netdev - Re: [patch net-next v2 0/9] mlxsw: implement port mirroring offload

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Message-ID: <20160722193817.GC2050@nanopsycho.orion>
Date:	Fri, 22 Jul 2016 21:38:17 +0200
From:	Jiri Pirko <jiri@...nulli.us>
To:	Florian Fainelli <f.fainelli@...il.com>
Cc:	netdev@...r.kernel.org, davem@...emloft.net, yotamg@...lanox.com,
	eladr@...lanox.com, idosch@...lanox.com, nogahf@...lanox.com,
	ogerlitz@...lanox.com, jhs@...atatu.com,
	Andrew Lunn <andrew@...n.ch>
Subject: Re: [patch net-next v2 0/9] mlxsw: implement port mirroring offload

Fri, Jul 22, 2016 at 09:26:30PM CEST, f.fainelli@...il.com wrote:
>On 07/22/2016 12:20 PM, Jiri Pirko wrote:
>> Fri, Jul 22, 2016 at 08:24:31PM CEST, f.fainelli@...il.com wrote:
>>> On 07/21/2016 03:03 AM, Jiri Pirko wrote:
>>>> From: Jiri Pirko <jiri@...lanox.com>
>>>>
>>>> This patchset introduces tc matchall classifier and its offload
>>>> to Spectrum hardware. In combination with mirred action, defined port mirroring
>>>> setup is offloaded by mlxsw/spectrum driver.
>>>>
>>>> The commands used for creating mirror ports:
>>>>
>>>> # ingress mirroring using matchall
>>>> tc qdisc  add dev eth25 handle ffff: ingress
>>>> tc filter add dev eth25 parent ffff:            \
>>>>         matchall skip_sw                        \
>>>>         action mirred egress mirror             \
>>>>         dev eth27
>>>>
>>>> # egress mirroring using matchall
>>>> tc qdisc add dev eth25 handle 1: root prio
>>>> tc filter add dev eth25 parent 1:               \
>>>>         matchall skip_sw                        \
>>>>         action mirred egress mirror             \
>>>>         dev eth27
>>>
>>> Is there any logic that guards against the following cases where the
>>> target device is:
>>>
>>> - outside of the switch hardware/cluster (which would imply going
>>> through software)?
>> 
>> In that case only kernel (slow) path can be used. Not possible to
>> offload of course.
>
>So then what happens if I target a device that is outside of the switch,
>do we get an error like -EOPNOTSUPP, or this just silently succeeed, but
>nothing happens?

As you can see, the check in mlxsw_sp_port_add_cls_matchall_mirror
returns -ENOTSUPP. That is handled in mall_change and is skip_sw is not
set, the rule is installed only in sw. This behaviour is aligned with
the rest of the ndo_setup_tc users, like cls_u32 and cls_flower.


>
>> 
>> 
>>> - has a downstream speed which is lower than the mirrored device?
>> 
>> The default behaviour is "strict" which means that if the mirrored
>> packet can't be send, the packet is dropped. That is aligned with the
>> behaviour of act_mirred.
>
>What determines if the packet can be sent or not?

If there are free buffers for the packet to be send to mirroring device,
the original packet is sent and the mirrored as well.



>
>> 
>> 
>>>
>>> this might already be in place for 1), I just could not locate it, thanks!
>>>
>>>>
>>>> These patches contain:
>>>>  - Resource query implementation
>>>>  - Hardware port mirorring support for spectrum.
>>>>  - Definition of the matchall traffic classifier.
>>>>  - General support for hw-offloading for that classifier.
>>>>  - Specific spectrum implementaion for matchall offloading.
>>>>
>>>> ---
>>>> v1->v2:
>>>>  - couple of minor style fixes
>>>>
>>>> Jiri Pirko (1):
>>>>   net/sched: introduce Match-all classifier
>>>>
>>>> Nogah Frankel (2):
>>>>   mlxsw: pci: Add resources query implementation.
>>>>   mlxsw: pci: Add max span resources to resources query
>>>>
>>>> Yotam Gigi (6):
>>>>   net/sched: Add match-all classifier hw offloading.
>>>>   mlxsw: reg: Add Shared Buffer Internal Buffer register
>>>>   mlxsw: reg: Add Monitoring Port Analyzer Table register
>>>>   mlxsw: reg: Add the Monitoring Port Analyzer register
>>>>   net/sched: act_mirred: Add helper inlines to access tcf_mirred info.
>>>>   mlxsw: spectrum: Add support in matchall mirror TC offloading
>>>>
>>>>  drivers/net/ethernet/mellanox/mlxsw/cmd.h      |  32 ++
>>>>  drivers/net/ethernet/mellanox/mlxsw/core.c     |  10 +-
>>>>  drivers/net/ethernet/mellanox/mlxsw/core.h     |  11 +-
>>>>  drivers/net/ethernet/mellanox/mlxsw/pci.c      |  64 +++-
>>>>  drivers/net/ethernet/mellanox/mlxsw/reg.h      | 162 +++++++++
>>>>  drivers/net/ethernet/mellanox/mlxsw/spectrum.c | 465 ++++++++++++++++++++++++-
>>>>  drivers/net/ethernet/mellanox/mlxsw/spectrum.h |  44 +++
>>>>  drivers/net/ethernet/mellanox/mlxsw/switchx2.c |   1 +
>>>>  include/linux/netdevice.h                      |   2 +
>>>>  include/net/pkt_cls.h                          |  11 +
>>>>  include/net/tc_act/tc_mirred.h                 |   9 +
>>>>  include/uapi/linux/pkt_cls.h                   |  12 +
>>>>  net/sched/Kconfig                              |  10 +
>>>>  net/sched/Makefile                             |   1 +
>>>>  net/sched/cls_matchall.c                       | 318 +++++++++++++++++
>>>>  15 files changed, 1148 insertions(+), 4 deletions(-)
>>>>  create mode 100644 net/sched/cls_matchall.c
>>>>
>>>
>>>
>>> -- 
>>> Florian
>
>
>-- 
>Florian