From: Alexey Makhalov <alexey.makhalov@broadcom.com>
To: Juergen Gross <jgross@suse.com>
Cc: Ajay Kaher <ajay.kaher@broadcom.com>,
loongarch@lists.linux.dev, x86@kernel.org,
virtualization@lists.linux.dev, linux-kernel@vger.kernel.org,
linuxppc-dev@lists.ozlabs.org, linux-riscv@lists.infradead.org,
kvm@vger.kernel.org,
Broadcom internal kernel review list
<bcm-kernel-feedback-list@broadcom.com>,
Russell King <linux@armlinux.org.uk>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>,
Huacai Chen <chenhuacai@kernel.org>,
WANG Xuerui <kernel@xen0n.name>,
Madhavan Srinivasan <maddy@linux.ibm.com>,
Michael Ellerman <mpe@ellerman.id.au>,
Nicholas Piggin <npiggin@gmail.com>,
Christophe Leroy <christophe.leroy@csgroup.eu>,
Paul Walmsley <pjw@kernel.org>,
Palmer Dabbelt <palmer@dabbelt.com>,
Albert Ou <aou@eecs.berkeley.edu>,
Alexandre Ghiti <alex@ghiti.fr>,
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Dave Hansen <dave.hansen@linux.intel.com>,
"H. Peter Anvin" <hpa@zytor.com>,
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Peter Zijlstra <peterz@infradead.org>,
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xen-devel@lists.xenproject.org
Subject: Re: [PATCH v3 06/21] sched: Move clock related paravirt code to kernel/sched
Date: Wed, 7 Jan 2026 14:48:51 -0800 [thread overview]
Message-ID: <ce5d54a2-fed5-4039-846d-b0ae11d15810@broadcom.com> (raw)
In-Reply-To: <20251006074606.1266-7-jgross@suse.com>
On 10/6/25 12:45 AM, Juergen Gross wrote:
> Paravirt clock related functions are available in multiple archs.
>
> In order to share the common parts, move the common static keys
> to kernel/sched/ and remove them from the arch specific files.
>
> Make a common paravirt_steal_clock() implementation available in
> kernel/sched/cputime.c, guarding it with a new config option
> CONFIG_HAVE_PV_STEAL_CLOCK_GEN, which can be selected by an arch
> in case it wants to use that common variant.
>
> Signed-off-by: Juergen Gross <jgross@suse.com>
> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
> ---
> arch/Kconfig | 3 +++
> arch/arm/include/asm/paravirt.h | 4 ----
> arch/arm/kernel/paravirt.c | 3 ---
> arch/arm64/include/asm/paravirt.h | 4 ----
> arch/arm64/kernel/paravirt.c | 4 +---
> arch/loongarch/include/asm/paravirt.h | 3 ---
> arch/loongarch/kernel/paravirt.c | 3 +--
> arch/powerpc/include/asm/paravirt.h | 3 ---
> arch/powerpc/platforms/pseries/setup.c | 4 +---
> arch/riscv/include/asm/paravirt.h | 4 ----
> arch/riscv/kernel/paravirt.c | 4 +---
> arch/x86/include/asm/paravirt.h | 4 ----
> arch/x86/kernel/cpu/vmware.c | 1 +
> arch/x86/kernel/kvm.c | 1 +
> arch/x86/kernel/paravirt.c | 3 ---
> drivers/xen/time.c | 1 +
> include/linux/sched/cputime.h | 18 ++++++++++++++++++
> kernel/sched/core.c | 5 +++++
> kernel/sched/cputime.c | 13 +++++++++++++
> kernel/sched/sched.h | 2 +-
> 20 files changed, 47 insertions(+), 40 deletions(-)
>
> diff --git a/arch/Kconfig b/arch/Kconfig
> index ebe08b9186ad..f310ac346fa4 100644
> --- a/arch/Kconfig
> +++ b/arch/Kconfig
> @@ -1051,6 +1051,9 @@ config HAVE_IRQ_TIME_ACCOUNTING
> Archs need to ensure they use a high enough resolution clock to
> support irq time accounting and then call enable_sched_clock_irqtime().
>
> +config HAVE_PV_STEAL_CLOCK_GEN
> + bool
> +
> config HAVE_MOVE_PUD
> bool
> help
> diff --git a/arch/arm/include/asm/paravirt.h b/arch/arm/include/asm/paravirt.h
> index 95d5b0d625cd..69da4bdcf856 100644
> --- a/arch/arm/include/asm/paravirt.h
> +++ b/arch/arm/include/asm/paravirt.h
> @@ -5,10 +5,6 @@
> #ifdef CONFIG_PARAVIRT
> #include <linux/static_call_types.h>
>
> -struct static_key;
> -extern struct static_key paravirt_steal_enabled;
> -extern struct static_key paravirt_steal_rq_enabled;
> -
> u64 dummy_steal_clock(int cpu);
>
> DECLARE_STATIC_CALL(pv_steal_clock, dummy_steal_clock);
> diff --git a/arch/arm/kernel/paravirt.c b/arch/arm/kernel/paravirt.c
> index 7dd9806369fb..3895a5578852 100644
> --- a/arch/arm/kernel/paravirt.c
> +++ b/arch/arm/kernel/paravirt.c
> @@ -12,9 +12,6 @@
> #include <linux/static_call.h>
> #include <asm/paravirt.h>
>
> -struct static_key paravirt_steal_enabled;
> -struct static_key paravirt_steal_rq_enabled;
> -
> static u64 native_steal_clock(int cpu)
> {
> return 0;
> diff --git a/arch/arm64/include/asm/paravirt.h b/arch/arm64/include/asm/paravirt.h
> index 9aa193e0e8f2..c9f7590baacb 100644
> --- a/arch/arm64/include/asm/paravirt.h
> +++ b/arch/arm64/include/asm/paravirt.h
> @@ -5,10 +5,6 @@
> #ifdef CONFIG_PARAVIRT
> #include <linux/static_call_types.h>
>
> -struct static_key;
> -extern struct static_key paravirt_steal_enabled;
> -extern struct static_key paravirt_steal_rq_enabled;
> -
> u64 dummy_steal_clock(int cpu);
>
> DECLARE_STATIC_CALL(pv_steal_clock, dummy_steal_clock);
> diff --git a/arch/arm64/kernel/paravirt.c b/arch/arm64/kernel/paravirt.c
> index aa718d6a9274..943b60ce12f4 100644
> --- a/arch/arm64/kernel/paravirt.c
> +++ b/arch/arm64/kernel/paravirt.c
> @@ -19,14 +19,12 @@
> #include <linux/slab.h>
> #include <linux/types.h>
> #include <linux/static_call.h>
> +#include <linux/sched/cputime.h>
>
> #include <asm/paravirt.h>
> #include <asm/pvclock-abi.h>
> #include <asm/smp_plat.h>
>
> -struct static_key paravirt_steal_enabled;
> -struct static_key paravirt_steal_rq_enabled;
> -
> static u64 native_steal_clock(int cpu)
> {
> return 0;
> diff --git a/arch/loongarch/include/asm/paravirt.h b/arch/loongarch/include/asm/paravirt.h
> index 3f4323603e6a..d219ea0d98ac 100644
> --- a/arch/loongarch/include/asm/paravirt.h
> +++ b/arch/loongarch/include/asm/paravirt.h
> @@ -5,9 +5,6 @@
> #ifdef CONFIG_PARAVIRT
>
> #include <linux/static_call_types.h>
> -struct static_key;
> -extern struct static_key paravirt_steal_enabled;
> -extern struct static_key paravirt_steal_rq_enabled;
>
> u64 dummy_steal_clock(int cpu);
> DECLARE_STATIC_CALL(pv_steal_clock, dummy_steal_clock);
> diff --git a/arch/loongarch/kernel/paravirt.c b/arch/loongarch/kernel/paravirt.c
> index b1b51f920b23..8caaa94fed1a 100644
> --- a/arch/loongarch/kernel/paravirt.c
> +++ b/arch/loongarch/kernel/paravirt.c
> @@ -6,11 +6,10 @@
> #include <linux/kvm_para.h>
> #include <linux/reboot.h>
> #include <linux/static_call.h>
> +#include <linux/sched/cputime.h>
> #include <asm/paravirt.h>
>
> static int has_steal_clock;
> -struct static_key paravirt_steal_enabled;
> -struct static_key paravirt_steal_rq_enabled;
> static DEFINE_PER_CPU(struct kvm_steal_time, steal_time) __aligned(64);
> DEFINE_STATIC_KEY_FALSE(virt_spin_lock_key);
>
> diff --git a/arch/powerpc/include/asm/paravirt.h b/arch/powerpc/include/asm/paravirt.h
> index b78b82d66057..92343a23ad15 100644
> --- a/arch/powerpc/include/asm/paravirt.h
> +++ b/arch/powerpc/include/asm/paravirt.h
> @@ -23,9 +23,6 @@ static inline bool is_shared_processor(void)
> }
>
> #ifdef CONFIG_PARAVIRT_TIME_ACCOUNTING
> -extern struct static_key paravirt_steal_enabled;
> -extern struct static_key paravirt_steal_rq_enabled;
> -
> u64 pseries_paravirt_steal_clock(int cpu);
>
> static inline u64 paravirt_steal_clock(int cpu)
> diff --git a/arch/powerpc/platforms/pseries/setup.c b/arch/powerpc/platforms/pseries/setup.c
> index b10a25325238..50b26ed8432d 100644
> --- a/arch/powerpc/platforms/pseries/setup.c
> +++ b/arch/powerpc/platforms/pseries/setup.c
> @@ -42,6 +42,7 @@
> #include <linux/memblock.h>
> #include <linux/swiotlb.h>
> #include <linux/seq_buf.h>
> +#include <linux/sched/cputime.h>
>
> #include <asm/mmu.h>
> #include <asm/processor.h>
> @@ -83,9 +84,6 @@ DEFINE_STATIC_KEY_FALSE(shared_processor);
> EXPORT_SYMBOL(shared_processor);
>
> #ifdef CONFIG_PARAVIRT_TIME_ACCOUNTING
> -struct static_key paravirt_steal_enabled;
> -struct static_key paravirt_steal_rq_enabled;
> -
> static bool steal_acc = true;
> static int __init parse_no_stealacc(char *arg)
> {
> diff --git a/arch/riscv/include/asm/paravirt.h b/arch/riscv/include/asm/paravirt.h
> index c0abde70fc2c..17e5e39c72c0 100644
> --- a/arch/riscv/include/asm/paravirt.h
> +++ b/arch/riscv/include/asm/paravirt.h
> @@ -5,10 +5,6 @@
> #ifdef CONFIG_PARAVIRT
> #include <linux/static_call_types.h>
>
> -struct static_key;
> -extern struct static_key paravirt_steal_enabled;
> -extern struct static_key paravirt_steal_rq_enabled;
> -
> u64 dummy_steal_clock(int cpu);
>
> DECLARE_STATIC_CALL(pv_steal_clock, dummy_steal_clock);
> diff --git a/arch/riscv/kernel/paravirt.c b/arch/riscv/kernel/paravirt.c
> index fa6b0339a65d..d3c334f16172 100644
> --- a/arch/riscv/kernel/paravirt.c
> +++ b/arch/riscv/kernel/paravirt.c
> @@ -16,15 +16,13 @@
> #include <linux/printk.h>
> #include <linux/static_call.h>
> #include <linux/types.h>
> +#include <linux/sched/cputime.h>
>
> #include <asm/barrier.h>
> #include <asm/page.h>
> #include <asm/paravirt.h>
> #include <asm/sbi.h>
>
> -struct static_key paravirt_steal_enabled;
> -struct static_key paravirt_steal_rq_enabled;
> -
> static u64 native_steal_clock(int cpu)
> {
> return 0;
> diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h
> index 1344d2fb2b86..0ef797ea8440 100644
> --- a/arch/x86/include/asm/paravirt.h
> +++ b/arch/x86/include/asm/paravirt.h
> @@ -30,10 +30,6 @@ static __always_inline u64 paravirt_sched_clock(void)
> return static_call(pv_sched_clock)();
> }
>
> -struct static_key;
> -extern struct static_key paravirt_steal_enabled;
> -extern struct static_key paravirt_steal_rq_enabled;
> -
> __visible void __native_queued_spin_unlock(struct qspinlock *lock);
> bool pv_is_native_spin_unlock(void);
> __visible bool __native_vcpu_is_preempted(long cpu);
> diff --git a/arch/x86/kernel/cpu/vmware.c b/arch/x86/kernel/cpu/vmware.c
> index cb3f900c46fc..a3e6936839b1 100644
> --- a/arch/x86/kernel/cpu/vmware.c
> +++ b/arch/x86/kernel/cpu/vmware.c
> @@ -29,6 +29,7 @@
> #include <linux/efi.h>
> #include <linux/reboot.h>
> #include <linux/static_call.h>
> +#include <linux/sched/cputime.h>
> #include <asm/div64.h>
> #include <asm/x86_init.h>
> #include <asm/hypervisor.h>
> diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
> index b67d7c59dca0..d54fd2bc0402 100644
> --- a/arch/x86/kernel/kvm.c
> +++ b/arch/x86/kernel/kvm.c
> @@ -29,6 +29,7 @@
> #include <linux/syscore_ops.h>
> #include <linux/cc_platform.h>
> #include <linux/efi.h>
> +#include <linux/sched/cputime.h>
> #include <asm/timer.h>
> #include <asm/cpu.h>
> #include <asm/traps.h>
> diff --git a/arch/x86/kernel/paravirt.c b/arch/x86/kernel/paravirt.c
> index ab3e172dcc69..a3ba4747be1c 100644
> --- a/arch/x86/kernel/paravirt.c
> +++ b/arch/x86/kernel/paravirt.c
> @@ -60,9 +60,6 @@ void __init native_pv_lock_init(void)
> static_branch_enable(&virt_spin_lock_key);
> }
>
> -struct static_key paravirt_steal_enabled;
> -struct static_key paravirt_steal_rq_enabled;
> -
> static u64 native_steal_clock(int cpu)
> {
> return 0;
> diff --git a/drivers/xen/time.c b/drivers/xen/time.c
> index 5683383d2305..d360ded2ef39 100644
> --- a/drivers/xen/time.c
> +++ b/drivers/xen/time.c
> @@ -8,6 +8,7 @@
> #include <linux/gfp.h>
> #include <linux/slab.h>
> #include <linux/static_call.h>
> +#include <linux/sched/cputime.h>
>
> #include <asm/paravirt.h>
> #include <asm/xen/hypervisor.h>
> diff --git a/include/linux/sched/cputime.h b/include/linux/sched/cputime.h
> index 5f8fd5b24a2e..e90efaf6d26e 100644
> --- a/include/linux/sched/cputime.h
> +++ b/include/linux/sched/cputime.h
> @@ -2,6 +2,7 @@
> #ifndef _LINUX_SCHED_CPUTIME_H
> #define _LINUX_SCHED_CPUTIME_H
>
> +#include <linux/static_call_types.h>
> #include <linux/sched/signal.h>
>
> /*
> @@ -180,4 +181,21 @@ static inline void prev_cputime_init(struct prev_cputime *prev)
> extern unsigned long long
> task_sched_runtime(struct task_struct *task);
>
> +#ifdef CONFIG_PARAVIRT
> +struct static_key;
> +extern struct static_key paravirt_steal_enabled;
> +extern struct static_key paravirt_steal_rq_enabled;
> +
> +#ifdef CONFIG_HAVE_PV_STEAL_CLOCK_GEN
> +u64 dummy_steal_clock(int cpu);
> +
> +DECLARE_STATIC_CALL(pv_steal_clock, dummy_steal_clock);
> +
> +static inline u64 paravirt_steal_clock(int cpu)
> +{
> + return static_call(pv_steal_clock)(cpu);
> +}
> +#endif
> +#endif
> +
> #endif /* _LINUX_SCHED_CPUTIME_H */
> diff --git a/kernel/sched/core.c b/kernel/sched/core.c
> index 198d2dd45f59..06a9a20820d4 100644
> --- a/kernel/sched/core.c
> +++ b/kernel/sched/core.c
> @@ -769,6 +769,11 @@ struct rq *task_rq_lock(struct task_struct *p, struct rq_flags *rf)
> * RQ-clock updating methods:
> */
>
> +/* Use CONFIG_PARAVIRT as this will avoid more #ifdef in arch code. */
> +#ifdef CONFIG_PARAVIRT
> +struct static_key paravirt_steal_rq_enabled;
> +#endif
> +
> static void update_rq_clock_task(struct rq *rq, s64 delta)
> {
> /*
> diff --git a/kernel/sched/cputime.c b/kernel/sched/cputime.c
> index 7097de2c8cda..ed8f71e08047 100644
> --- a/kernel/sched/cputime.c
> +++ b/kernel/sched/cputime.c
> @@ -251,6 +251,19 @@ void __account_forceidle_time(struct task_struct *p, u64 delta)
> * ticks are not redelivered later. Due to that, this function may on
> * occasion account more time than the calling functions think elapsed.
> */
> +#ifdef CONFIG_PARAVIRT
> +struct static_key paravirt_steal_enabled;
> +
> +#ifdef CONFIG_HAVE_PV_STEAL_CLOCK_GEN
> +static u64 native_steal_clock(int cpu)
> +{
> + return 0;
> +}
> +
> +DEFINE_STATIC_CALL(pv_steal_clock, native_steal_clock);
> +#endif
> +#endif
> +
> static __always_inline u64 steal_account_process_time(u64 maxtime)
> {
> #ifdef CONFIG_PARAVIRT
> diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
> index 0d0fa13cab5c..72fd9268008e 100644
> --- a/kernel/sched/sched.h
> +++ b/kernel/sched/sched.h
> @@ -82,7 +82,7 @@ struct rt_rq;
> struct sched_group;
> struct cpuidle_state;
>
> -#ifdef CONFIG_PARAVIRT
> +#if defined(CONFIG_PARAVIRT) && !defined(CONFIG_HAVE_PV_STEAL_CLOCK_GEN)
> # include <asm/paravirt.h>
> #endif
>
Acked-by: Alexey Makhalov <alexey.makhalov@broadcom.com>
next prev parent reply other threads:[~2026-01-07 22:48 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-10-06 7:45 [PATCH v3 00/21] paravirt: cleanup and reorg Juergen Gross
2025-10-06 7:45 ` [PATCH v3 02/21] x86/paravirt: Remove some unneeded struct declarations Juergen Gross
2025-10-23 12:14 ` Borislav Petkov
2025-10-06 7:45 ` [PATCH v3 03/21] x86/paravirt: Remove PARAVIRT_DEBUG config option Juergen Gross
2025-10-06 7:45 ` [PATCH v3 04/21] x86/paravirt: Move thunk macros to paravirt_types.h Juergen Gross
2025-10-06 7:45 ` [PATCH v3 05/21] paravirt: Remove asm/paravirt_api_clock.h Juergen Gross
2025-10-15 16:02 ` Shrikanth Hegde
2025-10-06 7:45 ` [PATCH v3 06/21] sched: Move clock related paravirt code to kernel/sched Juergen Gross
2026-01-07 22:48 ` Alexey Makhalov [this message]
2025-10-06 7:45 ` [PATCH v3 07/21] arm/paravirt: Use common code for paravirt_steal_clock() Juergen Gross
2025-10-06 7:45 ` [PATCH v3 08/21] arm64/paravirt: " Juergen Gross
2025-10-06 7:45 ` [PATCH v3 09/21] loongarch/paravirt: " Juergen Gross
2025-11-24 9:52 ` Bibo Mao
2025-10-06 7:45 ` [PATCH v3 10/21] riscv/paravirt: " Juergen Gross
2025-10-06 7:45 ` [PATCH v3 11/21] x86/paravirt: " Juergen Gross
2025-10-06 7:45 ` [PATCH v3 12/21] x86/paravirt: Move paravirt_sched_clock() related code into tsc.c Juergen Gross
2025-10-06 7:45 ` [PATCH v3 13/21] x86/paravirt: Introduce new paravirt-base.h header Juergen Gross
2025-10-06 7:45 ` [PATCH v3 14/21] x86/paravirt: Move pv_native_*() prototypes to paravirt.c Juergen Gross
2025-10-06 7:46 ` [PATCH v3 19/21] x86/paravirt: Allow pv-calls outside paravirt.h Juergen Gross
2025-10-06 7:46 ` [PATCH v3 20/21] x86/paravirt: Specify pv_ops array in paravirt macros Juergen Gross
2025-10-06 7:46 ` [PATCH v3 21/21] x86/pvlocks: Move paravirt spinlock functions into own header Juergen Gross
2025-10-15 8:53 ` kernel test robot
2025-11-24 9:42 ` [PATCH v3 00/21] paravirt: cleanup and reorg Juergen Gross
2026-02-20 4:10 ` patchwork-bot+linux-riscv
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