Re: [PATCH 05/33] sched/isolation: Save boot defined domain flags

From: Waiman Long

Date: Thu Dec 25 2025 - 17:28:19 EST


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@xxxxxxxxxx>
Reviewed-by: Phil Auld <pauld@xxxxxxxxxx>
---
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