netdev - Re: [PATCH] net: bonding: Fix transmit load balancing in balance-alb mode

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Date:   Wed, 6 Sep 2017 22:45:36 +0000
From:   Kosuke Tatsukawa <tatsu@...jp.nec.com>
To:     Jay Vosburgh <j.vosburgh@...il.com>,
        Veaceslav Falico <vfalico@...il.com>,
        Andy Gospodarek <andy@...yhouse.net>
CC:     "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Reinis Rozitis <r@...e.lv>
Subject: Re: [PATCH] net: bonding: Fix transmit load balancing in
 balance-alb mode 

Reinis Rozitis reported that tlb_dynamic_lb was still 0 in balance-alb
mode even when using linux-4.12.10 kernels, which includes this patch.

It turned out that my previous patch only fixed the case when
balance-alb mode was specified as bonding module parameter, and not when
balance-alb mode was set using /sys/class/net/*/bonding/mode (the most
common usage).  In the latter case, tlb_dynamic_lb was set up according
to the default mode of the bonding interface, which happens to be
balance-rr.

I'll send another patch to address this case.

In the meantime, a workaround for this issue is to specify balance-tlb
mode as a module parameter for bonding.  This will change the value of
tlb_balance_lb to 1, and make balance-alb work like pre-4.12 kernels.

Best regards.


> balance-alb mode used to have transmit dynamic load balancing feature
> enabled by default.  However, transmit dynamic load balancing no longer
> works in balance-alb after commit 8b426dc54cf4 ("bonding: remove
> hardcoded value").
> 
> Both balance-tlb and balance-alb use the function bond_do_alb_xmit() to
> send packets.  This function uses the parameter tlb_dynamic_lb.
> tlb_dynamic_lb used to have the default value of 1 for balance-alb, but
> now the value is set to 0 except in balance-tlb.
> 
> Re-enable transmit dyanmic load balancing by initializing tlb_dynamic_lb
> for balance-alb similar to balance-tlb.
> 
> Signed-off-by: Kosuke Tatsukawa <tatsu@...jp.nec.com>
> Cc: stable@...r.kernel.org
> ---
>  drivers/net/bonding/bond_main.c |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
> 
> diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
> index 14ff622..181839d 100644
> --- a/drivers/net/bonding/bond_main.c
> +++ b/drivers/net/bonding/bond_main.c
> @@ -4596,7 +4596,7 @@ static int bond_check_params(struct bond_params *params)
>  	}
>  	ad_user_port_key = valptr->value;
>  
> -	if (bond_mode == BOND_MODE_TLB) {
> +	if ((bond_mode == BOND_MODE_TLB) || (bond_mode == BOND_MODE_ALB)) {
>  		bond_opt_initstr(&newval, "default");
>  		valptr = bond_opt_parse(bond_opt_get(BOND_OPT_TLB_DYNAMIC_LB),
>  					&newval);
---
Kosuke TATSUKAWA  | 1st Platform Software Division
                  | NEC Solution Innovators
                  | tatsu@...jp.nec.com