Re: kernel binding of devices + hotplug

[Flavio Leitner <fbl@redhat.com>]

On Sun, Apr 15, 2018 at 01:48:36AM +0000, Stephen Hemminger wrote:
> My vote is to work with udev and not try to replace it.
> 
> Driverctl works well. Just not for bifurcated driver

I second that.  We also have other system configs to care about like
kernel parameters and hugepage configuration which I think follow the
same idea that they are system wide configs and should not be managed
by DPDK itself.

fbl


> 
> On Fri, Apr 13, 2018, 9:31 AM Thomas Monjalon <thomas@monjalon.net> wrote:
> 
> > It's time to think (again) how we bind devices with kernel modules.
> > We need to decide how we want to manage hotplugged devices with DPDK.
> >
> > A bit of history first.
> > There was some code in DPDK for bind/unbind, but it has been removed
> > in DPDK 1.7 - http://dpdk.org/commit/5d8751b83
> > Copy of the commit message (in 2014):
> > "
> >         The bind/unbind operations should not be handled by the eal.
> >         These operations should be either done outside of dpdk or
> >         inside the PMDs themselves as these are their problems.
> > "
> >
> > The question raised at this time (4 years ago) is still under discussion.
> > Should we manage binding inside or outside DPDK?
> > Should it be controlled in the application or in the OS base?
> >
> > As you know, we use dpdk-devbind.py.
> > This tool lacks two major features:
> >         - persistent configuration
> >         - hotplug
> >
> > If we consider that the DPDK applications should be able to apply its own
> > policy to choose the devices to bind, then we need to implement binding
> > in the PMD (with EAL helpers).
> >
> > On the other hand, if we consider that it is the system responsibility,
> > then we could choose systemd/udev and driverctl.
> >
> > The debate is launched!
> >
> > Please find more details in the references below.
> >
> > Announce of driverctl:
> >         http://dpdk.org/ml/archives/dev/2015-December/029500.html
> > Repository of driverctl:
> >         https://gitlab.com/driverctl/driverctl
> >
> > Discussion about binding script and driverctl:
> >         http://dpdk.org/ml/archives/dev/2018-April/095687.html
> >
> > Patch to implement binding in DPDK (for hotplug):
> >         http://dpdk.org/ml/archives/dev/2018-April/095714.html
> >
> > Discussion in the same hotplug series:
> >         http://dpdk.org/ml/archives/dev/2018-April/097058.html
> >
> >
> >
> >

-- 
Flavio