netdev - Re: [PATCH net-next v3 06/16] net: bridge: Add a tracepoint for MDB overflows

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Date:   Fri, 3 Feb 2023 10:58:12 +0200
From:   Nikolay Aleksandrov <razor@...ckwall.org>
To:     Petr Machata <petrm@...dia.com>,
        "David S. Miller" <davem@...emloft.net>,
        Eric Dumazet <edumazet@...gle.com>,
        Jakub Kicinski <kuba@...nel.org>,
        Paolo Abeni <pabeni@...hat.com>,
        Roopa Prabhu <roopa@...dia.com>, netdev@...r.kernel.org
Cc:     bridge@...ts.linux-foundation.org,
        Ido Schimmel <idosch@...dia.com>,
        Steven Rostedt <rostedt@...dmis.org>,
        linux-trace-kernel@...r.kernel.org
Subject: Re: [PATCH net-next v3 06/16] net: bridge: Add a tracepoint for MDB
 overflows

On 02/02/2023 19:59, Petr Machata wrote:
> The following patch will add two more maximum MDB allowances to the global
> one, mcast_hash_max, that exists today. In all these cases, attempts to add
> MDB entries above the configured maximums through netlink, fail noisily and
> obviously. Such visibility is missing when adding entries through the
> control plane traffic, by IGMP or MLD packets.
> 
> To improve visibility in those cases, add a trace point that reports the
> violation, including the relevant netdevice (be it a slave or the bridge
> itself), and the MDB entry parameters:
> 
> 	# perf record -e bridge:br_mdb_full &
> 	# [...]
> 	# perf script | cut -d: -f4-
> 	 dev v2 af 2 src ::ffff:0.0.0.0 grp ::ffff:239.1.1.112/00:00:00:00:00:00 vid 0
> 	 dev v2 af 10 src :: grp ff0e::112/00:00:00:00:00:00 vid 0
> 	 dev v2 af 2 src ::ffff:0.0.0.0 grp ::ffff:239.1.1.112/00:00:00:00:00:00 vid 10
> 	 dev v2 af 10 src 2001:db8:1::1 grp ff0e::1/00:00:00:00:00:00 vid 10
> 	 dev v2 af 2 src ::ffff:192.0.2.1 grp ::ffff:239.1.1.1/00:00:00:00:00:00 vid 10
> 
> CC: Steven Rostedt <rostedt@...dmis.org>
> CC: linux-trace-kernel@...r.kernel.org
> Signed-off-by: Petr Machata <petrm@...dia.com>
> Reviewed-by: Steven Rostedt (Google) <rostedt@...dmis.org>
> ---
> 
> Notes:
>     v2:
>     - Report IPv4 as an IPv6-mapped address through the IPv6 buffer
>       as well, to save ring buffer space.
> 
>  include/trace/events/bridge.h | 58 +++++++++++++++++++++++++++++++++++
>  net/core/net-traces.c         |  1 +
>  2 files changed, 59 insertions(+)
> 

Acked-by: Nikolay Aleksandrov <razor@...ckwall.org>