[PATCH] s390/topology: Switch to common cpu capacity code

[PATCH] s390/topology: Switch to common cpu capacity code

[Mete Durlu]

s390 implementation of cpu capacity management infrastructure code does
not do anything different than its common code counterpart. Switch to
common code functions and remove the smp_cpu_*_capacity() functions.
Make s390 code better align with other architectures which utilize
cpu_capacity. No functional changes.

Allow cpu_capacity attributes inside sysfs to accurately reflect cpu
capacity.
ex:

$ cat /sys/devices/system/cpu/cpu0/polarization
vertical:high
$ cat /sys/devices/system/cpu/cpu0/cpu_capacity
1024

$ cat /sys/devices/system/cpu/cpu40/polarization
vertical:low
$ cat /sys/devices/system/cpu/cpu40/cpu_capacity
128

Prior to commit 6bceea7a1e07 ("arch_topology: Relocate cpu_scale to
topology.[h|c]") cpu_capacity attribute was only available to the common
arch_topology driver's users. Reflect the correct values to the newly
made available attributes.

Signed-off-by: Mete Durlu <meted@linux.ibm.com>
---
 arch/s390/include/asm/processor.h |  1 -
 arch/s390/include/asm/smp.h       |  4 +---
 arch/s390/kernel/smp.c            | 16 +++-------------
 arch/s390/kernel/topology.c       |  2 +-
 4 files changed, 5 insertions(+), 18 deletions(-)

diff --git a/arch/s390/include/asm/processor.h b/arch/s390/include/asm/processor.h
index be8369115f6d..9434c76c25b8 100644
--- a/arch/s390/include/asm/processor.h
+++ b/arch/s390/include/asm/processor.h
@@ -46,7 +46,6 @@ struct pcpu {
 	unsigned long ec_mask;		/* bit mask for ec_xxx functions */
 	unsigned long ec_clk;		/* sigp timestamp for ec_xxx */
 	unsigned long flags;		/* per CPU flags */
-	unsigned long capacity;		/* cpu capacity for scheduler */
 	signed char state;		/* physical cpu state */
 	signed char polarization;	/* physical polarization */
 	u16 address;			/* physical cpu address */
diff --git a/arch/s390/include/asm/smp.h b/arch/s390/include/asm/smp.h
index fb2bdbf35da5..a6c621e0491c 100644
--- a/arch/s390/include/asm/smp.h
+++ b/arch/s390/include/asm/smp.h
@@ -30,7 +30,7 @@ static __always_inline unsigned int raw_smp_processor_id(void)
 	return cpu;
 }
 
-#define arch_scale_cpu_capacity smp_cpu_get_capacity
+#define arch_scale_cpu_capacity topology_get_cpu_scale
 
 extern struct mutex smp_cpu_state_mutex;
 extern unsigned int smp_cpu_mt_shift;
@@ -53,9 +53,7 @@ extern void smp_save_dump_secondary_cpus(void);
 extern void smp_yield_cpu(int cpu);
 extern void smp_cpu_set_polarization(int cpu, int val);
 extern int smp_cpu_get_polarization(int cpu);
-extern void smp_cpu_set_capacity(int cpu, unsigned long val);
 extern void smp_set_core_capacity(int cpu, unsigned long val);
-extern unsigned long smp_cpu_get_capacity(int cpu);
 extern int smp_cpu_get_cpu_address(int cpu);
 extern void smp_fill_possible_mask(void);
 extern void smp_detect_cpus(void);
diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c
index 167c72803ccf..32499cad86f0 100644
--- a/arch/s390/kernel/smp.c
+++ b/arch/s390/kernel/smp.c
@@ -659,23 +659,13 @@ int smp_cpu_get_polarization(int cpu)
 	return per_cpu(pcpu_devices, cpu).polarization;
 }
 
-void smp_cpu_set_capacity(int cpu, unsigned long val)
-{
-	per_cpu(pcpu_devices, cpu).capacity = val;
-}
-
-unsigned long smp_cpu_get_capacity(int cpu)
-{
-	return per_cpu(pcpu_devices, cpu).capacity;
-}
-
 void smp_set_core_capacity(int cpu, unsigned long val)
 {
 	int i;
 
 	cpu = smp_get_base_cpu(cpu);
 	for (i = cpu; (i <= cpu + smp_cpu_mtid) && (i < nr_cpu_ids); i++)
-		smp_cpu_set_capacity(i, val);
+		topology_set_cpu_scale(i, val);
 }
 
 int smp_cpu_get_cpu_address(int cpu)
@@ -727,7 +717,7 @@ static int smp_add_core(struct sclp_core_entry *core, cpumask_t *avail,
 		else
 			pcpu->state = CPU_STATE_STANDBY;
 		smp_cpu_set_polarization(cpu, POLARIZATION_UNKNOWN);
-		smp_cpu_set_capacity(cpu, CPU_CAPACITY_HIGH);
+		topology_set_cpu_scale(cpu, CPU_CAPACITY_HIGH);
 		set_cpu_present(cpu, true);
 		if (!early && arch_register_cpu(cpu))
 			set_cpu_present(cpu, false);
@@ -967,7 +957,7 @@ void __init smp_prepare_boot_cpu(void)
 	ipl_pcpu->state = CPU_STATE_CONFIGURED;
 	lc->pcpu = (unsigned long)ipl_pcpu;
 	smp_cpu_set_polarization(0, POLARIZATION_UNKNOWN);
-	smp_cpu_set_capacity(0, CPU_CAPACITY_HIGH);
+	topology_set_cpu_scale(0, CPU_CAPACITY_HIGH);
 }
 
 void __init smp_setup_processor_id(void)
diff --git a/arch/s390/kernel/topology.c b/arch/s390/kernel/topology.c
index 1377c6f3f670..42fc0294f543 100644
--- a/arch/s390/kernel/topology.c
+++ b/arch/s390/kernel/topology.c
@@ -147,7 +147,7 @@ static void add_cpus_to_mask(struct topology_core *tl_core,
 			cpumask_set_cpu(cpu, &book->mask);
 			cpumask_set_cpu(cpu, &socket->mask);
 			smp_cpu_set_polarization(cpu, tl_core->pp);
-			smp_cpu_set_capacity(cpu, CPU_CAPACITY_HIGH);
+			topology_set_cpu_scale(cpu, CPU_CAPACITY_HIGH);
 		}
 	}
 }

---
base-commit: 66498c75b4f8017f62d720d9b59675bdf3abce91
change-id: 20260825-common_capacity-ae3fb766749b

Best regards,
-- 
Mete Durlu <meted@linux.ibm.com>

Re: [PATCH] s390/topology: Switch to common cpu capacity code

[sashiko-bot]

> s390 implementation of cpu capacity management infrastructure code does
> not do anything different than its common code counterpart. Switch to
> common code functions and remove the smp_cpu_*_capacity() functions.
> Make s390 code better align with other architectures which utilize
> cpu_capacity. No functional changes.
> 
> Allow cpu_capacity attributes inside sysfs to accurately reflect cpu
> capacity.
> ex:
> 
> $ cat /sys/devices/system/cpu/cpu0/polarization
> vertical:high
> $ cat /sys/devices/system/cpu/cpu0/cpu_capacity
> 1024
> 
> $ cat /sys/devices/system/cpu/cpu40/polarization
> vertical:low
> $ cat /sys/devices/system/cpu/cpu40/cpu_capacity
> 128
> 
> Prior to commit 6bceea7a1e07 ("arch_topology: Relocate cpu_scale to
> topology.[h|c]") cpu_capacity attribute was only available to the common
> arch_topology driver's users. Reflect the correct values to the newly
> made available attributes.
> 
> Signed-off-by: Mete Durlu <meted@linux.ibm.com>

Sashiko has reviewed this patch and found no issues. It looks great!

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260825-common_capacity-v1-1-1cdfa3ad5e14@linux.ibm.com?part=1

Re: [PATCH] s390/topology: Switch to common cpu capacity code

[Heiko Carstens]

On Tue, Aug 25, 2026 at 02:58:20PM +0200, Mete Durlu wrote:
> s390 implementation of cpu capacity management infrastructure code does
> not do anything different than its common code counterpart. Switch to
> common code functions and remove the smp_cpu_*_capacity() functions.
> Make s390 code better align with other architectures which utilize
> cpu_capacity. No functional changes.
> 
> Allow cpu_capacity attributes inside sysfs to accurately reflect cpu
> capacity.
> ex:
> 
> $ cat /sys/devices/system/cpu/cpu0/polarization
> vertical:high
> $ cat /sys/devices/system/cpu/cpu0/cpu_capacity
> 1024
> 
> $ cat /sys/devices/system/cpu/cpu40/polarization
> vertical:low
> $ cat /sys/devices/system/cpu/cpu40/cpu_capacity
> 128
> 
> Prior to commit 6bceea7a1e07 ("arch_topology: Relocate cpu_scale to
> topology.[h|c]") cpu_capacity attribute was only available to the common
> arch_topology driver's users. Reflect the correct values to the newly
> made available attributes.
> 
> Signed-off-by: Mete Durlu <meted@linux.ibm.com>
> ---
>  arch/s390/include/asm/processor.h |  1 -
>  arch/s390/include/asm/smp.h       |  4 +---
>  arch/s390/kernel/smp.c            | 16 +++-------------
>  arch/s390/kernel/topology.c       |  2 +-
>  4 files changed, 5 insertions(+), 18 deletions(-)

Reviewed-by: Heiko Carstens <hca@linux.ibm.com>

Re: [PATCH] s390/topology: Switch to common cpu capacity code

[Vasily Gorbik]

On Tue, Aug 25, 2026 at 02:58:20PM +0200, Mete Durlu wrote:
> s390 implementation of cpu capacity management infrastructure code does
> not do anything different than its common code counterpart. Switch to
> common code functions and remove the smp_cpu_*_capacity() functions.
> Make s390 code better align with other architectures which utilize
> cpu_capacity. No functional changes.
> 
> Allow cpu_capacity attributes inside sysfs to accurately reflect cpu
> capacity.
> ex:
> 
> $ cat /sys/devices/system/cpu/cpu0/polarization
> vertical:high
> $ cat /sys/devices/system/cpu/cpu0/cpu_capacity
> 1024
> 
> $ cat /sys/devices/system/cpu/cpu40/polarization
> vertical:low
> $ cat /sys/devices/system/cpu/cpu40/cpu_capacity
> 128
> 
> Prior to commit 6bceea7a1e07 ("arch_topology: Relocate cpu_scale to
> topology.[h|c]") cpu_capacity attribute was only available to the common
> arch_topology driver's users. Reflect the correct values to the newly
> made available attributes.
> 
> Signed-off-by: Mete Durlu <meted@linux.ibm.com>
> ---
>  arch/s390/include/asm/processor.h |  1 -
>  arch/s390/include/asm/smp.h       |  4 +---
>  arch/s390/kernel/smp.c            | 16 +++-------------
>  arch/s390/kernel/topology.c       |  2 +-
>  4 files changed, 5 insertions(+), 18 deletions(-)

Applied, thank you!