[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [PATCH 2/8] xen/evtchn: modify evtchn_alloc_unbound to allocate specified port
Hi Rahul,
On 20/07/2022 10:59, Rahul Singh wrote:
On 13 Jul 2022, at 1:29 pm, Julien Grall <julien@xxxxxxx> wrote:
On 13/07/2022 13:12, Bertrand Marquis wrote:
On 13 Jul 2022, at 12:31, Julien Grall <julien@xxxxxxx> wrote:
I can't
see why it would be wrong to have a more tight limit on static ports
than on traditional ("dynamic") ones. Even if only to make sure so
many dynamic ones are left.
This is similar to Xen forbidding to close a static port: it is not the
hypervisor business to check that there are enough event channel ports freed
for dynamic allocation.
On other side we need to be cautious not to add too much complexity in the code
by trying to make things always magically work.
If you want Xen to be accessible to non expert by magically working all the
time, there would be a lot of work to do.
It is not clear to me whether you are referring to a developper or admin here.
On the admin side, we need to make sure they have an easy way to configure
event channels. One knob is always going to easier than two knobs.
On the developper side, this could be resolved by better documentation in the
code/interface.
Cheers,
To conclude the discussion, If everyone agree I will add the below patch or
similar in the next version to restrict the
max number of evtchn supported as suggested.
I am fine if the limit for domU is fixed by Xen for now. However, for
dom0, 4096 is potentially too low if you have many PV drivers (each
backend will need a few event channels). So I don't think this wants to
be fixed by Xen.
I am not entirely sure we want to limit the number of event channels for
dom0. But if you want to, then this will have to be done via a command
line option (or device-tree property).
Cheers,
--
Julien Grall
|
