On 02.12.20 12:57, Frederic Weisbecker wrote:
> s390 has its own version of IRQ entry accounting because it doesn't
> account the idle time the same way the other architectures do. Only
> the actual idle sleep time is accounted as idle time, the rest of the
> idle task execution is accounted as system time.
>
> Make the generic IRQ entry accounting aware of architectures that have
> their own way of accounting idle time and convert s390 to use it.
>
> This prepares s390 to get involved in further consolidations of IRQ
> time accounting.
>
> Signed-off-by: Frederic Weisbecker <frede...@kernel.org>
> Cc: Peter Zijlstra <pet...@infradead.org>
> Cc: Tony Luck <tony.l...@intel.com>
> Cc: Fenghua Yu <fenghua...@intel.com>
> Cc: Michael Ellerman <m...@ellerman.id.au>
> Cc: Benjamin Herrenschmidt <b...@kernel.crashing.org>
> Cc: Paul Mackerras <pau...@samba.org>
> Cc: Heiko Carstens <h...@linux.ibm.com>
> Cc: Vasily Gorbik <g...@linux.ibm.com>
> Cc: Christian Borntraeger <borntrae...@de.ibm.com>
As far as I can tel,l this patch should be a no-op for s390 function-wise.
Acked-by: Christian Borntraeger <borntrae...@de.ibm.com>
> ---
> arch/Kconfig | 7 ++++++-
> arch/s390/Kconfig | 1 +
> arch/s390/include/asm/vtime.h | 1 -
> arch/s390/kernel/vtime.c | 4 ----
> kernel/sched/cputime.c | 13 ++-----------
> 5 files changed, 9 insertions(+), 17 deletions(-)
>
> diff --git a/arch/Kconfig b/arch/Kconfig
> index 56b6ccc0e32d..0f151b49c7b7 100644
> --- a/arch/Kconfig
> +++ b/arch/Kconfig
> @@ -627,6 +627,12 @@ config HAVE_TIF_NOHZ
> config HAVE_VIRT_CPU_ACCOUNTING
> bool
>
> +config HAVE_VIRT_CPU_ACCOUNTING_IDLE
> + bool
> + help
> + Architecture has its own way to account idle CPU time and therefore
> + doesn't implement vtime_account_idle().
> +
> config ARCH_HAS_SCALED_CPUTIME
> bool
>
> @@ -641,7 +647,6 @@ config HAVE_VIRT_CPU_ACCOUNTING_GEN
> some 32-bit arches may require multiple accesses, so proper
> locking is needed to protect against concurrent accesses.
>
> -
> config HAVE_IRQ_TIME_ACCOUNTING
> bool
> help
> diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
> index 4a2a12be04c9..6f1fdcd3b5db 100644
> --- a/arch/s390/Kconfig
> +++ b/arch/s390/Kconfig
> @@ -181,6 +181,7 @@ config S390
> select HAVE_RSEQ
> select HAVE_SYSCALL_TRACEPOINTS
> select HAVE_VIRT_CPU_ACCOUNTING
> + select HAVE_VIRT_CPU_ACCOUNTING_IDLE
> select IOMMU_HELPER if PCI
> select IOMMU_SUPPORT if PCI
> select MODULES_USE_ELF_RELA
> diff --git a/arch/s390/include/asm/vtime.h b/arch/s390/include/asm/vtime.h
> index 3622d4ebc73a..fac6a67988eb 100644
> --- a/arch/s390/include/asm/vtime.h
> +++ b/arch/s390/include/asm/vtime.h
> @@ -2,7 +2,6 @@
> #ifndef _S390_VTIME_H
> #define _S390_VTIME_H
>
> -#define __ARCH_HAS_VTIME_ACCOUNT
> #define __ARCH_HAS_VTIME_TASK_SWITCH
>
> #endif /* _S390_VTIME_H */
> diff --git a/arch/s390/kernel/vtime.c b/arch/s390/kernel/vtime.c
> index f9f2a11958a5..ebd8e5655789 100644
> --- a/arch/s390/kernel/vtime.c
> +++ b/arch/s390/kernel/vtime.c
> @@ -247,10 +247,6 @@ void vtime_account_kernel(struct task_struct *tsk)
> }
> EXPORT_SYMBOL_GPL(vtime_account_kernel);
>
> -void vtime_account_irq_enter(struct task_struct *tsk)
> -__attribute__((alias("vtime_account_kernel")));
> -
> -
> /*
> * Sorted add to a list. List is linear searched until first bigger
> * element is found.
> diff --git a/kernel/sched/cputime.c b/kernel/sched/cputime.c
> index 61ce9f9bf0a3..2783162542b1 100644
> --- a/kernel/sched/cputime.c
> +++ b/kernel/sched/cputime.c
> @@ -417,23 +417,14 @@ void vtime_task_switch(struct task_struct *prev)
> }
> # endif
>
> -/*
> - * Archs that account the whole time spent in the idle task
> - * (outside irq) as idle time can rely on this and just implement
> - * vtime_account_kernel() and vtime_account_idle(). Archs that
> - * have other meaning of the idle time (s390 only includes the
> - * time spent by the CPU when it's in low power mode) must override
> - * vtime_account().
> - */
> -#ifndef __ARCH_HAS_VTIME_ACCOUNT
> void vtime_account_irq_enter(struct task_struct *tsk)
> {
> - if (!in_interrupt() && is_idle_task(tsk))
> + if (!IS_ENABLED(CONFIG_HAVE_VIRT_CPU_ACCOUNTING_IDLE) &&
> + !in_interrupt() && is_idle_task(tsk))
> vtime_account_idle(tsk);
> else
> vtime_account_kernel(tsk);
> }
> -#endif /* __ARCH_HAS_VTIME_ACCOUNT */
>
> void cputime_adjust(struct task_cputime *curr, struct prev_cputime *prev,
> u64 *ut, u64 *st)
>
