From: Kurt Kanzenbach <kurt@linutronix.de>
To: Vladimir Oltean <vladimir.oltean@nxp.com>, netdev@vger.kernel.org
Cc: andrew@lunn.ch, f.fainelli@gmail.com, vivien.didelot@gmail.com,
kuba@kernel.org, Christian Eggers <ceggers@arri.de>
Subject: Re: [PATCH v2 net-next 01/12] net: dsa: implement a central TX reallocation procedure
Date: Fri, 30 Oct 2020 07:41:05 +0100 [thread overview]
Message-ID: <87imas9pxa.fsf@kurt> (raw)
In-Reply-To: <20201030014910.2738809-2-vladimir.oltean@nxp.com>
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On Fri Oct 30 2020, Vladimir Oltean wrote:
> At the moment, taggers are left with the task of ensuring that the skb
> headers are writable (which they aren't, if the frames were cloned for
> TX timestamping, for flooding by the bridge, etc), and that there is
> enough space in the skb data area for the DSA tag to be pushed.
>
> Moreover, the life of tail taggers is even harder, because they need to
> ensure that short frames have enough padding, a problem that normal
> taggers don't have.
>
> The principle of the DSA framework is that everything except for the
> most intimate hardware specifics (like in this case, the actual packing
> of the DSA tag bits) should be done inside the core, to avoid having
> code paths that are very rarely tested.
>
> So provide a TX reallocation procedure that should cover the known needs
> of DSA today.
>
> Note that this patch also gives the network stack a good hint about the
> headroom/tailroom it's going to need. Up till now it wasn't doing that.
> So the reallocation procedure should really be there only for the
> exceptional cases, and for cloned packets which need to be unshared.
> The tx_reallocs counter should prove that.
>
> Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
> Tested-by: Christian Eggers <ceggers@arri.de> # For tail taggers only
Tested-by: Kurt Kanzenbach <kurt@linutronix.de>
I'll wait with the hellcreek series until this is merged.
Thanks,
Kurt
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next prev parent reply other threads:[~2020-10-30 6:41 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-30 1:48 [PATCH v2 net-next 00/12] Generic TX reallocation for DSA Vladimir Oltean
2020-10-30 1:48 ` [PATCH v2 net-next 01/12] net: dsa: implement a central TX reallocation procedure Vladimir Oltean
2020-10-30 6:41 ` Kurt Kanzenbach [this message]
2020-11-01 1:00 ` Jakub Kicinski
2020-11-01 1:14 ` Vladimir Oltean
2020-11-01 1:37 ` Vladimir Oltean
2020-11-02 19:57 ` Jakub Kicinski
2020-10-30 1:49 ` [PATCH v2 net-next 02/12] net: dsa: tag_ksz: don't allocate additional memory for padding/tagging Vladimir Oltean
2020-10-30 1:49 ` [PATCH v2 net-next 03/12] net: dsa: trailer: " Vladimir Oltean
2020-10-30 1:49 ` [PATCH v2 net-next 04/12] net: dsa: tag_qca: let DSA core deal with TX reallocation Vladimir Oltean
2020-10-30 1:49 ` [PATCH v2 net-next 05/12] net: dsa: tag_ocelot: " Vladimir Oltean
2020-10-30 1:49 ` [PATCH v2 net-next 06/12] net: dsa: tag_mtk: " Vladimir Oltean
2020-10-30 1:49 ` [PATCH v2 net-next 07/12] net: dsa: tag_lan9303: " Vladimir Oltean
2020-10-30 1:49 ` [PATCH v2 net-next 08/12] net: dsa: tag_edsa: " Vladimir Oltean
2020-10-30 1:49 ` [PATCH v2 net-next 09/12] net: dsa: tag_brcm: " Vladimir Oltean
2020-10-30 1:49 ` [PATCH v2 net-next 10/12] net: dsa: tag_dsa: " Vladimir Oltean
2020-10-30 1:49 ` [PATCH v2 net-next 11/12] net: dsa: tag_gswip: " Vladimir Oltean
2020-10-30 1:49 ` [PATCH v2 net-next 12/12] net: dsa: tag_ar9331: " Vladimir Oltean
2020-10-30 9:21 ` Oleksij Rempel
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