dword.hdr_info) & + E1000_RXDADV_HDRBUFLEN_MASK) >> E1000_RXDADV_HDRBUFLEN_SHIFT; + if (hlen > adapter->rx_ps_hdr_size) + hlen = adapter->rx_ps_hdr_size; + return hlen; +} + static bool igb_clean_rx_irq_adv(struct igb_ring *rx_ring, int *work_done, int budget) { @@ -4552,7 +4566,8 @@ static bool igb_clean_rx_irq_adv(struct igb_ring *rx_ring, int cleaned_count = 0; unsigned int total_bytes = 0, total_packets = 0; unsigned int i; - u32 length, hlen, staterr; + u32 staterr; + u16 length; i = rx_ring->next_to_clean; buffer_info = &rx_ring->buffer_info[i]; @@ -4589,17 +4604,8 @@ static bool igb_clean_rx_irq_adv(struct igb_ring *rx_ring, goto send_up; } - /* HW will not DMA in data larger than the given buffer, even - * if it parses the (NFS, of course) header to be larger. In - * that case, it fills the header buffer and spills the rest - * into the page. - */ - hlen = (le16_to_cpu(rx_desc->wb.lower.lo_dword.hdr_info) & - E1000_RXDADV_HDRBUFLEN_MASK) >> E1000_RXDADV_HDRBUFLEN_SHIFT; - if (hlen > adapter->rx_ps_hdr_size) - hlen = adapter->rx_ps_hdr_size; - - if (!skb_shinfo(skb)->nr_frags) { + if (buffer_info->dma) { + u16 hlen = igb_get_hlen(adapter, rx_desc); pci_unmap_single(pdev, buffer_info->dma, adapter->rx_ps_hdr_size, PCI_DMA_FROMDEVICE);