On Mon, Jul 14, 2025 at 3:13 PM Cindy Lu <lulu@xxxxxxxxxx> wrote:
>
> This patch reintroduces kthread mode for vhost workers and provides
> configuration to select between kthread and task worker.
>
> - Add 'fork_owner' parameter to vhost_dev to let users select kthread
> or task mode. Default mode is task mode(VHOST_FORK_OWNER_TASK).
>
> - Reintroduce kthread mode support:
> * Bring back the original vhost_worker() implementation,
> and renamed to vhost_run_work_kthread_list().
> * Add cgroup support for the kthread
> * Introduce struct vhost_worker_ops:
> - Encapsulates create / stop / wake‑up callbacks.
> - vhost_worker_create() selects the proper ops according to
> inherit_owner.
>
> - Userspace configuration interface:
> * New IOCTLs:
> - VHOST_SET_FORK_FROM_OWNER lets userspace select task mode
> (VHOST_FORK_OWNER_TASK) or kthread mode (VHOST_FORK_OWNER_KTHREAD)
> - VHOST_GET_FORK_FROM_OWNER reads the current worker mode
> * Expose module parameter 'fork_from_owner_default' to allow system
> administrators to configure the default mode for vhost workers
> * Kconfig option CONFIG_VHOST_ENABLE_FORK_OWNER_CONTROL controls whether
> these IOCTLs and the parameter are available
>
> - The VHOST_NEW_WORKER functionality requires fork_owner to be set
> to true, with validation added to ensure proper configuration
>
> This partially reverts or improves upon:
> commit 6e890c5d5021 ("vhost: use vhost_tasks for worker threads")
> commit 1cdaafa1b8b4 ("vhost: replace single worker pointer with xarray")
>
> Signed-off-by: Cindy Lu <lulu@xxxxxxxxxx>
> ---
Acked-by: Jason Wang <jasowang@xxxxxxxxxx>
Thanks
