Date: Mon, 1 Feb 2016 19:18:44 +0900 From: Ryota Ozaki <ozak...@netbsd.org>
On Mon, Feb 1, 2016 at 2:41 PM, Ryota Ozaki <ozak...@netbsd.org> wrote: > On Fri, Jan 29, 2016 at 11:58 PM, Taylor R Campbell > <campbell+netbsd-tech-k...@mumble.net> wrote: > So I think it's better to adopt two approaches: > - Add if_percpuq to ifnet and let drivers use it by default (via if_attach) > - Provide a new API that you propose, and let drivers that are ready > for softint use it (we use if_initialize instead) > - Change drivers to use the new API one by one (it would take long time) > - Once we migrate all drivers, then remove if_percpuq from ifnet > (I'm assuming if_percpuq is in ifdef _KERNEL and removable) > > Does this approach satisfy you (or not)? http://www.netbsd.org/~ozaki-r/softint-if_input-percpuq.diff This is a patch that uses if_percpuq. There is no actual user of it yet. I'm trying to apply it to wm. That looks more or less fine. A couple correctness notes: - if_percpu_enqueue: I think you should do splnet, in case some driver might call it at different IPLs -- like bcmeth(4) which may do it from thread context or from softint context. - if_percpuq_purge_ifq: You may need to disestablish the softint before touching remote CPUs' queues; otherwise softints might still be in flight. I would have put creation of the if_percpuq in a separate routine so that you don't have to change callers whose behaviour is not changing; rather you only have to change callers that positively want to use if_percpuq. I might add another field to if_percpuq which is an extra argument to pass, so that the callback function can take both the ifq and an extra argument, as I described in my last message.
