[PATCH v2] cgroup/cpuset: Remove stale text

[PATCH v2] cgroup/cpuset: Remove stale text

[Costa Shulyupin]

Task's cpuset pointer was removed by
commit 8793d854edbc ("Task Control Groups: make cpusets a client of cgroups")

Paragraph "The task_lock() exception ...." was removed by
commit 2df167a300d7 ("cgroups: update comments in cpuset.c")

Remove stale text:

 We also require taking task_lock() when dereferencing a
 task's cpuset pointer. See "The task_lock() exception", at the end of this
 comment.

 Accessing a task's cpuset should be done in accordance with the
 guidelines for accessing subsystem state in kernel/cgroup.c

and reformat.

Co-developed-by: Michal Koutný <mkoutny@suse.com>
Co-developed-by: Waiman Long <longman@redhat.com>
Signed-off-by: Costa Shulyupin <costa.shul@redhat.com>

---
v2: Address comments

---
 kernel/cgroup/cpuset.c | 9 ++-------
 1 file changed, 2 insertions(+), 7 deletions(-)

diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c
index d5d2b4036314..ee62207fee9f 100644
--- a/kernel/cgroup/cpuset.c
+++ b/kernel/cgroup/cpuset.c
@@ -207,10 +207,8 @@ static struct cpuset top_cpuset = {
 
 /*
  * There are two global locks guarding cpuset structures - cpuset_mutex and
- * callback_lock. We also require taking task_lock() when dereferencing a
- * task's cpuset pointer. See "The task_lock() exception", at the end of this
- * comment.  The cpuset code uses only cpuset_mutex. Other kernel subsystems
- * can use cpuset_lock()/cpuset_unlock() to prevent change to cpuset
+ * callback_lock. The cpuset code uses only cpuset_mutex. Other kernel
+ * subsystems can use cpuset_lock()/cpuset_unlock() to prevent change to cpuset
  * structures. Note that cpuset_mutex needs to be a mutex as it is used in
  * paths that rely on priority inheritance (e.g. scheduler - on RT) for
  * correctness.
@@ -239,9 +237,6 @@ static struct cpuset top_cpuset = {
  * The cpuset_common_seq_show() handlers only hold callback_lock across
  * small pieces of code, such as when reading out possibly multi-word
  * cpumasks and nodemasks.
- *
- * Accessing a task's cpuset should be done in accordance with the
- * guidelines for accessing subsystem state in kernel/cgroup.c
  */
 
 static DEFINE_MUTEX(cpuset_mutex);
-- 
2.47.0

Re: [PATCH v2] cgroup/cpuset: Remove stale text

[Waiman Long]

On 12/4/24 6:04 AM, Costa Shulyupin wrote:
> Task's cpuset pointer was removed by
> commit 8793d854edbc ("Task Control Groups: make cpusets a client of cgroups")
>
> Paragraph "The task_lock() exception ...." was removed by
> commit 2df167a300d7 ("cgroups: update comments in cpuset.c")
>
> Remove stale text:
>
>   We also require taking task_lock() when dereferencing a
>   task's cpuset pointer. See "The task_lock() exception", at the end of this
>   comment.
>
>   Accessing a task's cpuset should be done in accordance with the
>   guidelines for accessing subsystem state in kernel/cgroup.c
>
> and reformat.
>
> Co-developed-by: Michal Koutný <mkoutny@suse.com>
> Co-developed-by: Waiman Long <longman@redhat.com>
> Signed-off-by: Costa Shulyupin <costa.shul@redhat.com>
>
> ---
> v2: Address comments
>
> ---
>   kernel/cgroup/cpuset.c | 9 ++-------
>   1 file changed, 2 insertions(+), 7 deletions(-)
>
> diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c
> index d5d2b4036314..ee62207fee9f 100644
> --- a/kernel/cgroup/cpuset.c
> +++ b/kernel/cgroup/cpuset.c
> @@ -207,10 +207,8 @@ static struct cpuset top_cpuset = {
>   
>   /*
>    * There are two global locks guarding cpuset structures - cpuset_mutex and
> - * callback_lock. We also require taking task_lock() when dereferencing a
> - * task's cpuset pointer. See "The task_lock() exception", at the end of this
> - * comment.  The cpuset code uses only cpuset_mutex. Other kernel subsystems
> - * can use cpuset_lock()/cpuset_unlock() to prevent change to cpuset
> + * callback_lock. The cpuset code uses only cpuset_mutex. Other kernel
> + * subsystems can use cpuset_lock()/cpuset_unlock() to prevent change to cpuset
>    * structures. Note that cpuset_mutex needs to be a mutex as it is used in
>    * paths that rely on priority inheritance (e.g. scheduler - on RT) for
>    * correctness.
> @@ -239,9 +237,6 @@ static struct cpuset top_cpuset = {
>    * The cpuset_common_seq_show() handlers only hold callback_lock across
>    * small pieces of code, such as when reading out possibly multi-word
>    * cpumasks and nodemasks.
> - *
> - * Accessing a task's cpuset should be done in accordance with the
> - * guidelines for accessing subsystem state in kernel/cgroup.c
>    */
>   
>   static DEFINE_MUTEX(cpuset_mutex);

LGTM

Acked-by: Waiman Long <longman@redhat.com>

Re: [PATCH v2] cgroup/cpuset: Remove stale text

[Tejun Heo]

On Wed, Dec 04, 2024 at 01:04:41PM +0200, Costa Shulyupin wrote:
> Task's cpuset pointer was removed by
> commit 8793d854edbc ("Task Control Groups: make cpusets a client of cgroups")
> 
> Paragraph "The task_lock() exception ...." was removed by
> commit 2df167a300d7 ("cgroups: update comments in cpuset.c")
> 
> Remove stale text:
> 
>  We also require taking task_lock() when dereferencing a
>  task's cpuset pointer. See "The task_lock() exception", at the end of this
>  comment.
> 
>  Accessing a task's cpuset should be done in accordance with the
>  guidelines for accessing subsystem state in kernel/cgroup.c
> 
> and reformat.
> 
> Co-developed-by: Michal Koutný <mkoutny@suse.com>
> Co-developed-by: Waiman Long <longman@redhat.com>
> Signed-off-by: Costa Shulyupin <costa.shul@redhat.com>

Applied to cgroup/for-6.13-fixes.

Thanks.

-- 
tejun