Re: [RFC Patch 0/7] kernel: Introduce multikernel architecture support

Hillf Danton
2025-09-24T22:43:33Z

On Wed, 24 Sep 2025 10:30:28 -0700 Cong Wang wrote:
>On Tue, Sep 23, 2025 at 6:12 PM Hillf Danton <hdanton@sina.com> wrote:
>> On Mon, 22 Sep 2025 14:55:41 -0700 Cong Wang wrote:
>> > On Sat, Sep 20, 2025 at 6:47 PM Hillf Danton <hdanton@sina.com> wrote:
>> > > On Thu, 18 Sep 2025 15:25:59 -0700 Cong Wang wrote:
>> > > > This patch series introduces multikernel architecture support, enabling
>> > > > multiple independent kernel instances to coexist and communicate on a
>> > > > single physical machine. Each kernel instance can run on dedicated CPU
>> > > > cores while sharing the underlying hardware resources.
>> > > >
>> > > > The multikernel architecture provides several key benefits:
>> > > > - Improved fault isolation between different workloads
>> > > > - Enhanced security through kernel-level separation
>> > > > - Better resource utilization than traditional VM (KVM, Xen etc.)
>> > > > - Potential zero-down kernel update with KHO (Kernel Hand Over)
>> > > >
>> > > Could you illustrate a couple of use cases to help understand your idea?
>> >
>> > Sure, below are a few use cases on my mind:
>> >
>> > 1) With sufficient hardware resources: each kernel gets isolated resources
>> > with real bare metal performance. This applies to all VM/container use cases
>> > today, just with pure better performance: no virtualization, no noisy neighbor.
>> >
>> > More importantly, they can co-exist. In theory, you can run a multiernel with
>> > a VM inside and with a container inside the VM.
>> >
>> If the 6.17 eevdf perfs better than the 6.15 one could, their co-exist wastes
>> bare metal cpu cycles.
>
> I think we should never eliminate the ability of not using multikernel, users
> should have a choice. Apologize if I didn't make this clear.
>
If multikernel is one of features the Thompson and Ritchie Unix offered,
all is fine simply because the linux kernel is never the pill expected
to cure all pains particularly in the user space.

> And even if you only want one kernel, you might still want to use
> zero-downtime upgrade via multikernel. ;-)
>
FYI what I see in Shenzhen 2025 in the car cockpit product environment WRT
multikernel is - hypervisor like QNX supports multi virtual machines
including Android, !Android, linux and !linux, RT and !RT.

Hillf