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[PATCH -next 2/3] cgroup/cpuset: remove fetch_xcpus

Chen Ridong posted 3 patches 1 year, 5 months ago
There is a newer version of this series
[PATCH -next 2/3] cgroup/cpuset: remove fetch_xcpus
Posted by Chen Ridong 1 year, 5 months ago 
Both fetch_xcpus and user_xcpus functions are used to retrieve the value
of exclusive_cpus. If exclusive_cpus is not set, cpus_allowed is the
implicit value used as exclusive in a local partition. I can not imagine
a scenario where effective_xcpus is not empty when exclusive_cpus is
empty. Therefore, I suggest removing the fetch_xcpus function.

Signed-off-by: Chen Ridong <chenridong@huawei.com>
---
 kernel/cgroup/cpuset.c | 13 +++----------
 1 file changed, 3 insertions(+), 10 deletions(-)

diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c
index fdd5346616d3..8be0259065f5 100644
--- a/kernel/cgroup/cpuset.c
+++ b/kernel/cgroup/cpuset.c
@@ -771,13 +771,6 @@ static inline bool xcpus_empty(struct cpuset *cs)
 	       cpumask_empty(cs->exclusive_cpus);
 }
 
-static inline struct cpumask *fetch_xcpus(struct cpuset *cs)
-{
-	return !cpumask_empty(cs->exclusive_cpus) ? cs->exclusive_cpus :
-	       cpumask_empty(cs->effective_xcpus) ? cs->cpus_allowed
-						  : cs->effective_xcpus;
-}
-
 /*
  * cpusets_are_exclusive() - check if two cpusets are exclusive
  *
@@ -785,8 +778,8 @@ static inline struct cpumask *fetch_xcpus(struct cpuset *cs)
  */
 static inline bool cpusets_are_exclusive(struct cpuset *cs1, struct cpuset *cs2)
 {
-	struct cpumask *xcpus1 = fetch_xcpus(cs1);
-	struct cpumask *xcpus2 = fetch_xcpus(cs2);
+	struct cpumask *xcpus1 = user_xcpus(cs1);
+	struct cpumask *xcpus2 = user_xcpus(cs2);
 
 	if (cpumask_intersects(xcpus1, xcpus2))
 		return false;
@@ -2585,7 +2578,7 @@ static int update_cpumask(struct cpuset *cs, struct cpuset *trialcs,
 		invalidate = true;
 		rcu_read_lock();
 		cpuset_for_each_child(cp, css, parent) {
-			struct cpumask *xcpus = fetch_xcpus(trialcs);
+			struct cpumask *xcpus = user_xcpus(trialcs);
 
 			if (is_partition_valid(cp) &&
 			    cpumask_intersects(xcpus, cp->effective_xcpus)) {
-- 
2.34.1
Re: [PATCH -next 2/3] cgroup/cpuset: remove fetch_xcpus
Posted by Waiman Long 1 year, 5 months ago 
On 8/16/24 04:27, Chen Ridong wrote:
> Both fetch_xcpus and user_xcpus functions are used to retrieve the value
> of exclusive_cpus. If exclusive_cpus is not set, cpus_allowed is the
> implicit value used as exclusive in a local partition. I can not imagine
> a scenario where effective_xcpus is not empty when exclusive_cpus is
> empty. Therefore, I suggest removing the fetch_xcpus function.
>
> Signed-off-by: Chen Ridong <chenridong@huawei.com>
> ---
>   kernel/cgroup/cpuset.c | 13 +++----------
>   1 file changed, 3 insertions(+), 10 deletions(-)
>
> diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c
> index fdd5346616d3..8be0259065f5 100644
> --- a/kernel/cgroup/cpuset.c
> +++ b/kernel/cgroup/cpuset.c
> @@ -771,13 +771,6 @@ static inline bool xcpus_empty(struct cpuset *cs)
>   	       cpumask_empty(cs->exclusive_cpus);
>   }
>   
> -static inline struct cpumask *fetch_xcpus(struct cpuset *cs)
> -{
> -	return !cpumask_empty(cs->exclusive_cpus) ? cs->exclusive_cpus :
> -	       cpumask_empty(cs->effective_xcpus) ? cs->cpus_allowed
> -						  : cs->effective_xcpus;
> -}
> -
>   /*
>    * cpusets_are_exclusive() - check if two cpusets are exclusive
>    *
> @@ -785,8 +778,8 @@ static inline struct cpumask *fetch_xcpus(struct cpuset *cs)
>    */
>   static inline bool cpusets_are_exclusive(struct cpuset *cs1, struct cpuset *cs2)
>   {
> -	struct cpumask *xcpus1 = fetch_xcpus(cs1);
> -	struct cpumask *xcpus2 = fetch_xcpus(cs2);
> +	struct cpumask *xcpus1 = user_xcpus(cs1);
> +	struct cpumask *xcpus2 = user_xcpus(cs2);
>   
>   	if (cpumask_intersects(xcpus1, xcpus2))
>   		return false;
> @@ -2585,7 +2578,7 @@ static int update_cpumask(struct cpuset *cs, struct cpuset *trialcs,
>   		invalidate = true;
>   		rcu_read_lock();
>   		cpuset_for_each_child(cp, css, parent) {
> -			struct cpumask *xcpus = fetch_xcpus(trialcs);
> +			struct cpumask *xcpus = user_xcpus(trialcs);
>   
>   			if (is_partition_valid(cp) &&
>   			    cpumask_intersects(xcpus, cp->effective_xcpus)) {

LGTM.

Reviewed-by: Waiman Long <longman@redhat.com>
Re: [PATCH -next 2/3] cgroup/cpuset: remove fetch_xcpus
Posted by Saket Kumar Bhaskar 1 year, 5 months ago 
On Fri, Aug 16, 2024 at 08:27:26AM +0000, Chen Ridong wrote:
> Both fetch_xcpus and user_xcpus functions are used to retrieve the value
> of exclusive_cpus. If exclusive_cpus is not set, cpus_allowed is the
> implicit value used as exclusive in a local partition. I can not imagine
> a scenario where effective_xcpus is not empty when exclusive_cpus is
> empty. Therefore, I suggest removing the fetch_xcpus function.
> 
> Signed-off-by: Chen Ridong <chenridong@huawei.com>
> ---
>  kernel/cgroup/cpuset.c | 13 +++----------
>  1 file changed, 3 insertions(+), 10 deletions(-)
> 
> diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c
> index fdd5346616d3..8be0259065f5 100644
> --- a/kernel/cgroup/cpuset.c
> +++ b/kernel/cgroup/cpuset.c
> @@ -771,13 +771,6 @@ static inline bool xcpus_empty(struct cpuset *cs)
>  	       cpumask_empty(cs->exclusive_cpus);
>  }
>  
> -static inline struct cpumask *fetch_xcpus(struct cpuset *cs)
> -{
> -	return !cpumask_empty(cs->exclusive_cpus) ? cs->exclusive_cpus :
> -	       cpumask_empty(cs->effective_xcpus) ? cs->cpus_allowed
> -						  : cs->effective_xcpus;
> -}
> -
>  /*
>   * cpusets_are_exclusive() - check if two cpusets are exclusive
>   *
> @@ -785,8 +778,8 @@ static inline struct cpumask *fetch_xcpus(struct cpuset *cs)
>   */
>  static inline bool cpusets_are_exclusive(struct cpuset *cs1, struct cpuset *cs2)
>  {
> -	struct cpumask *xcpus1 = fetch_xcpus(cs1);
> -	struct cpumask *xcpus2 = fetch_xcpus(cs2);
> +	struct cpumask *xcpus1 = user_xcpus(cs1);
> +	struct cpumask *xcpus2 = user_xcpus(cs2);
>  
>  	if (cpumask_intersects(xcpus1, xcpus2))
>  		return false;
> @@ -2585,7 +2578,7 @@ static int update_cpumask(struct cpuset *cs, struct cpuset *trialcs,
>  		invalidate = true;
>  		rcu_read_lock();
>  		cpuset_for_each_child(cp, css, parent) {
> -			struct cpumask *xcpus = fetch_xcpus(trialcs);
> +			struct cpumask *xcpus = user_xcpus(trialcs);
>  
>  			if (is_partition_valid(cp) &&
>  			    cpumask_intersects(xcpus, cp->effective_xcpus)) {
> -- 
> 2.34.1
> 

Hi,

In update_cpumask too fetch_xcpus is used. You may want to remove it from there too.

diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c
index 40ec4abaf440..1b4ee6403de6 100644
--- a/kernel/cgroup/cpuset.c
+++ b/kernel/cgroup/cpuset.c
@@ -2587,7 +2587,7 @@ static int update_cpumask(struct cpuset *cs, struct cpuset *trialcs,
                invalidate = true;
                rcu_read_lock();
                cpuset_for_each_child(cp, css, parent) {
-                       struct cpumask *xcpus = fetch_xcpus(trialcs);
+                       struct cpumask *xcpus = user_xcpus(trialcs);

                        if (is_partition_valid(cp) &&
                            cpumask_intersects(xcpus, cp->effective_xcpus)) {


Reviewed-by: Saket Kumar Bhaskar <skb99@linux.ibm.com> 

Thanks,
Saket

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