netdev - Re: [PATCH v5 4/6] vhost: Add worker related functions to support kthread

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <foiitmbzkjjjbnz46sfy627jsfwkvya42zujxiigykzj2dluya@iumroiukvfld>
Date: Wed, 8 Jan 2025 15:35:15 +0100
From: Stefano Garzarella <sgarzare@...hat.com>
To: Cindy Lu <lulu@...hat.com>
Cc: jasowang@...hat.com, mst@...hat.com, michael.christie@...cle.com, 
	linux-kernel@...r.kernel.org, virtualization@...ts.linux-foundation.org, 
	netdev@...r.kernel.org
Subject: Re: [PATCH v5 4/6] vhost: Add worker related functions to support
 kthread

On Mon, Dec 30, 2024 at 08:43:51PM +0800, Cindy Lu wrote:
>Restore the previously removed functions kthread_wakeup and
>kthread_stop, and add two new function pointers to wake up and stop
>the workers. The function vhost_worker_create will initialize these
>pointers based on the value of inherit_owner.
>
>The functions vhost_worker_queue() and vhost_worker_destroy() will
>use the function pointer in vhost_worker, which is initialized
>according to the inherit_owner value.
>
>Signed-off-by: Cindy Lu <lulu@...hat.com>
>---
> drivers/vhost/vhost.c | 84 ++++++++++++++++++++++++++++++++++---------
> drivers/vhost/vhost.h |  3 ++
> 2 files changed, 71 insertions(+), 16 deletions(-)
>
>diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
>index 812dfd218bc2..ff17c42e2d1a 100644
>--- a/drivers/vhost/vhost.c
>+++ b/drivers/vhost/vhost.c

[...]

>@@ -736,27 +758,57 @@ static struct vhost_worker *vhost_worker_create(struct vhost_dev *dev)
> 	worker->dev = dev;
> 	snprintf(name, sizeof(name), "vhost-%d", current->pid);
>
>-	vtsk = vhost_task_create(vhost_run_work_list, vhost_worker_killed,
>-				 worker, name);
>-	if (!vtsk)
>-		goto free_worker;
>-
> 	mutex_init(&worker->mutex);
> 	init_llist_head(&worker->work_list);
> 	worker->kcov_handle = kcov_common_handle();
>-	worker->vtsk = vtsk;
>+    /*
>+     * If inherit_owner is true we use vhost_tasks to create
>+     * the worker so all settings/limits like cgroups, NPROC,
>+     * scheduler, etc are inherited from the owner.
>+     * If false,we use kthreads and only attach to the same
>+     * cgroups as the owner for compat with older kernels.
>+     */

This comment block seems to have incorrect indentation, perhaps you need 
to replace the spaces with at least one tab.

>+	if (dev->inherit_owner) {
>+		vtsk = vhost_task_create(vhost_run_work_list,
>+					 vhost_worker_killed, worker, name);
>+		if (!vtsk)
>+			goto free_worker;
>+
>+		worker->vtsk = vtsk;
>+		worker->worker_wakeup = vhost_task_wakeup_fn;
>+		worker->worker_stop = vhost_task_stop_fn;
>+
>+		vhost_task_start(vtsk);
>+		ret = xa_alloc(&dev->worker_xa, &id, worker, xa_limit_32b,
>+			       GFP_KERNEL);
>+		if (ret < 0)
>+			goto stop_worker;
>+	} else {
>+		task = kthread_create(vhost_run_work_kthread_list, worker,
>+				      "vhost-%d", current->pid);
>+		if (IS_ERR(task)) {
>+			ret = PTR_ERR(task);
>+			goto free_worker;
>+		}
>+		worker->kthread_task = task;
>+		worker->worker_wakeup = vhost_kthread_wakeup_fn;
>+		worker->worker_stop = vhost_kthread_stop_fn;
>
>-	vhost_task_start(vtsk);
>+		wake_up_process(task);
>+		ret = xa_alloc(&dev->worker_xa, &id, worker, 
>xa_limit_32b,
>+			       GFP_KERNEL);
>+		if (ret < 0)
>+			goto stop_worker;
>
>-	ret = xa_alloc(&dev->worker_xa, &id, worker, xa_limit_32b, GFP_KERNEL);
>-	if (ret < 0)
>-		goto stop_worker;
>-	worker->id = id;
>+		ret = vhost_attach_task_to_cgroups(worker);
>+		if (ret)
>+			goto stop_worker;
>+	}
>
>+	worker->id = id;
> 	return worker;
>-
> stop_worker:
>-	vhost_task_stop(vtsk);
>+	worker->worker_stop(worker);
> free_worker:
> 	kfree(worker);
> 	return NULL;
>diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h
>index c650c4506c70..63b1da08a2b0 100644
>--- a/drivers/vhost/vhost.h
>+++ b/drivers/vhost/vhost.h
>@@ -27,6 +27,7 @@ struct vhost_work {
> };
>
> struct vhost_worker {
>+	struct task_struct *kthread_task;
> 	struct vhost_task	*vtsk;
> 	struct vhost_dev	*dev;
> 	/* Used to serialize device wide flushing with worker swapping. */
>@@ -36,6 +37,8 @@ struct vhost_worker {
> 	u32			id;
> 	int			attachment_cnt;
> 	bool			killed;
>+	void (*worker_wakeup)(struct vhost_worker *worker);
>+	void (*worker_stop)(struct vhost_worker *worker);
> };
>
> /* Poll a file (eventfd or socket) */
>-- 
>2.45.0
>