netdev - Re: [PATCH net-next] route: Add a new fib_multipath_hash

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Message-ID: <8feb69cd-bc86-a2fc-646d-0349275e1736@cogentembedded.com>
Date:   Fri, 22 Feb 2019 12:06:57 +0300
From:   Sergei Shtylyov <sergei.shtylyov@...entembedded.com>
To:     wenxu@...oud.cn, davem@...emloft.net
Cc:     netdev@...r.kernel.org
Subject: Re: [PATCH net-next] route: Add a new fib_multipath_hash_policy base
 on cpu id for tunnel packet

Hello!

On 22.02.2019 6:52, wenxu@...oud.cn wrote:

> From: wenxu <wenxu@...oud.cn>
> 
> Current fib_multipath_hash_policy can make hash based on the L3 or
> L4. But it only work on the outer IP. So a specific tunnel always
> has the same hash value. But a specific tunnel may contain so many
> inner connection. However there is no good ways for tunnel packet.

    Connections? Way?

> A specific tunnel route based on the percpu dst_cache, It will not
> lookup route table each packet.

    For each packet?

> This patch provide a based cpu id hash policy. The different
> connection run on differnt cpu and There will differnet hash

    Different. Will be?

> value for percpu dst_cache.
> 
> Signed-off-by: wenxu <wenxu@...oud.cn>
> ---
>   net/ipv4/route.c           | 6 ++++++
>   net/ipv4/sysctl_net_ipv4.c | 2 +-
>   2 files changed, 7 insertions(+), 1 deletion(-)
> 
> diff --git a/net/ipv4/route.c b/net/ipv4/route.c
> index ecc12a7..6cf2fd4 100644
> --- a/net/ipv4/route.c
> +++ b/net/ipv4/route.c
[...]
> @@ -1834,6 +1835,8 @@ int fib_multipath_hash(const struct net *net, const struct flowi4 *fl4,
>   			hash_keys.addrs.v4addrs.dst = fl4->daddr;
>   		}
>   		break;
> +	case 2:
> +		cpu = smp_processor_id() + 1;

    Should be a comment /* fall through */ if this fall thru isn't in error.

>   	case 1:
>   		/* skb is currently provided only when forwarding */
>   		if (skb) {
[...]

MBR, Sergei