[Devel] [PATCH RH9 04/10] drivers/vhost: rework attaching cgroups to be worker aware

[Konstantin Khorenko]

On 16.08.2022 09:44, Andrey Zhadchenko wrote:
> Rework vhost_attach_cgroups to manipulate specified worker.
> Implement vhost_worker_flush as we need to flush specific worker.
> 
> https://jira.sw.ru/browse/PSBM-139414
> Signed-off-by: Andrey Zhadchenko <andrey.zhadchenko at virtuozzo.com>
> ---
>   drivers/vhost/vhost.c | 18 ++++++++++++++----
>   1 file changed, 14 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
> index e05cee622dd5..17891241970b 100644
> --- a/drivers/vhost/vhost.c
> +++ b/drivers/vhost/vhost.c
> @@ -264,6 +264,16 @@ void vhost_work_dev_flush(struct vhost_dev *dev)
>   }
>   EXPORT_SYMBOL_GPL(vhost_work_dev_flush);
>   
> +static void vhost_worker_flush(struct vhost_worker *w)
> +{
> +	struct vhost_flush_struct flush;
> +
> +	init_completion(&flush.wait_event);
> +	vhost_work_init(&flush.work, vhost_flush_work);
> +	vhost_work_queue_at_worker(w, &flush.work);
> +	wait_for_completion(&flush.wait_event);
> +}
> +
>   /* Flush any work that has been scheduled. When calling this, don't hold any
>    * locks that are also used by the callback. */
>   void vhost_poll_flush(struct vhost_poll *poll)
> @@ -569,14 +579,14 @@ static void vhost_attach_cgroups_work(struct vhost_work *work)
>   	s->ret = cgroup_attach_task_all(s->owner, current);
>   }
>   
> -static int vhost_attach_cgroups(struct vhost_dev *dev)
> +static int vhost_worker_attach_cgroups(struct vhost_worker *w)
>   {
>   	struct vhost_attach_cgroups_struct attach;
>   
>   	attach.owner = current;
>   	vhost_work_init(&attach.work, vhost_attach_cgroups_work);
> -	vhost_work_queue(dev, &attach.work);
> -	vhost_work_dev_flush(dev);
> +	vhost_work_queue_at_worker(w, &attach.work);
> +	vhost_worker_flush(w);
>   	return attach.ret;
>   }
>   
> @@ -644,7 +654,7 @@ long vhost_dev_set_owner(struct vhost_dev *dev)
>   		dev->nworkers = 1;
>   		wake_up_process(worker); /* avoid contributing to loadavg */
>   
> -		err = vhost_attach_cgroups(dev);
> +		err = vhost_worker_attach_cgroups(&dev->workers[0]);
>   		if (err)
>   			goto err_cgroup;
>   	}

LGTM