Mon, Sep 19, 2016 at 04:59:22PM CEST, ro...@cumulusnetworks.com wrote: >On 9/18/16, 11:14 PM, Jiri Pirko wrote: >> Mon, Sep 19, 2016 at 01:16:17AM CEST, ro...@cumulusnetworks.com wrote: >>> On 9/18/16, 1:00 PM, Florian Fainelli wrote: >>>> Le 06/09/2016 à 05:01, Jiri Pirko a écrit : >>>>> From: Jiri Pirko <j...@mellanox.com> >>>>> >>>>> This is RFC, unfinished. I came across some issues in the process so I >>>>> would >>>>> like to share those and restart the fib offload discussion in order to >>>>> make it >>>>> really usable. >>>>> >>>>> So the goal of this patchset is to allow driver to propagate all prefixes >>>>> configured in kernel down HW. This is necessary for routing to work >>>>> as expected. If we don't do that HW might forward prefixes known to kernel >>>>> incorrectly. Take an example when default route is set in switch HW and >>>>> there >>>>> is an IP address set on a management (non-switch) port. >>>>> >>>>> Currently, only fibs related to the switch port netdev are offloaded using >>>>> switchdev ops. This model is not extendable so the first patch introduces >>>>> a replacement: notifier to propagate fib additions and removals to whoever >>>>> interested. The second patch makes mlxsw to adopt this new way, >>>>> registering >>>>> one notifier block for each mlxsw (asic) instance. >>>> Instead of introducing another specialization of a notifier_block >>>> implementation, could we somehow have a kernel-based netlink listener >>>> which receives the same kind of event information from rtmsg_fib()? >>>> >>>> The reason is that having such a facility would hook directly onto >>>> existing rtmsg_* calls that exist throughout the stack, and that seems >>>> to scale better. >>> I was thinking along the same lines. Instead of proliferating notifier >>> blocks >>> through-out the stack for switchdev offload, putting existing events to use >>> would be nice. >>> >>> But the problem though is drivers having to parse the netlink msg again. >>> also, the intent >>> here is to do the offload first ..before the route is added to the kernel >>> (though i don't see that in >>> the current series). existing netlink rmsg_fib events are generated after >>> the route is added to the kernel. >>> >>> >>> Jiri, instead of the notifier, do you see a problem with always calling the >>> existing switchdev >>> offload api for every route for every asic instance ?. the first device >>> where the route fits wins. >> There is not list of asic instances. Therefore the notifier fits much better >> here. >> >> >> >>> it seems similar to driver registering for notifier and looking at every >>> route ... >>> am i missing something ? >>> and the policies you mention could help around selecting the asic instance >>> (FCFS or mirror). >>> you will need to abstract out the asic instance for switchdev api to call >>> on, but I thought you >>> already have that in some form in your devlink infrastructure. >> switchdev asic instances and devlink instances are orthogonal. > >maybe it is not today...but the requirement for devlink was to provide a way >to communicate >to the switch driver >- global switch attributes or >- things that cannot go via switch ports (exactly the problem you are trying >to solve for routes here)
Devlink is a general beast, not switch specific one. I see no need to use fib->devlink->driver route inside kernel. Devlink is for userspace facing. > >so, maybe an instance of switch asic modeled via devlink will help here and >possibly all/other switchdev >offload hooks ? Maybe, but in case of fibs, the notifier just fits great. I see no need for anything else.
