The set of cpuset isolated CPUs is now included in HK_TYPE_DOMAIN
housekeeping cpumask. There is no usecase left interested in just
checking what is isolated by cpuset and not by the isolcpus= kernel
boot parameter.

Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
---
 include/linux/cpuset.h          |  6 ------
 include/linux/sched/isolation.h |  3 +--
 kernel/cgroup/cpuset.c          | 12 ------------
 3 files changed, 1 insertion(+), 20 deletions(-)

diff --git a/include/linux/cpuset.h b/include/linux/cpuset.h
index 051d36fec578..a10775a4f702 100644
--- a/include/linux/cpuset.h
+++ b/include/linux/cpuset.h
@@ -78,7 +78,6 @@ extern void cpuset_lock(void);
 extern void cpuset_unlock(void);
 extern void cpuset_cpus_allowed(struct task_struct *p, struct cpumask *mask);
 extern bool cpuset_cpus_allowed_fallback(struct task_struct *p);
-extern bool cpuset_cpu_is_isolated(int cpu);
 extern nodemask_t cpuset_mems_allowed(struct task_struct *p);
 #define cpuset_current_mems_allowed (current->mems_allowed)
 void cpuset_init_current_mems_allowed(void);
@@ -208,11 +207,6 @@ static inline bool cpuset_cpus_allowed_fallback(struct task_struct *p)
 	return false;
 }
 
-static inline bool cpuset_cpu_is_isolated(int cpu)
-{
-	return false;
-}
-
 static inline nodemask_t cpuset_mems_allowed(struct task_struct *p)
 {
 	return node_possible_map;
diff --git a/include/linux/sched/isolation.h b/include/linux/sched/isolation.h
index 94d5c835121b..0f50c152cf68 100644
--- a/include/linux/sched/isolation.h
+++ b/include/linux/sched/isolation.h
@@ -76,8 +76,7 @@ static inline bool housekeeping_cpu(int cpu, enum hk_type type)
 static inline bool cpu_is_isolated(int cpu)
 {
 	return !housekeeping_test_cpu(cpu, HK_TYPE_DOMAIN) ||
-	       !housekeeping_test_cpu(cpu, HK_TYPE_TICK) ||
-	       cpuset_cpu_is_isolated(cpu);
+	       !housekeeping_test_cpu(cpu, HK_TYPE_TICK);
 }
 
 #endif /* _LINUX_SCHED_ISOLATION_H */
diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c
index ea102e4695a5..e19d3375a4ec 100644
--- a/kernel/cgroup/cpuset.c
+++ b/kernel/cgroup/cpuset.c
@@ -29,7 +29,6 @@
 #include <linux/mempolicy.h>
 #include <linux/mm.h>
 #include <linux/memory.h>
-#include <linux/export.h>
 #include <linux/rcupdate.h>
 #include <linux/sched.h>
 #include <linux/sched/deadline.h>
@@ -1405,17 +1404,6 @@ static void update_housekeeping_cpumask(bool isolcpus_updated)
 	WARN_ON_ONCE(ret < 0);
 }
 
-/**
- * cpuset_cpu_is_isolated - Check if the given CPU is isolated
- * @cpu: the CPU number to be checked
- * Return: true if CPU is used in an isolated partition, false otherwise
- */
-bool cpuset_cpu_is_isolated(int cpu)
-{
-	return cpumask_test_cpu(cpu, isolated_cpus);
-}
-EXPORT_SYMBOL_GPL(cpuset_cpu_is_isolated);
-
 /**
  * rm_siblings_excl_cpus - Remove exclusive CPUs that are used by sibling cpusets
  * @parent: Parent cpuset containing all siblings
-- 
2.51.0

On 10/13/25 4:31 PM, Frederic Weisbecker wrote:
> The set of cpuset isolated CPUs is now included in HK_TYPE_DOMAIN
> housekeeping cpumask. There is no usecase left interested in just
> checking what is isolated by cpuset and not by the isolcpus= kernel
> boot parameter.
>
> Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
> ---
>   include/linux/cpuset.h          |  6 ------
>   include/linux/sched/isolation.h |  3 +--
>   kernel/cgroup/cpuset.c          | 12 ------------
>   3 files changed, 1 insertion(+), 20 deletions(-)
>
> diff --git a/include/linux/cpuset.h b/include/linux/cpuset.h
> index 051d36fec578..a10775a4f702 100644
> --- a/include/linux/cpuset.h
> +++ b/include/linux/cpuset.h
> @@ -78,7 +78,6 @@ extern void cpuset_lock(void);
>   extern void cpuset_unlock(void);
>   extern void cpuset_cpus_allowed(struct task_struct *p, struct cpumask *mask);
>   extern bool cpuset_cpus_allowed_fallback(struct task_struct *p);
> -extern bool cpuset_cpu_is_isolated(int cpu);
>   extern nodemask_t cpuset_mems_allowed(struct task_struct *p);
>   #define cpuset_current_mems_allowed (current->mems_allowed)
>   void cpuset_init_current_mems_allowed(void);
> @@ -208,11 +207,6 @@ static inline bool cpuset_cpus_allowed_fallback(struct task_struct *p)
>   	return false;
>   }
>   
> -static inline bool cpuset_cpu_is_isolated(int cpu)
> -{
> -	return false;
> -}
> -
>   static inline nodemask_t cpuset_mems_allowed(struct task_struct *p)
>   {
>   	return node_possible_map;
> diff --git a/include/linux/sched/isolation.h b/include/linux/sched/isolation.h
> index 94d5c835121b..0f50c152cf68 100644
> --- a/include/linux/sched/isolation.h
> +++ b/include/linux/sched/isolation.h
> @@ -76,8 +76,7 @@ static inline bool housekeeping_cpu(int cpu, enum hk_type type)
>   static inline bool cpu_is_isolated(int cpu)
>   {
>   	return !housekeeping_test_cpu(cpu, HK_TYPE_DOMAIN) ||
> -	       !housekeeping_test_cpu(cpu, HK_TYPE_TICK) ||
> -	       cpuset_cpu_is_isolated(cpu);
> +	       !housekeeping_test_cpu(cpu, HK_TYPE_TICK);
>   }
>   

You can also remove the "<linux/cpuset.h>" include from isolation.h 
which was added by commit 3232e7aad11e5 ("cgroup/cpuset: Include 
isolated cpuset CPUs in cpu_is_isolated() check") which introduces 
cpuset_cpu_is_isolated().

Cheers,
Longman

Le Wed, Oct 29, 2025 at 02:05:17PM -0400, Waiman Long a écrit :
> On 10/13/25 4:31 PM, Frederic Weisbecker wrote:
> > The set of cpuset isolated CPUs is now included in HK_TYPE_DOMAIN
> > housekeeping cpumask. There is no usecase left interested in just
> > checking what is isolated by cpuset and not by the isolcpus= kernel
> > boot parameter.
> > 
> > Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
> > ---
> >   include/linux/cpuset.h          |  6 ------
> >   include/linux/sched/isolation.h |  3 +--
> >   kernel/cgroup/cpuset.c          | 12 ------------
> >   3 files changed, 1 insertion(+), 20 deletions(-)
> > 
> > diff --git a/include/linux/cpuset.h b/include/linux/cpuset.h
> > index 051d36fec578..a10775a4f702 100644
> > --- a/include/linux/cpuset.h
> > +++ b/include/linux/cpuset.h
> > @@ -78,7 +78,6 @@ extern void cpuset_lock(void);
> >   extern void cpuset_unlock(void);
> >   extern void cpuset_cpus_allowed(struct task_struct *p, struct cpumask *mask);
> >   extern bool cpuset_cpus_allowed_fallback(struct task_struct *p);
> > -extern bool cpuset_cpu_is_isolated(int cpu);
> >   extern nodemask_t cpuset_mems_allowed(struct task_struct *p);
> >   #define cpuset_current_mems_allowed (current->mems_allowed)
> >   void cpuset_init_current_mems_allowed(void);
> > @@ -208,11 +207,6 @@ static inline bool cpuset_cpus_allowed_fallback(struct task_struct *p)
> >   	return false;
> >   }
> > -static inline bool cpuset_cpu_is_isolated(int cpu)
> > -{
> > -	return false;
> > -}
> > -
> >   static inline nodemask_t cpuset_mems_allowed(struct task_struct *p)
> >   {
> >   	return node_possible_map;
> > diff --git a/include/linux/sched/isolation.h b/include/linux/sched/isolation.h
> > index 94d5c835121b..0f50c152cf68 100644
> > --- a/include/linux/sched/isolation.h
> > +++ b/include/linux/sched/isolation.h
> > @@ -76,8 +76,7 @@ static inline bool housekeeping_cpu(int cpu, enum hk_type type)
> >   static inline bool cpu_is_isolated(int cpu)
> >   {
> >   	return !housekeeping_test_cpu(cpu, HK_TYPE_DOMAIN) ||
> > -	       !housekeeping_test_cpu(cpu, HK_TYPE_TICK) ||
> > -	       cpuset_cpu_is_isolated(cpu);
> > +	       !housekeeping_test_cpu(cpu, HK_TYPE_TICK);
> >   }
> 
> You can also remove the "<linux/cpuset.h>" include from isolation.h which
> was added by commit 3232e7aad11e5 ("cgroup/cpuset: Include isolated cpuset
> CPUs in cpu_is_isolated() check") which introduces cpuset_cpu_is_isolated().

Done. Thanks!

-- 
Frederic Weisbecker
SUSE Labs