HK_TYPE_DOMAIN will soon integrate not only boot defined isolcpus= CPUs
but also cpuset isolated partitions.

Housekeeping still needs a way to record what was initially passed
to isolcpus= in order to keep these CPUs isolated after a cpuset
isolated partition is modified or destroyed while containing some of
them.

Create a new HK_TYPE_DOMAIN_BOOT to keep track of those.

Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Reviewed-by: Phil Auld <pauld@redhat.com>
---
 include/linux/sched/isolation.h | 4 ++++
 kernel/sched/isolation.c        | 5 +++--
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/include/linux/sched/isolation.h b/include/linux/sched/isolation.h
index d8501f4709b5..109a2149e21a 100644
--- a/include/linux/sched/isolation.h
+++ b/include/linux/sched/isolation.h
@@ -7,8 +7,12 @@
 #include <linux/tick.h>
 
 enum hk_type {
+	/* Revert of boot-time isolcpus= argument */
+	HK_TYPE_DOMAIN_BOOT,
 	HK_TYPE_DOMAIN,
+	/* Revert of boot-time isolcpus=managed_irq argument */
 	HK_TYPE_MANAGED_IRQ,
+	/* Revert of boot-time nohz_full= or isolcpus=nohz arguments */
 	HK_TYPE_KERNEL_NOISE,
 	HK_TYPE_MAX,
 
diff --git a/kernel/sched/isolation.c b/kernel/sched/isolation.c
index 3ad0d6df6a0a..11a623fa6320 100644
--- a/kernel/sched/isolation.c
+++ b/kernel/sched/isolation.c
@@ -11,6 +11,7 @@
 #include "sched.h"
 
 enum hk_flags {
+	HK_FLAG_DOMAIN_BOOT	= BIT(HK_TYPE_DOMAIN_BOOT),
 	HK_FLAG_DOMAIN		= BIT(HK_TYPE_DOMAIN),
 	HK_FLAG_MANAGED_IRQ	= BIT(HK_TYPE_MANAGED_IRQ),
 	HK_FLAG_KERNEL_NOISE	= BIT(HK_TYPE_KERNEL_NOISE),
@@ -239,7 +240,7 @@ static int __init housekeeping_isolcpus_setup(char *str)
 
 		if (!strncmp(str, "domain,", 7)) {
 			str += 7;
-			flags |= HK_FLAG_DOMAIN;
+			flags |= HK_FLAG_DOMAIN | HK_FLAG_DOMAIN_BOOT;
 			continue;
 		}
 
@@ -269,7 +270,7 @@ static int __init housekeeping_isolcpus_setup(char *str)
 
 	/* Default behaviour for isolcpus without flags */
 	if (!flags)
-		flags |= HK_FLAG_DOMAIN;
+		flags |= HK_FLAG_DOMAIN | HK_FLAG_DOMAIN_BOOT;
 
 	return housekeeping_setup(str, flags);
 }
-- 
2.51.1

On 12/24/25 8:44 AM, Frederic Weisbecker wrote:
> HK_TYPE_DOMAIN will soon integrate not only boot defined isolcpus= CPUs
> but also cpuset isolated partitions.
>
> Housekeeping still needs a way to record what was initially passed
> to isolcpus= in order to keep these CPUs isolated after a cpuset
> isolated partition is modified or destroyed while containing some of
> them.
>
> Create a new HK_TYPE_DOMAIN_BOOT to keep track of those.
>
> Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
> Reviewed-by: Phil Auld <pauld@redhat.com>
> ---
>   include/linux/sched/isolation.h | 4 ++++
>   kernel/sched/isolation.c        | 5 +++--
>   2 files changed, 7 insertions(+), 2 deletions(-)
>
> diff --git a/include/linux/sched/isolation.h b/include/linux/sched/isolation.h
> index d8501f4709b5..109a2149e21a 100644
> --- a/include/linux/sched/isolation.h
> +++ b/include/linux/sched/isolation.h
> @@ -7,8 +7,12 @@
>   #include <linux/tick.h>
>   
>   enum hk_type {
> +	/* Revert of boot-time isolcpus= argument */
> +	HK_TYPE_DOMAIN_BOOT,
>   	HK_TYPE_DOMAIN,
> +	/* Revert of boot-time isolcpus=managed_irq argument */
>   	HK_TYPE_MANAGED_IRQ,
> +	/* Revert of boot-time nohz_full= or isolcpus=nohz arguments */
>   	HK_TYPE_KERNEL_NOISE,
>   	HK_TYPE_MAX,
>   

"Revert" is a verb. The term "Revert of" sound strange to me. I think 
using "Inverse of" will sound better.

Cheers,
Longman

Le Thu, Dec 25, 2025 at 05:27:54PM -0500, Waiman Long a écrit :
> On 12/24/25 8:44 AM, Frederic Weisbecker wrote:
> > HK_TYPE_DOMAIN will soon integrate not only boot defined isolcpus= CPUs
> > but also cpuset isolated partitions.
> > 
> > Housekeeping still needs a way to record what was initially passed
> > to isolcpus= in order to keep these CPUs isolated after a cpuset
> > isolated partition is modified or destroyed while containing some of
> > them.
> > 
> > Create a new HK_TYPE_DOMAIN_BOOT to keep track of those.
> > 
> > Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
> > Reviewed-by: Phil Auld <pauld@redhat.com>
> > ---
> >   include/linux/sched/isolation.h | 4 ++++
> >   kernel/sched/isolation.c        | 5 +++--
> >   2 files changed, 7 insertions(+), 2 deletions(-)
> > 
> > diff --git a/include/linux/sched/isolation.h b/include/linux/sched/isolation.h
> > index d8501f4709b5..109a2149e21a 100644
> > --- a/include/linux/sched/isolation.h
> > +++ b/include/linux/sched/isolation.h
> > @@ -7,8 +7,12 @@
> >   #include <linux/tick.h>
> >   enum hk_type {
> > +	/* Revert of boot-time isolcpus= argument */
> > +	HK_TYPE_DOMAIN_BOOT,
> >   	HK_TYPE_DOMAIN,
> > +	/* Revert of boot-time isolcpus=managed_irq argument */
> >   	HK_TYPE_MANAGED_IRQ,
> > +	/* Revert of boot-time nohz_full= or isolcpus=nohz arguments */
> >   	HK_TYPE_KERNEL_NOISE,
> >   	HK_TYPE_MAX,
> 
> "Revert" is a verb. The term "Revert of" sound strange to me. I think using
> "Inverse of" will sound better.

Somehow I thought it could be a noun as well. At least I wouldn't mind if
it ever turns that way.

Fixing that, thanks.

> 
> Cheers,
> Longman
> 

-- 
Frederic Weisbecker
SUSE Labs