Re: [RFC 0/7] vhost: Add support of kthread API

[Jason Wang]

On Mon, Aug 19, 2024 at 5:29 PM Cindy Lu <lulu@xxxxxxxxxx> wrote:
>
> In commit 6e890c5d5021 ("vhost: use vhost_tasks for worker threads"),
> vhost removed the support for the kthread API. However, there are
> still situations where there is a request to use kthread.

I think we need some tweak here. For example, we need to mention that
the introduction of the vhost_taks introduce userspace noticeable
changes as the worker inherit attributes from the owner instead of the
kthreadd etc.

> In this RFC, the support of kthread is added back. Additionally,
> a module_param is added to identify which mode we are using,

It's probably not identified, it's more about if we need to "enforce"
the old behaviour.

> and
> a new UAPI is introduced to allow the userspace app to set the
> mode they want to use.
>
> Cindy Lu (7):
>   vhost: Add a new module_param for enable kthread
>   vhost: Add kthread support in function vhost_worker_queue()
>   vhost: Add kthread support in function vhost_workers_free()
>   vhost: Add the vhost_worker to support kthread
>   vhost: Add the cgroup related function
>   vhost: Add kthread support in function vhost_worker_create
>   vhost: Add new UAPI to support changing Kthread mode
>
>  drivers/vhost/vhost.c      | 241 +++++++++++++++++++++++++++++++++++--
>  drivers/vhost/vhost.h      |   1 +
>  include/uapi/linux/vhost.h |   2 +
>  3 files changed, 235 insertions(+), 9 deletions(-)
>
> --
> 2.45.0
>