src/patches/suse-2.6.27.39/patches.drivers/ixgbe_pagesize_fix.patch

   1 From: Jesse Brandeburg <jesse.brandeburg@intel.com>
   2 Subject: ixgbe bad performance with 64kB pages and large MTU
   3 Acked-by: Karsten Keil <kkeil@suse.de>
   4 Reference: bnc#480109
   5
   6 it was pointed out on the list that ixgbe was failing when using 64kB pages
   7 and large 16kB MTU.
   8
   9 since with a 64kB PAGE_SIZE MAX_SKB_FRAGS = 3, the way the driver was
  10 configuring page usage was assuming 2kB is half a page, and was only
  11 ever dmaing that much data to a half page.
  12
  13 (16kB - header size) / 2048 = 7 or 8 pages, which would far exceed 3
  14
  15 adjust the driver to account for these large pages, the hardware can
  16 support DMA to up to 16kB for each descriptor.
  17
  18 Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
  19 CC: Breno Leitao <leitao@linux.vnet.ibm.com>
  20 Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
  21 ---
  22
  23  drivers/net/ixgbe/ixgbe.h      |    1 +
  24  drivers/net/ixgbe/ixgbe_main.c |    9 ++++++++-
  25  2 files changed, 9 insertions(+), 1 deletion(-)
  26
  27 --- a/drivers/net/ixgbe/ixgbe.h
  28 +++ b/drivers/net/ixgbe/ixgbe.h
  29 @@ -77,6 +77,7 @@
  30  #define IXGBE_RXBUFFER_128   128    /* Used for packet split */
  31  #define IXGBE_RXBUFFER_256   256    /* Used for packet split */
  32  #define IXGBE_RXBUFFER_2048  2048
  33 +#define IXGBE_MAX_RXBUFFER   16384  /* largest size for a single descriptor */
  34
  35  #define IXGBE_RX_HDR_SIZE IXGBE_RXBUFFER_256
  36
  37 --- a/drivers/net/ixgbe/ixgbe_main.c
  38 +++ b/drivers/net/ixgbe/ixgbe_main.c
  39 @@ -1537,7 +1537,14 @@ static void ixgbe_configure_srrctl(struc
  40         srrctl &= ~IXGBE_SRRCTL_BSIZEPKT_MASK;
  41
  42         if (adapter->flags & IXGBE_FLAG_RX_PS_ENABLED) {
  43 -               srrctl |= IXGBE_RXBUFFER_2048 >> IXGBE_SRRCTL_BSIZEPKT_SHIFT;
  44 +               u16 bufsz = IXGBE_RXBUFFER_2048;
  45 +               /* grow the amount we can receive on large page machines */
  46 +               if (bufsz < (PAGE_SIZE / 2))
  47 +                       bufsz = (PAGE_SIZE / 2);
  48 +               /* cap the bufsz at our largest descriptor size */
  49 +               bufsz = min((u16)IXGBE_MAX_RXBUFFER, bufsz);
  50 +
  51 +               srrctl |= bufsz >> IXGBE_SRRCTL_BSIZEPKT_SHIFT;
  52                 srrctl |= IXGBE_SRRCTL_DESCTYPE_HDR_SPLIT_ALWAYS;
  53                 srrctl |= ((IXGBE_RX_HDR_SIZE <<
  54                             IXGBE_SRRCTL_BSIZEHDRSIZE_SHIFT) &