Hi Jiri,

Commenting on generalities - will comment on code later:

On 17-07-10 02:51 PM, Jiri Pirko wrote:
From: Jiri Pirko <j...@mellanox.com>

Currently the filters added to qdiscs are independent. So for example if you
have 2 netdevices and you create ingress qdisc on both and you want to add
identical filter rules both, you need to add them twice. This patchset
makes this easier and mainly saves resources allowing to share all filters
within a qdisc - I call it a "filter block". Also this helps to save
resources when we do offload to hw for example to expensive TCAM.

So back to the example. First, we create 2 qdiscs. Both will share
block number 22. "22" is just an identification. If we don't pass any
block number, a new one will be generated by kernel:

$ tc qdisc add dev ens7 ingress block 22
                                 ^^^^^^^^
$ tc qdisc add dev ens8 ingress block 22


Above makes intuitive sense.


                                  ^^^^^^^^

Now if we list the qdiscs, we will see the block index in the output:
qdisc fq_codel 0: dev ens7 root refcnt 2 limit 10240p flows 1024 quantum 1514 
target 5.0ms interval 100.0ms memory_limit 32Mb ecn
  Sent 9014 bytes 99 pkt (dropped 0, overlimits 0 requeues 0)
  backlog 0b 0p requeues 0
   maxpacket 0 drop_overlimit 0 new_flow_count 0 ecn_mark 0
   new_flows_len 0 old_flows_len 0
qdisc ingress ffff: dev ens7 parent ffff:fff1 block 22
                                               ^^^^^^^^
  Sent 4592 bytes 58 pkt (dropped 0, overlimits 0 requeues 0)
  backlog 0b 0p requeues 0
qdisc fq_codel 0: dev ens8 root refcnt 2 limit 10240p flows 1024 quantum 1514 
target 5.0ms interval 100.0ms memory_limit 32Mb ecn
  Sent 17022 bytes 307 pkt (dropped 0, overlimits 0 requeues 0)
  backlog 0b 0p requeues 0
   maxpacket 0 drop_overlimit 0 new_flow_count 0 ecn_mark 0
   new_flows_len 0 old_flows_len 0
qdisc ingress ffff: dev ens8 parent ffff:fff1 block 22
                                               ^^^^^^^^
  Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0)
  backlog 0b 0p requeues 0


So does this.


Now we can add filter to any of qdiscs sharing the same block:

$ tc filter add dev ens7 parent ffff: protocol ip pref 25 flower dst_ip 
192.168.0.0/16 action drop


So for backward compat - this also makes sense. But:
it does make sense to create new syntax for adding
filters and actions:

tc filter add block 22 protocol ip pref 25 flower \
  dst_ip 192.168.0.0/16 action drop

Coordinates of the filter block before were:

<ifindex>, <parent>, [handle]

You should be able to abuse struct tcmsg ifindex to represent block #
as long as you set parent to be something meaningful that is
identified "block coordinate" via TC_H_XXX (pick something safe not
in use by ingress or egress; look at: uapi/linux/pkt_sched.h)


We will see the same output if we list filters for ens7 and ens8, including 
stats:

$ tc -s filter show dev ens7 root
filter parent ffff: protocol ip pref 25 flower
filter parent ffff: protocol ip pref 25 flower handle 0x1
   eth_type ipv4
   dst_ip 192.168.1.0/24
         action order 1: gact action drop
          random type none pass val 0
          index 3 ref 1 bind 1 installed 10201 sec used 10150 sec
         Action statistics:
         Sent 4200 bytes 50 pkt (dropped 50, overlimits 0 requeues 0)
         backlog 0b 0p requeues 0

$ tc -s filter show dev ens8 root
filter dev ens7 parent ffff: protocol ip pref 25 flower
filter dev ens7 parent ffff: protocol ip pref 25 flower handle 0x1
   eth_type ipv4
   dst_ip 192.168.1.0/24
         action order 1: gact action drop
          random type none pass val 0
          index 3 ref 1 bind 1 installed 10202 sec used 10152 sec
         Action statistics:
         Sent 4200 bytes 50 pkt (dropped 50, overlimits 0 requeues 0)
         backlog 0b 0p requeues 0


Issues:
- tp->q is set by the device used to add the filter. That has to be resolved.
   Impacts the dump (as you can see above)


I think you have more problems if the dump above is reality;->
You added to ingress and this is showing egress.

To complete the thought, dump is:

 tc -s filter show block 22

cheers,
jamal

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