On Mon, Aug 19, 2024 at 5:29 PM Cindy Lu [off-list ref] 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(-)

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2.45.0