Re: [PATCH 4/4] cgroup: implement task_cgroup_path_from_hierarchy()
Hey, Li. On Mon, Apr 15, 2013 at 11:49:57AM +0800, Li Zefan wrote: > But if id is invalid, idr_find() will return NULL. As long as root is not > NULL, > task_cgroup_from_root() will always return a valid cgroup. I'm hopping across multiple devel branches quickly today and somewhat tipsy. Sorry about the blabber. :) -- tejun -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH 4/4] cgroup: implement task_cgroup_path_from_hierarchy()
On 2013/4/15 11:46, Tejun Heo wrote:
> On Mon, Apr 15, 2013 at 11:43:15AM +0800, Li Zefan wrote:
>>> +int task_cgroup_path_from_hierarchy(struct task_struct *task, int
>>> hierarchy_id,
>>> + char *buf, size_t buflen)
>>> +{
>>> + struct cgroupfs_root *root;
>>> + struct cgroup *cgrp = NULL;
>>> + int ret = -ENOENT;
>>> +
>>> + mutex_lock(_mutex);
>>> +
>>> + root = idr_find(_hierarchy_idr, hierarchy_id);
>>> + if (root) {
>>> + cgrp = task_cgroup_from_root(task, root);
>>
>> task_cgroup_from_root() will never return NULL, and there's a BUG_ON(!res)
>> in it.
>
> @hierarchy_id may come from userland, so we probably should update
> task_cgroup_from_root() to return NULL if the id is invalid. Will add
> a patch.
>
But if id is invalid, idr_find() will return NULL. As long as root is not NULL,
task_cgroup_from_root() will always return a valid cgroup.
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Re: [PATCH 4/4] cgroup: implement task_cgroup_path_from_hierarchy()
On Sun, Apr 14, 2013 at 08:46:13PM -0700, Tejun Heo wrote:
> On Mon, Apr 15, 2013 at 11:43:15AM +0800, Li Zefan wrote:
> > > +int task_cgroup_path_from_hierarchy(struct task_struct *task, int
> > > hierarchy_id,
> > > + char *buf, size_t buflen)
> > > +{
> > > + struct cgroupfs_root *root;
> > > + struct cgroup *cgrp = NULL;
> > > + int ret = -ENOENT;
> > > +
> > > + mutex_lock(_mutex);
> > > +
> > > + root = idr_find(_hierarchy_idr, hierarchy_id);
> > > + if (root) {
> > > + cgrp = task_cgroup_from_root(task, root);
> >
> > task_cgroup_from_root() will never return NULL, and there's a BUG_ON(!res)
> > in it.
>
> @hierarchy_id may come from userland, so we probably should update
> task_cgroup_from_root() to return NULL if the id is invalid. Will add
> a patch.
For some reason, I thought you were talking about hierarchy lookup.
Yeap, task_cgroup_from_root() can't be NULL for a valid hierarchy.
Will drop the if.
--
tejun
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Re: [PATCH 4/4] cgroup: implement task_cgroup_path_from_hierarchy()
On Mon, Apr 15, 2013 at 11:43:15AM +0800, Li Zefan wrote:
> > +int task_cgroup_path_from_hierarchy(struct task_struct *task, int
> > hierarchy_id,
> > + char *buf, size_t buflen)
> > +{
> > + struct cgroupfs_root *root;
> > + struct cgroup *cgrp = NULL;
> > + int ret = -ENOENT;
> > +
> > + mutex_lock(_mutex);
> > +
> > + root = idr_find(_hierarchy_idr, hierarchy_id);
> > + if (root) {
> > + cgrp = task_cgroup_from_root(task, root);
>
> task_cgroup_from_root() will never return NULL, and there's a BUG_ON(!res) in
> it.
@hierarchy_id may come from userland, so we probably should update
task_cgroup_from_root() to return NULL if the id is invalid. Will add
a patch.
Thanks.
--
tejun
--
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Re: [PATCH 4/4] cgroup: implement task_cgroup_path_from_hierarchy()
> +int task_cgroup_path_from_hierarchy(struct task_struct *task, int
> hierarchy_id,
> + char *buf, size_t buflen)
> +{
> + struct cgroupfs_root *root;
> + struct cgroup *cgrp = NULL;
> + int ret = -ENOENT;
> +
> + mutex_lock(_mutex);
> +
> + root = idr_find(_hierarchy_idr, hierarchy_id);
> + if (root) {
> + cgrp = task_cgroup_from_root(task, root);
task_cgroup_from_root() will never return NULL, and there's a BUG_ON(!res) in
it.
> + if (cgrp)
> + ret = cgroup_path(cgrp, buf, buflen);
> + }
> +
> + mutex_unlock(_mutex);
> +
> + return ret;
> +}
> +EXPORT_SYMBOL_GPL(task_cgroup_path_from_hierarchy);
--
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Re: [PATCH 4/4] cgroup: implement task_cgroup_path_from_hierarchy()
On Sun, Apr 14, 2013 at 11:36:59AM -0700, Tejun Heo wrote: > kdbus folks want a sane way to determine the cgroup path that a given > task belongs to on a given hierarchy, which is a reasonble thing to > expect from cgroup core. > > Implement task_cgroup_path_from_hierarchy(). > > Signed-off-by: Tejun Heo > Cc: Kay Sievers > Cc: Greg Kroah-Hartman > Cc: Lennart Poettering > Cc: Daniel Mack Thanks so much for doing this. Acked-by: Greg Kroah-Hartman -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
[PATCH 4/4] cgroup: implement task_cgroup_path_from_hierarchy()
kdbus folks want a sane way to determine the cgroup path that a given
task belongs to on a given hierarchy, which is a reasonble thing to
expect from cgroup core.
Implement task_cgroup_path_from_hierarchy().
Signed-off-by: Tejun Heo
Cc: Kay Sievers
Cc: Greg Kroah-Hartman
Cc: Lennart Poettering
Cc: Daniel Mack
---
include/linux/cgroup.h | 2 ++
kernel/cgroup.c| 33 +
2 files changed, 35 insertions(+)
diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index 17ed818..ee83af2 100644
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -443,6 +443,8 @@ int cgroup_is_removed(const struct cgroup *cgrp);
bool cgroup_is_descendant(struct cgroup *cgrp, struct cgroup *ancestor);
int cgroup_path(const struct cgroup *cgrp, char *buf, int buflen);
+int task_cgroup_path_from_hierarchy(struct task_struct *task, int hierarchy_id,
+ char *buf, size_t buflen);
int cgroup_task_count(const struct cgroup *cgrp);
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 75d85e8..5184fcd 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -1842,6 +1842,39 @@ out:
}
EXPORT_SYMBOL_GPL(cgroup_path);
+/**
+ * task_cgroup_path_from_hierarchy - cgroup path of a task on a hierarchy
+ * @task: target task
+ * @hierarchy_id: the hierarchy to look up @task's cgroup from
+ * @buf: the buffer to write the path into
+ * @buflen: the length of the buffer
+ *
+ * Determine @task's cgroup on the hierarchy specified by @hierarchy_id and
+ * copy its path into @buf. This function grabs cgroup_mutex and shouldn't
+ * be used inside locks used by cgroup controller callbacks.
+ */
+int task_cgroup_path_from_hierarchy(struct task_struct *task, int hierarchy_id,
+ char *buf, size_t buflen)
+{
+ struct cgroupfs_root *root;
+ struct cgroup *cgrp = NULL;
+ int ret = -ENOENT;
+
+ mutex_lock(_mutex);
+
+ root = idr_find(_hierarchy_idr, hierarchy_id);
+ if (root) {
+ cgrp = task_cgroup_from_root(task, root);
+ if (cgrp)
+ ret = cgroup_path(cgrp, buf, buflen);
+ }
+
+ mutex_unlock(_mutex);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(task_cgroup_path_from_hierarchy);
+
/*
* Control Group taskset
*/
--
1.8.1.4
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Re: [PATCH 4/4] cgroup: implement task_cgroup_path_from_hierarchy()
+int task_cgroup_path_from_hierarchy(struct task_struct *task, int
hierarchy_id,
+ char *buf, size_t buflen)
+{
+ struct cgroupfs_root *root;
+ struct cgroup *cgrp = NULL;
+ int ret = -ENOENT;
+
+ mutex_lock(cgroup_mutex);
+
+ root = idr_find(cgroup_hierarchy_idr, hierarchy_id);
+ if (root) {
+ cgrp = task_cgroup_from_root(task, root);
task_cgroup_from_root() will never return NULL, and there's a BUG_ON(!res) in
it.
+ if (cgrp)
+ ret = cgroup_path(cgrp, buf, buflen);
+ }
+
+ mutex_unlock(cgroup_mutex);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(task_cgroup_path_from_hierarchy);
--
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Re: [PATCH 4/4] cgroup: implement task_cgroup_path_from_hierarchy()
On Mon, Apr 15, 2013 at 11:43:15AM +0800, Li Zefan wrote:
+int task_cgroup_path_from_hierarchy(struct task_struct *task, int
hierarchy_id,
+ char *buf, size_t buflen)
+{
+ struct cgroupfs_root *root;
+ struct cgroup *cgrp = NULL;
+ int ret = -ENOENT;
+
+ mutex_lock(cgroup_mutex);
+
+ root = idr_find(cgroup_hierarchy_idr, hierarchy_id);
+ if (root) {
+ cgrp = task_cgroup_from_root(task, root);
task_cgroup_from_root() will never return NULL, and there's a BUG_ON(!res) in
it.
@hierarchy_id may come from userland, so we probably should update
task_cgroup_from_root() to return NULL if the id is invalid. Will add
a patch.
Thanks.
--
tejun
--
To unsubscribe from this list: send the line unsubscribe linux-kernel in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH 4/4] cgroup: implement task_cgroup_path_from_hierarchy()
On Sun, Apr 14, 2013 at 08:46:13PM -0700, Tejun Heo wrote:
On Mon, Apr 15, 2013 at 11:43:15AM +0800, Li Zefan wrote:
+int task_cgroup_path_from_hierarchy(struct task_struct *task, int
hierarchy_id,
+ char *buf, size_t buflen)
+{
+ struct cgroupfs_root *root;
+ struct cgroup *cgrp = NULL;
+ int ret = -ENOENT;
+
+ mutex_lock(cgroup_mutex);
+
+ root = idr_find(cgroup_hierarchy_idr, hierarchy_id);
+ if (root) {
+ cgrp = task_cgroup_from_root(task, root);
task_cgroup_from_root() will never return NULL, and there's a BUG_ON(!res)
in it.
@hierarchy_id may come from userland, so we probably should update
task_cgroup_from_root() to return NULL if the id is invalid. Will add
a patch.
For some reason, I thought you were talking about hierarchy lookup.
Yeap, task_cgroup_from_root() can't be NULL for a valid hierarchy.
Will drop the if.
--
tejun
--
To unsubscribe from this list: send the line unsubscribe linux-kernel in
the body of a message to majord...@vger.kernel.org
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Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH 4/4] cgroup: implement task_cgroup_path_from_hierarchy()
On 2013/4/15 11:46, Tejun Heo wrote:
On Mon, Apr 15, 2013 at 11:43:15AM +0800, Li Zefan wrote:
+int task_cgroup_path_from_hierarchy(struct task_struct *task, int
hierarchy_id,
+ char *buf, size_t buflen)
+{
+ struct cgroupfs_root *root;
+ struct cgroup *cgrp = NULL;
+ int ret = -ENOENT;
+
+ mutex_lock(cgroup_mutex);
+
+ root = idr_find(cgroup_hierarchy_idr, hierarchy_id);
+ if (root) {
+ cgrp = task_cgroup_from_root(task, root);
task_cgroup_from_root() will never return NULL, and there's a BUG_ON(!res)
in it.
@hierarchy_id may come from userland, so we probably should update
task_cgroup_from_root() to return NULL if the id is invalid. Will add
a patch.
But if id is invalid, idr_find() will return NULL. As long as root is not NULL,
task_cgroup_from_root() will always return a valid cgroup.
--
To unsubscribe from this list: send the line unsubscribe linux-kernel in
the body of a message to majord...@vger.kernel.org
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Re: [PATCH 4/4] cgroup: implement task_cgroup_path_from_hierarchy()
Hey, Li. On Mon, Apr 15, 2013 at 11:49:57AM +0800, Li Zefan wrote: But if id is invalid, idr_find() will return NULL. As long as root is not NULL, task_cgroup_from_root() will always return a valid cgroup. I'm hopping across multiple devel branches quickly today and somewhat tipsy. Sorry about the blabber. :) -- tejun -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
[PATCH 4/4] cgroup: implement task_cgroup_path_from_hierarchy()
kdbus folks want a sane way to determine the cgroup path that a given
task belongs to on a given hierarchy, which is a reasonble thing to
expect from cgroup core.
Implement task_cgroup_path_from_hierarchy().
Signed-off-by: Tejun Heo t...@kernel.org
Cc: Kay Sievers k...@vrfy.org
Cc: Greg Kroah-Hartman g...@kroah.com
Cc: Lennart Poettering lenn...@poettering.net
Cc: Daniel Mack dan...@zonque.org
---
include/linux/cgroup.h | 2 ++
kernel/cgroup.c| 33 +
2 files changed, 35 insertions(+)
diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index 17ed818..ee83af2 100644
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -443,6 +443,8 @@ int cgroup_is_removed(const struct cgroup *cgrp);
bool cgroup_is_descendant(struct cgroup *cgrp, struct cgroup *ancestor);
int cgroup_path(const struct cgroup *cgrp, char *buf, int buflen);
+int task_cgroup_path_from_hierarchy(struct task_struct *task, int hierarchy_id,
+ char *buf, size_t buflen);
int cgroup_task_count(const struct cgroup *cgrp);
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 75d85e8..5184fcd 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -1842,6 +1842,39 @@ out:
}
EXPORT_SYMBOL_GPL(cgroup_path);
+/**
+ * task_cgroup_path_from_hierarchy - cgroup path of a task on a hierarchy
+ * @task: target task
+ * @hierarchy_id: the hierarchy to look up @task's cgroup from
+ * @buf: the buffer to write the path into
+ * @buflen: the length of the buffer
+ *
+ * Determine @task's cgroup on the hierarchy specified by @hierarchy_id and
+ * copy its path into @buf. This function grabs cgroup_mutex and shouldn't
+ * be used inside locks used by cgroup controller callbacks.
+ */
+int task_cgroup_path_from_hierarchy(struct task_struct *task, int hierarchy_id,
+ char *buf, size_t buflen)
+{
+ struct cgroupfs_root *root;
+ struct cgroup *cgrp = NULL;
+ int ret = -ENOENT;
+
+ mutex_lock(cgroup_mutex);
+
+ root = idr_find(cgroup_hierarchy_idr, hierarchy_id);
+ if (root) {
+ cgrp = task_cgroup_from_root(task, root);
+ if (cgrp)
+ ret = cgroup_path(cgrp, buf, buflen);
+ }
+
+ mutex_unlock(cgroup_mutex);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(task_cgroup_path_from_hierarchy);
+
/*
* Control Group taskset
*/
--
1.8.1.4
--
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Re: [PATCH 4/4] cgroup: implement task_cgroup_path_from_hierarchy()
On Sun, Apr 14, 2013 at 11:36:59AM -0700, Tejun Heo wrote: kdbus folks want a sane way to determine the cgroup path that a given task belongs to on a given hierarchy, which is a reasonble thing to expect from cgroup core. Implement task_cgroup_path_from_hierarchy(). Signed-off-by: Tejun Heo t...@kernel.org Cc: Kay Sievers k...@vrfy.org Cc: Greg Kroah-Hartman g...@kroah.com Cc: Lennart Poettering lenn...@poettering.net Cc: Daniel Mack dan...@zonque.org Thanks so much for doing this. Acked-by: Greg Kroah-Hartman gre...@linuxfoundation.org -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
