Re: [PATCH 2/4] watchdog: introduce arch_touch_nmi_watchdog()

[Don Zickus <dzickus@redhat.com>]

On Thu, May 25, 2017 at 06:28:54PM +1000, Nicholas Piggin wrote:
> For architectures that define HAVE_NMI_WATCHDOG, instead of having
> them provide the complete touch_nmi_watchdog() function, just have
> them provide arch_touch_nmi_watchdog().
> 
> This gives the generic code more flexibility in implementing this
> function, and arch implementations don't miss out on touching the
> softlockup watchdog or other generic details.

The idea makes sense.  I don't think you can have hld_touch_nmi_watchdog
defined with arch_touch_nmi_watchdog, so I am wondering if it makes sense to
combine them somehow.  Though renaming hld_touch_nmi_watchdog to
arch_touch_nmi_watchdog sounds odd, I think it mimics the idea.

Cheers,
Don

> 
> Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
> ---
>  arch/blackfin/include/asm/nmi.h            |  2 ++
>  arch/blackfin/kernel/nmi.c                 |  2 +-
>  arch/mn10300/include/asm/nmi.h             |  2 ++
>  arch/mn10300/kernel/mn10300-watchdog-low.S |  8 ++++----
>  arch/mn10300/kernel/mn10300-watchdog.c     |  2 +-
>  arch/sparc/include/asm/nmi.h               |  1 +
>  arch/sparc/kernel/nmi.c                    |  6 ++----
>  include/linux/nmi.h                        | 26 +++++++++++++++-----------
>  kernel/watchdog_hld.c                      |  5 ++---
>  9 files changed, 30 insertions(+), 24 deletions(-)
> 
> diff --git a/arch/blackfin/include/asm/nmi.h b/arch/blackfin/include/asm/nmi.h
> index b9caac4fcfd8..6e7047ceec79 100644
> --- a/arch/blackfin/include/asm/nmi.h
> +++ b/arch/blackfin/include/asm/nmi.h
> @@ -7,6 +7,8 @@
>  #ifndef _BFIN_NMI_H_
>  #define _BFIN_NMI_H_
>  
> +void arch_touch_nmi_watchdog(void);
> +
>  #include <linux/nmi.h>
>  
>  #endif
> diff --git a/arch/blackfin/kernel/nmi.c b/arch/blackfin/kernel/nmi.c
> index 633c37083e87..1e714329fe8a 100644
> --- a/arch/blackfin/kernel/nmi.c
> +++ b/arch/blackfin/kernel/nmi.c
> @@ -190,7 +190,7 @@ static int __init init_nmi_wdt(void)
>  }
>  device_initcall(init_nmi_wdt);
>  
> -void touch_nmi_watchdog(void)
> +void arch_touch_nmi_watchdog(void)
>  {
>  	atomic_set(&nmi_touched[smp_processor_id()], 1);
>  }
> diff --git a/arch/mn10300/include/asm/nmi.h b/arch/mn10300/include/asm/nmi.h
> index f3671cbbc117..aee8aa22d9ee 100644
> --- a/arch/mn10300/include/asm/nmi.h
> +++ b/arch/mn10300/include/asm/nmi.h
> @@ -11,4 +11,6 @@
>  #ifndef _ASM_NMI_H
>  #define _ASM_NMI_H
>  
> +void arch_touch_nmi_watchdog(void);
> +
>  #endif /* _ASM_NMI_H */
> diff --git a/arch/mn10300/kernel/mn10300-watchdog-low.S b/arch/mn10300/kernel/mn10300-watchdog-low.S
> index f2f5c9cfaabd..34f8773de7d0 100644
> --- a/arch/mn10300/kernel/mn10300-watchdog-low.S
> +++ b/arch/mn10300/kernel/mn10300-watchdog-low.S
> @@ -50,9 +50,9 @@ watchdog_handler:
>  #   we can't inline it)
>  #
>  ###############################################################################
> -	.globl	touch_nmi_watchdog
> -	.type	touch_nmi_watchdog,@function
> -touch_nmi_watchdog:
> +	.globl	arch_touch_nmi_watchdog
> +	.type	arch_touch_nmi_watchdog,@function
> +arch_touch_nmi_watchdog:
>  	clr	d0
>  	clr	d1
>  	mov	watchdog_alert_counter, a0
> @@ -63,4 +63,4 @@ touch_nmi_watchdog:
>  	lne
>  	ret	[],0
>  
> -	.size	touch_nmi_watchdog,.-touch_nmi_watchdog
> +	.size	arch_touch_nmi_watchdog,.-arch_touch_nmi_watchdog
> diff --git a/arch/mn10300/kernel/mn10300-watchdog.c b/arch/mn10300/kernel/mn10300-watchdog.c
> index a2d8e6938d67..0d5641beadf5 100644
> --- a/arch/mn10300/kernel/mn10300-watchdog.c
> +++ b/arch/mn10300/kernel/mn10300-watchdog.c
> @@ -31,7 +31,7 @@ static unsigned int watchdog;
>  static unsigned int watchdog_hz = 1;
>  unsigned int watchdog_alert_counter[NR_CPUS];
>  
> -EXPORT_SYMBOL(touch_nmi_watchdog);
> +EXPORT_SYMBOL(arch_touch_nmi_watchdog);
>  
>  /*
>   * the best way to detect whether a CPU has a 'hard lockup' problem
> diff --git a/arch/sparc/include/asm/nmi.h b/arch/sparc/include/asm/nmi.h
> index 26ad2b2607c6..284eac3ffaf2 100644
> --- a/arch/sparc/include/asm/nmi.h
> +++ b/arch/sparc/include/asm/nmi.h
> @@ -7,6 +7,7 @@ void nmi_adjust_hz(unsigned int new_hz);
>  
>  extern atomic_t nmi_active;
>  
> +void arch_touch_nmi_watchdog(void);
>  void start_nmi_watchdog(void *unused);
>  void stop_nmi_watchdog(void *unused);
>  
> diff --git a/arch/sparc/kernel/nmi.c b/arch/sparc/kernel/nmi.c
> index 95e73c63c99d..048ad783ea3f 100644
> --- a/arch/sparc/kernel/nmi.c
> +++ b/arch/sparc/kernel/nmi.c
> @@ -51,7 +51,7 @@ static DEFINE_PER_CPU(unsigned int, last_irq_sum);
>  static DEFINE_PER_CPU(long, alert_counter);
>  static DEFINE_PER_CPU(int, nmi_touch);
>  
> -void touch_nmi_watchdog(void)
> +void arch_touch_nmi_watchdog(void)
>  {
>  	if (atomic_read(&nmi_active)) {
>  		int cpu;
> @@ -61,10 +61,8 @@ void touch_nmi_watchdog(void)
>  				per_cpu(nmi_touch, cpu) = 1;
>  		}
>  	}
> -
> -	touch_softlockup_watchdog();
>  }
> -EXPORT_SYMBOL(touch_nmi_watchdog);
> +EXPORT_SYMBOL(arch_touch_nmi_watchdog);
>  
>  static void die_nmi(const char *str, struct pt_regs *regs, int do_panic)
>  {
> diff --git a/include/linux/nmi.h b/include/linux/nmi.h
> index 5e2e57536d98..6ea465a842a1 100644
> --- a/include/linux/nmi.h
> +++ b/include/linux/nmi.h
> @@ -6,6 +6,9 @@
>  
>  #include <linux/sched.h>
>  #include <asm/irq.h>
> +#if defined(CONFIG_HAVE_NMI_WATCHDOG)
> +#include <asm/nmi.h>
> +#endif
>  
>  #ifdef CONFIG_LOCKUP_DETECTOR
>  extern void touch_softlockup_watchdog_sched(void);
> @@ -58,6 +61,14 @@ static inline void reset_hung_task_detector(void)
>  #define NMI_WATCHDOG_ENABLED      (1 << NMI_WATCHDOG_ENABLED_BIT)
>  #define SOFT_WATCHDOG_ENABLED     (1 << SOFT_WATCHDOG_ENABLED_BIT)
>  
> +#if defined(CONFIG_HARDLOCKUP_DETECTOR)
> +extern void hld_touch_nmi_watchdog(void);
> +extern void hardlockup_detector_disable(void);
> +#else
> +static inline void hld_touch_nmi_watchdog(void) {}
> +static inline void hardlockup_detector_disable(void) {}
> +#endif
> +
>  /**
>   * touch_nmi_watchdog - restart NMI watchdog timeout.
>   * 
> @@ -65,21 +76,14 @@ static inline void reset_hung_task_detector(void)
>   * may be used to reset the timeout - for code which intentionally
>   * disables interrupts for a long time. This call is stateless.
>   */
> -#if defined(CONFIG_HAVE_NMI_WATCHDOG) || defined(CONFIG_HARDLOCKUP_DETECTOR)
> -#include <asm/nmi.h>
> -extern void touch_nmi_watchdog(void);
> -#else
>  static inline void touch_nmi_watchdog(void)
>  {
> +#if defined(CONFIG_HAVE_NMI_WATCHDOG)
> +	arch_touch_nmi_watchdog();
> +#endif
> +	hld_touch_nmi_watchdog();
>  	touch_softlockup_watchdog();
>  }
> -#endif
> -
> -#if defined(CONFIG_HARDLOCKUP_DETECTOR)
> -extern void hardlockup_detector_disable(void);
> -#else
> -static inline void hardlockup_detector_disable(void) {}
> -#endif
>  
>  /*
>   * Create trigger_all_cpu_backtrace() out of the arch-provided
> diff --git a/kernel/watchdog_hld.c b/kernel/watchdog_hld.c
> index 54a427d1f344..e0d7a7c43fb5 100644
> --- a/kernel/watchdog_hld.c
> +++ b/kernel/watchdog_hld.c
> @@ -56,7 +56,7 @@ static int __init hardlockup_panic_setup(char *str)
>  }
>  __setup("nmi_watchdog=", hardlockup_panic_setup);
>  
> -void touch_nmi_watchdog(void)
> +void hld_touch_nmi_watchdog(void)
>  {
>  	/*
>  	 * Using __raw here because some code paths have
> @@ -66,9 +66,8 @@ void touch_nmi_watchdog(void)
>  	 * going off.
>  	 */
>  	raw_cpu_write(watchdog_nmi_touch, true);
> -	touch_softlockup_watchdog();
>  }
> -EXPORT_SYMBOL(touch_nmi_watchdog);
> +EXPORT_SYMBOL(hld_touch_nmi_watchdog);
>  
>  static struct perf_event_attr wd_hw_attr = {
>  	.type		= PERF_TYPE_HARDWARE,
> -- 
> 2.11.0
>