[Intel-wired-lan] [next PATCH S28 08/15] i40e/i40evf: avoid atomics

[Bowers, AndrewX]

> -----Original Message-----
> From: Intel-wired-lan [mailto:intel-wired-lan-bounces at lists.osuosl.org] On
> Behalf Of Joshua Hay
> Sent: Friday, January 15, 2016 2:33 PM
> To: intel-wired-lan at lists.osuosl.org
> Subject: [Intel-wired-lan] [next PATCH S28 08/15] i40e/i40evf: avoid atomics
> 
> From: Mitch Williams <mitch.a.williams at intel.com>
> 
> In the case where we have a page fully used by receive data, we need to
> release the page fully to the stack. Instead of calling get_page (which
> increments the page count) followed by free_page (which decrements the
> page count), just donate our reference to the stack. Although this donation is
> not tax deductable, it does allow us to avoid two very expensive atomic
> operations that reverse each other.
> 
> Signed-off-by: Mitch Williams <mitch.a.williams at intel.com>
> Change-ID: If70739792d5748995fc175ec92ac2171ed4ad8fc
> ---
> Testing Hints: make sure receive traffic is stable under heavy load with
> packet split enabled, and that no data corruption is seen.
> 
>  drivers/net/ethernet/intel/i40e/i40e_txrx.c   | 21 +++++++++++++--------
>  drivers/net/ethernet/intel/i40evf/i40e_txrx.c | 21 +++++++++++++--------
>  2 files changed, 26 insertions(+), 16 deletions(-)

Tested-by: Andrew Bowers <andrewx.bowers at intel.com>
Patch code changes correctly applied, heavy load traffic stable, no corruption observed