netdev - Re: [PATCH 18/33] cpuset: Remove cpuset_cpu_is

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Message-ID: <7821fb40-5082-4d11-b539-4c5abc2e572c@redhat.com>
Date: Wed, 29 Oct 2025 14:05:17 -0400
From: Waiman Long <llong@...hat.com>
To: Frederic Weisbecker <frederic@...nel.org>,
 LKML <linux-kernel@...r.kernel.org>
Cc: Michal Koutný <mkoutny@...e.com>,
 Andrew Morton <akpm@...ux-foundation.org>,
 Bjorn Helgaas <bhelgaas@...gle.com>,
 Catalin Marinas <catalin.marinas@....com>, Danilo Krummrich
 <dakr@...nel.org>, "David S . Miller" <davem@...emloft.net>,
 Eric Dumazet <edumazet@...gle.com>, Gabriele Monaco <gmonaco@...hat.com>,
 Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
 Ingo Molnar <mingo@...hat.com>, Jakub Kicinski <kuba@...nel.org>,
 Jens Axboe <axboe@...nel.dk>, Johannes Weiner <hannes@...xchg.org>,
 Lai Jiangshan <jiangshanlai@...il.com>,
 Marco Crivellari <marco.crivellari@...e.com>, Michal Hocko
 <mhocko@...e.com>, Muchun Song <muchun.song@...ux.dev>,
 Paolo Abeni <pabeni@...hat.com>, Peter Zijlstra <peterz@...radead.org>,
 Phil Auld <pauld@...hat.com>, "Rafael J . Wysocki" <rafael@...nel.org>,
 Roman Gushchin <roman.gushchin@...ux.dev>,
 Shakeel Butt <shakeel.butt@...ux.dev>, Simon Horman <horms@...nel.org>,
 Tejun Heo <tj@...nel.org>, Thomas Gleixner <tglx@...utronix.de>,
 Vlastimil Babka <vbabka@...e.cz>, Will Deacon <will@...nel.org>,
 cgroups@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
 linux-block@...r.kernel.org, linux-mm@...ck.org, linux-pci@...r.kernel.org,
 netdev@...r.kernel.org
Subject: Re: [PATCH 18/33] cpuset: Remove cpuset_cpu_is_isolated()

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@...nel.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