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From:   Oleksandr Mazur <oleksandr.mazur@plvision.eu>
To:     Jakub Kicinski <kuba@kernel.org>, Ido Schimmel <idosch@idosch.org>
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        "jiri@nvidia.com" <jiri@nvidia.com>,
        "davem@davemloft.net" <davem@davemloft.net>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH net-next] net: core: devlink: add new trap action
 HARD_DROP
Thread-Topic: [PATCH net-next] net: core: devlink: add new trap action
 HARD_DROP
Thread-Index: AQHW8JmdV3Ghn6zeuUSyZ1aU9R+t1A==
Date:   Fri, 22 Jan 2021 08:36:01 +0000
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On Thu, 21 Jan 2021 14:21:52 +0200 Ido Schimmel wrote:=0A=
> On Thu, Jan 21, 2021 at 01:29:37PM +0200, Oleksandr Mazur wrote:=0A=
> > Add new trap action HARD_DROP, which can be used by the=0A=
> > drivers to register traps, where it's impossible to get=0A=
> > packet reported to the devlink subsystem by the device=0A=
> > driver, because it's impossible to retrieve dropped packet=0A=
> > from the device itself.=0A=
> > In order to use this action, driver must also register=0A=
> > additional devlink operation - callback that is used=0A=
> > to retrieve number of packets that have been dropped by=0A=
> > the device.=A0 =0A=
> =0A=
> Are these global statistics about number of packets the hardware dropped=
=0A=
> for a specific reason or are these per-port statistics?=0A=
> =0A=
> It's a creative use of devlink-trap interface, but I think it makes=0A=
> sense. Better to re-use an existing interface than creating yet another=
=0A=
> one.=0A=
=0A=
> Not sure if I agree, if we can't trap why is it a trap?=0A=
> It's just a counter.=0A=
=0A=
It's just another ACTION for trap item. Action however can be switched, e.g=
. from HARD_DROP to MIRROR.=0A=
=0A=
The thing is to be able to configure specific trap to be dropped, and provi=
de a way for the device to report back how many packets have been dropped.=
=0A=
If device is able to report the packet itself, then devlink would be in cha=
rge of counting. If not, there should be a way to retrieve these statistics=
 from the devlink.=