[v4] vhost: Add support of kthread API

[PATCH v4 3/8] vhost: Add the cgroup related function

Posted by Cindy Lu 1 year ago

Add back the previously removed cgroup function to support the kthread
The biggest change for this part is in vhost_attach_cgroups() and
vhost_attach_task_to_cgroups().

The old function was remove in
commit 6e890c5d5021 ("vhost: use vhost_tasks for worker threads")

Signed-off-by: Cindy Lu <lulu@redhat.com>
---
 drivers/vhost/vhost.c | 33 +++++++++++++++++++++++++++++++++
 1 file changed, 33 insertions(+)

diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index 1feba29abf95..812dfd218bc2 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -22,6 +22,7 @@
 #include <linux/slab.h>
 #include <linux/vmalloc.h>
 #include <linux/kthread.h>
+#include <linux/cgroup.h>
 #include <linux/module.h>
 #include <linux/sort.h>
 #include <linux/sched/mm.h>
@@ -620,6 +621,38 @@ long vhost_dev_check_owner(struct vhost_dev *dev)
 }
 EXPORT_SYMBOL_GPL(vhost_dev_check_owner);
 
+struct vhost_attach_cgroups_struct {
+	struct vhost_work work;
+	struct task_struct *owner;
+	int ret;
+};
+
+static void vhost_attach_cgroups_work(struct vhost_work *work)
+{
+	struct vhost_attach_cgroups_struct *s;
+
+	s = container_of(work, struct vhost_attach_cgroups_struct, work);
+	s->ret = cgroup_attach_task_all(s->owner, current);
+}
+
+static int vhost_attach_task_to_cgroups(struct vhost_worker *worker)
+{
+	struct vhost_flush_struct flush;
+	struct vhost_attach_cgroups_struct attach;
+
+	attach.owner = current;
+
+	vhost_work_init(&attach.work, vhost_attach_cgroups_work);
+	vhost_worker_queue(worker, &attach.work);
+
+	init_completion(&flush.wait_event);
+	vhost_work_init(&flush.work, vhost_flush_work);
+	vhost_worker_queue(worker, &flush.work);
+	wait_for_completion(&flush.wait_event);
+
+	return attach.ret;
+}
+
 /* Caller should have device mutex */
 bool vhost_dev_has_owner(struct vhost_dev *dev)
 {
-- 
2.45.0

Re: [PATCH v4 3/8] vhost: Add the cgroup related function

Posted by Stefano Garzarella 1 year ago

On Wed, Dec 11, 2024 at 12:41:42AM +0800, Cindy Lu wrote:
>Add back the previously removed cgroup function to support the kthread

nit: missing . at the end

>The biggest change for this part is in vhost_attach_cgroups() and
>vhost_attach_task_to_cgroups().

It's not clear what the big change is, is there a piece missing?

>
>The old function was remove in

s/remove/removed

BTW which is the old function?

>commit 6e890c5d5021 ("vhost: use vhost_tasks for worker threads")
>
>Signed-off-by: Cindy Lu <lulu@redhat.com>
>---
> drivers/vhost/vhost.c | 33 +++++++++++++++++++++++++++++++++
> 1 file changed, 33 insertions(+)
>
>diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
>index 1feba29abf95..812dfd218bc2 100644
>--- a/drivers/vhost/vhost.c
>+++ b/drivers/vhost/vhost.c
>@@ -22,6 +22,7 @@
> #include <linux/slab.h>
> #include <linux/vmalloc.h>
> #include <linux/kthread.h>
>+#include <linux/cgroup.h>
> #include <linux/module.h>
> #include <linux/sort.h>
> #include <linux/sched/mm.h>
>@@ -620,6 +621,38 @@ long vhost_dev_check_owner(struct vhost_dev *dev)
> }
> EXPORT_SYMBOL_GPL(vhost_dev_check_owner);
>
>+struct vhost_attach_cgroups_struct {
>+	struct vhost_work work;
>+	struct task_struct *owner;
>+	int ret;
>+};
>+
>+static void vhost_attach_cgroups_work(struct vhost_work *work)
>+{
>+	struct vhost_attach_cgroups_struct *s;
>+
>+	s = container_of(work, struct vhost_attach_cgroups_struct, work);
>+	s->ret = cgroup_attach_task_all(s->owner, current);
>+}
>+
>+static int vhost_attach_task_to_cgroups(struct vhost_worker *worker)

This function looks renamed, should we mention in the commit 
description?

>+{
>+	struct vhost_flush_struct flush;
>+	struct vhost_attach_cgroups_struct attach;
>+
>+	attach.owner = current;
>+
>+	vhost_work_init(&attach.work, vhost_attach_cgroups_work);
>+	vhost_worker_queue(worker, &attach.work);
>+
>+	init_completion(&flush.wait_event);
>+	vhost_work_init(&flush.work, vhost_flush_work);
>+	vhost_worker_queue(worker, &flush.work);
>+	wait_for_completion(&flush.wait_event);

IIUC this block is the old "vhost_dev_flush", right?

Maybe we should mention also that in the commit description.

>+
>+	return attach.ret;
>+}
>+
> /* Caller should have device mutex */
> bool vhost_dev_has_owner(struct vhost_dev *dev)
> {
>-- 
>2.45.0
>

Re: [PATCH v4 3/8] vhost: Add the cgroup related function

Posted by Cindy Lu 12 months ago

On Wed, Dec 11, 2024 at 1:53 AM Stefano Garzarella <sgarzare@redhat.com> wrote:
>
> On Wed, Dec 11, 2024 at 12:41:42AM +0800, Cindy Lu wrote:
> >Add back the previously removed cgroup function to support the kthread
>
> nit: missing . at the end
>
will fix this
> >The biggest change for this part is in vhost_attach_cgroups() and
> >vhost_attach_task_to_cgroups().
>
> It's not clear what the big change is, is there a piece missing?
>
sure, I will rewrite this part to make it more clear
Thanks
cindy
> >
> >The old function was remove in
>
> s/remove/removed
>
> BTW which is the old function?
>
I will add this information
Thanks
cindy
> >commit 6e890c5d5021 ("vhost: use vhost_tasks for worker threads")
> >
> >Signed-off-by: Cindy Lu <lulu@redhat.com>
> >---
> > drivers/vhost/vhost.c | 33 +++++++++++++++++++++++++++++++++
> > 1 file changed, 33 insertions(+)
> >
> >diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
> >index 1feba29abf95..812dfd218bc2 100644
> >--- a/drivers/vhost/vhost.c
> >+++ b/drivers/vhost/vhost.c
> >@@ -22,6 +22,7 @@
> > #include <linux/slab.h>
> > #include <linux/vmalloc.h>
> > #include <linux/kthread.h>
> >+#include <linux/cgroup.h>
> > #include <linux/module.h>
> > #include <linux/sort.h>
> > #include <linux/sched/mm.h>
> >@@ -620,6 +621,38 @@ long vhost_dev_check_owner(struct vhost_dev *dev)
> > }
> > EXPORT_SYMBOL_GPL(vhost_dev_check_owner);
> >
> >+struct vhost_attach_cgroups_struct {
> >+      struct vhost_work work;
> >+      struct task_struct *owner;
> >+      int ret;
> >+};
> >+
> >+static void vhost_attach_cgroups_work(struct vhost_work *work)
> >+{
> >+      struct vhost_attach_cgroups_struct *s;
> >+
> >+      s = container_of(work, struct vhost_attach_cgroups_struct, work);
> >+      s->ret = cgroup_attach_task_all(s->owner, current);
> >+}
> >+
> >+static int vhost_attach_task_to_cgroups(struct vhost_worker *worker)
>
> This function looks renamed, should we mention in the commit
> description?
>
> >+{
> >+      struct vhost_flush_struct flush;
> >+      struct vhost_attach_cgroups_struct attach;
> >+
> >+      attach.owner = current;
> >+
> >+      vhost_work_init(&attach.work, vhost_attach_cgroups_work);
> >+      vhost_worker_queue(worker, &attach.work);
> >+
> >+      init_completion(&flush.wait_event);
> >+      vhost_work_init(&flush.work, vhost_flush_work);
> >+      vhost_worker_queue(worker, &flush.work);
> >+      wait_for_completion(&flush.wait_event);
>
> IIUC this block is the old "vhost_dev_flush", right?
>
> Maybe we should mention also that in the commit description.
>
sure, will add these informations
Thanks
cindy
> >+
> >+      return attach.ret;
> >+}
> >+
> > /* Caller should have device mutex */
> > bool vhost_dev_has_owner(struct vhost_dev *dev)
> > {
> >--
> >2.45.0
> >
>