ACK/cmnt: [PATCH 0/2][SRU][B] i40e: xps management broken when > 64 queues/cpus

[Kleber Souza]

On 3/26/19 9:30 AM, Nivedita Singhvi wrote:
> BugLink: https://bugs.launchpad.net/bugs/1820948
> 
> [Impact]
> Transmit packet steering (xps) settings don't work when
> the number of queues (cpus) is higher than 64. This is
> currently still an issue on the 4.15 kernel (Xenial -hwe
> and Bionic kernels).
> 
> It was fixed in Intel's i40e driver version 2.7.11 and
> in 4.16-rc1 mainline Linux (i.e. Cosmic, Disco have fix).
> 
> Fix
> -----
> The following commit fixes this issue (as identified
> by Lihong Yang in discussion with Intel i40e team):
> 
> "i40e: Fix the number of queues available to be mapped for use"
> Commit: bc6d33c8d93f5999920e97a8c6330b8910053d4f
> 
> It requires the following commit as well: 
> 
> i40e: Do not allow use more TC queue pairs than MSI-X vectors exist
> Commit:	1563f2d2e01242f05dd523ffd56fe104bc1afd58
> 
> 
> [Test Case]
> 1. Kernel version: Bionic/Xenial -hwe: any 4.15 kernel
>    i40e driver version: 2.1.14-k
>    Any system with > 64 CPUs
> 
> 2. For any queue 0 - 63, you can read/set tx xps:
> 
> echo ffffffff > /sys/class/net/eth2/queues/tx-63/xps_cpus
> echo $?
> 0
> cat /sys/class/net/eth2/queues/tx-63/xps_cpus
> 00,00000000,ffffffff
> 
>   But for any queue number > 63, we see this error:
> 
> echo ffffffff > /sys/class/net/eth2/queues/tx-64/xps_cpus
> echo: write error: Invalid argument
> 
> cat /sys/class/net/eth2/queues/tx-64/xps_cpus
> cat: /sys/class/net/eth2/queues/tx-64/xps_cpus: Invalid argument
> 
> 
> Amritha Nambiar (1):
>   i40e: Fix the number of queues available to be mapped for use
> 
> Paweł Jabłoński (1):
>   i40e: Do not allow use more TC queue pairs than MSI-X vectors exist
> 
>  drivers/net/ethernet/intel/i40e/i40e_main.c | 29 ++++++++++++---------
>  1 file changed, 17 insertions(+), 12 deletions(-)
> 

With the "cherry picked" line fixed as pointed out by Juerg:

Acked-by: Kleber Sacilotto de Souza <kleber.souza at canonical.com>