* [PATCH sched_ext/for-7.1] sched_ext: Guard cpu_smt_mask() with CONFIG_SCHED_SMT
@ 2026-03-22 6:51 Andrea Righi
2026-03-22 7:35 ` Cheng-Yang Chou
2026-03-22 20:06 ` Tejun Heo
0 siblings, 2 replies; 3+ messages in thread
From: Andrea Righi @ 2026-03-22 6:51 UTC (permalink / raw)
To: Tejun Heo, David Vernet, Changwoo Min
Cc: Cheng-Yang Chou, sched-ext, linux-kernel, kernel test robot
Wrap cpu_smt_mask() usage with CONFIG_SCHED_SMT to avoid build failures
on kernels built without SMT support.
Fixes: 2197cecdb02c ("sched_ext: idle: Prioritize idle SMT sibling")
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202603221422.XIueJOE9-lkp@intel.com/
Signed-off-by: Andrea Righi <arighi@nvidia.com>
---
kernel/sched/ext_idle.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/kernel/sched/ext_idle.c b/kernel/sched/ext_idle.c
index d9596427b5aa1..857d8e902b448 100644
--- a/kernel/sched/ext_idle.c
+++ b/kernel/sched/ext_idle.c
@@ -622,6 +622,7 @@ s32 scx_select_cpu_dfl(struct task_struct *p, s32 prev_cpu, u64 wake_flags,
goto out_unlock;
}
+#ifdef CONFIG_SCHED_SMT
/*
* Use @prev_cpu's sibling if it's idle.
*/
@@ -633,6 +634,7 @@ s32 scx_select_cpu_dfl(struct task_struct *p, s32 prev_cpu, u64 wake_flags,
goto out_unlock;
}
}
+#endif
/*
* Search for any idle CPU in the same LLC domain.
--
2.53.0
^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [PATCH sched_ext/for-7.1] sched_ext: Guard cpu_smt_mask() with CONFIG_SCHED_SMT
2026-03-22 6:51 [PATCH sched_ext/for-7.1] sched_ext: Guard cpu_smt_mask() with CONFIG_SCHED_SMT Andrea Righi
@ 2026-03-22 7:35 ` Cheng-Yang Chou
2026-03-22 20:06 ` Tejun Heo
1 sibling, 0 replies; 3+ messages in thread
From: Cheng-Yang Chou @ 2026-03-22 7:35 UTC (permalink / raw)
To: Andrea Righi
Cc: Tejun Heo, David Vernet, Changwoo Min, sched-ext, linux-kernel,
kernel test robot
Hi Andrea,
On Sun, Mar 22, 2026 at 07:51:46AM +0100, Andrea Righi wrote:
> Wrap cpu_smt_mask() usage with CONFIG_SCHED_SMT to avoid build failures
> on kernels built without SMT support.
>
> Fixes: 2197cecdb02c ("sched_ext: idle: Prioritize idle SMT sibling")
> Reported-by: kernel test robot <lkp@intel.com>
> Closes: https://lore.kernel.org/oe-kbuild-all/202603221422.XIueJOE9-lkp@intel.com/
> Signed-off-by: Andrea Righi <arighi@nvidia.com>
> ---
> kernel/sched/ext_idle.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/kernel/sched/ext_idle.c b/kernel/sched/ext_idle.c
> index d9596427b5aa1..857d8e902b448 100644
> --- a/kernel/sched/ext_idle.c
> +++ b/kernel/sched/ext_idle.c
> @@ -622,6 +622,7 @@ s32 scx_select_cpu_dfl(struct task_struct *p, s32 prev_cpu, u64 wake_flags,
> goto out_unlock;
> }
>
> +#ifdef CONFIG_SCHED_SMT
> /*
> * Use @prev_cpu's sibling if it's idle.
> */
> @@ -633,6 +634,7 @@ s32 scx_select_cpu_dfl(struct task_struct *p, s32 prev_cpu, u64 wake_flags,
> goto out_unlock;
> }
> }
> +#endif
>
> /*
> * Search for any idle CPU in the same LLC domain.
> --
> 2.53.0
>
Tested with the robot's config and the error is gone.
Reviewed-by: Cheng-Yang Chou <yphbchou0911@gmail.com>
--
Thanks,
Cheng-Yang
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH sched_ext/for-7.1] sched_ext: Guard cpu_smt_mask() with CONFIG_SCHED_SMT
2026-03-22 6:51 [PATCH sched_ext/for-7.1] sched_ext: Guard cpu_smt_mask() with CONFIG_SCHED_SMT Andrea Righi
2026-03-22 7:35 ` Cheng-Yang Chou
@ 2026-03-22 20:06 ` Tejun Heo
1 sibling, 0 replies; 3+ messages in thread
From: Tejun Heo @ 2026-03-22 20:06 UTC (permalink / raw)
To: Andrea Righi, sched-ext, David Vernet, Changwoo Min
Cc: Cheng-Yang Chou, kernel test robot, Emil Tsalapatis, linux-kernel
Applied to sched_ext/for-7.1.
Thanks.
--
tejun
^ permalink raw reply [flat|nested] 3+ messages in thread
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2026-03-22 6:51 [PATCH sched_ext/for-7.1] sched_ext: Guard cpu_smt_mask() with CONFIG_SCHED_SMT Andrea Righi
2026-03-22 7:35 ` Cheng-Yang Chou
2026-03-22 20:06 ` Tejun Heo
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