Re: [RFC/PATCH net-next v3 0/8] allow user to offload tc action to net device
From: Vlad Buslov <hidden>
Date: 2021-11-01 08:01:41
On Sun 31 Oct 2021 at 15:40, Jamal Hadi Salim [off-list ref] wrote:
On 2021-10-31 05:50, Oz Shlomo wrote:quoted
On 10/28/2021 2:06 PM, Simon Horman wrote:quoted
Baowen Zheng says: Allow use of flow_indr_dev_register/flow_indr_dev_setup_offload to offload tc actions independent of flows. The motivation for this work is to prepare for using TC police action instances to provide hardware offload of OVS metering feature - which calls for policers that may be used by multiple flows and whose lifecycle is independent of any flows that use them. This patch includes basic changes to offload drivers to return EOPNOTSUPP if this feature is used - it is not yet supported by any driver. Tc cli command to offload and quote an action: tc qdisc del dev $DEV ingress && sleep 1 || true tc actions delete action police index 99 || true tc qdisc add dev $DEV ingress tc qdisc show dev $DEV ingress tc actions add action police index 99 rate 1mbit burst 100k skip_sw tc actions list action police tc filter add dev $DEV protocol ip parent ffff: flower ip_proto tcp action police index 99 tc -s -d filter show dev $DEV protocol ip parent ffff: tc filter add dev $DEV protocol ipv6 parent ffff: flower skip_sw ip_proto tcp action police index 99 tc -s -d filter show dev $DEV protocol ipv6 parent ffff: tc actions list action police tc qdisc del dev $DEV ingress && sleep 1 tc actions delete action police index 99 tc actions list action policeActions are also (implicitly) instantiated when filters are created. In the following example the mirred action instance (created by the first filter) is shared by the second filter: tc filter add dev $DEV1 proto ip parent ffff: flower \ ip_proto tcp action mirred egress redirect dev $DEV3 tc filter add dev $DEV2 proto ip parent ffff: flower \ ip_proto tcp action mirred index 1I sure hope this is supported. At least the discussions so far are a nod in that direction... I know there is hardware that is not capable of achieving this (little CPE type devices) but lets not make that the common case.
Looks like it isn't supported in this change since tcf_action_offload_add() is only called by tcf_action_init() when BIND flag is not set (the flag is always set when called from cls code). Moreover, I don't think it is good idea to support such use-case because that would require to increase number of calls to driver offload infrastructure from 1 per filter to 1+number_of_actions, which would significantly impact insertion rate.