Subject: Re: [PATCH v4 bpf-next 6/9] bpf: cpumap: implement XDP_REDIRECT for eBPF programs attached to map entries

From: Jesper Dangaard Brouer <[email-masked]>
Date: Fri, 26 Jun 2020 12:06:32 +0200

On Wed, 24 Jun 2020 17:33:55 +0200
Lorenzo Bianconi <[email-masked]> wrote:

> diff --git a/include/net/xdp.h b/include/net/xdp.h
> index 83b9e0142b52..5be0d4d65b94 100644
> --- a/include/net/xdp.h
> +++ b/include/net/xdp.h
> @@ -99,6 +99,7 @@ struct xdp_frame {
>  };
>  
>  struct xdp_cpumap_stats {
> +	unsigned int redirect;
>  	unsigned int pass;
>  	unsigned int drop;
>  };
> diff --git a/include/trace/events/xdp.h b/include/trace/events/xdp.h
> index e2c99f5bee39..cd24e8a59529 100644
> --- a/include/trace/events/xdp.h
> +++ b/include/trace/events/xdp.h
> @@ -190,6 +190,7 @@ TRACE_EVENT(xdp_cpumap_kthread,
>  		__field(int, sched)
>  		__field(unsigned int, xdp_pass)
>  		__field(unsigned int, xdp_drop)
> +		__field(unsigned int, xdp_redirect)
>  	),
>  
>  	TP_fast_assign(
> @@ -201,18 +202,19 @@ TRACE_EVENT(xdp_cpumap_kthread,
>  		__entry->sched	= sched;
>  		__entry->xdp_pass	= xdp_stats->pass;
>  		__entry->xdp_drop	= xdp_stats->drop;
> +		__entry->xdp_redirect	= xdp_stats->redirect;
>  	),

Let me stress, that I think can do this in a followup patch (but before
a release).

I'm considering that we should store/give a pointer to xdp_stats
(struct xdp_cpumap_stats) and let the BPF tracing program do the
"decoding"/struct access to get these values.  (We will go from storing
12 bytes to 8 bytes (on 64-bit), so I don't expect much gain).

>  	TP_printk("kthread"
>  		  " cpu=%d map_id=%d action=%s"
>  		  " processed=%u drops=%u"
>  		  " sched=%d"
> -		  " xdp_pass=%u xdp_drop=%u",
> +		  " xdp_pass=%u xdp_drop=%u xdp_redirect=%u",
>  		  __entry->cpu, __entry->map_id,
>  		  __print_symbolic(__entry->act, __XDP_ACT_SYM_TAB),
>  		  __entry->processed, __entry->drops,
>  		  __entry->sched,
> -		  __entry->xdp_pass, __entry->xdp_drop)
> +		  __entry->xdp_pass, __entry->xdp_drop, __entry->xdp_redirect)
>  );
>  

-- 
Best regards,
  Jesper Dangaard Brouer
  MSc.CS, Principal Kernel Engineer at Red Hat
  LinkedIn: http://www.linkedin.com/in/brouer