Re: [PATCH v4 2/8] vhost: Add the vhost_worker to support kthread

Stefano Garzarella
2024-12-10T17:52:48Z

On Wed, Dec 11, 2024 at 12:41:41AM +0800, Cindy Lu wrote:
>Add the previously removed function vhost_worker() back
>to support the kthread and rename it to vhost_run_work_kthread_list.
>
>The old function vhost_worker was change to support task in

s/change/changed

>commit 6e890c5d5021 ("vhost: use vhost_tasks for worker threads")
>change to xarray in

"and to support multiple workers per device using xarray in"

>commit 1cdaafa1b8b4 ("vhost: replace single worker pointer with xarray")
>
>Signed-off-by: Cindy Lu <lulu@redhat.com>
>---
> drivers/vhost/vhost.c | 38 ++++++++++++++++++++++++++++++++++++++
> 1 file changed, 38 insertions(+)
>
>diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
>index eaddbd39c29b..1feba29abf95 100644
>--- a/drivers/vhost/vhost.c
>+++ b/drivers/vhost/vhost.c
>@@ -388,6 +388,44 @@ static void vhost_vq_reset(struct vhost_dev *dev,
> __vhost_vq_meta_reset(vq);
> }
>
>+static int vhost_run_work_kthread_list(void *data)
>+{
>+ struct vhost_worker *worker = data;
>+ struct vhost_work *work, *work_next;
>+ struct vhost_dev *dev = worker->dev;
>+ struct llist_node *node;
>+
>+ kthread_use_mm(dev->mm);
>+
>+ for (;;) {
>+ /* mb paired w/ kthread_stop */
>+ set_current_state(TASK_INTERRUPTIBLE);
>+
>+ if (kthread_should_stop()) {
>+ __set_current_state(TASK_RUNNING);
>+ break;
>+ }
>+ node = llist_del_all(&worker->work_list);
>+ if (!node)
>+ schedule();
>+
>+ node = llist_reverse_order(node);
>+ /* make sure flag is seen after deletion */
>+ smp_wmb();
>+ llist_for_each_entry_safe(work, work_next, node, node) {
>+ clear_bit(VHOST_WORK_QUEUED, &work->flags);
>+ __set_current_state(TASK_RUNNING);
>+ kcov_remote_start_common(worker->kcov_handle);
>+ work->fn(work);
>+ kcov_remote_stop();
>+ cond_resched();
>+ }
>+ }
>+ kthread_unuse_mm(dev->mm);
>+
>+ return 0;
>+}
>+
> static bool vhost_run_work_list(void *data)
> {
> struct vhost_worker *worker = data;
>--
>2.45.0
>