Re: [PATCH] x86: quiesce cpuidle code

[Keir Fraser <keir.xen@gmail.com>]

On 11/11/2011 11:12, "Jan Beulich" <JBeulich@suse.com> wrote:

> So far these messages got pointlessly (as the code in other places
> assumes symmetric configuration) emitted once per CPU. Hide the debug
> one behind opt_cpu_info, and issue the info one just once (if the code
> gets adjusted to support assymtric configurations, this would need to
> be revisited, but ideally without producing per-CPU messages again).
> 
> Signed-off-by: Jan Beulich <jbeulich@suse.com>

Acked-by: Keir Fraser <keir@xen.org>

> --- a/xen/arch/x86/acpi/cpu_idle.c
> +++ b/xen/arch/x86/acpi/cpu_idle.c
> @@ -664,6 +664,8 @@ static int acpi_processor_ffh_cstate_pro
>      unsigned int edx_part;
>      unsigned int cstate_type; /* C-state type and not ACPI C-state type */
>      unsigned int num_cstate_subtype;
> +    int ret = 0;
> +    static unsigned long printed;
>  
>      if ( c->cpuid_level < CPUID_MWAIT_LEAF )
>      {
> @@ -672,8 +674,9 @@ static int acpi_processor_ffh_cstate_pro
>      }
>  
>      cpuid(CPUID_MWAIT_LEAF, &eax, &ebx, &ecx, &edx);
> -    printk(XENLOG_DEBUG "cpuid.MWAIT[.eax=%x, .ebx=%x, .ecx=%x, .edx=%x]\n",
> -           eax, ebx, ecx, edx);
> +    if ( opt_cpu_info )
> +        printk(XENLOG_DEBUG "cpuid.MWAIT[eax=%x ebx=%x ecx=%x edx=%x]\n",
> +               eax, ebx, ecx, edx);
>  
>      /* Check whether this particular cx_type (in CST) is supported or not */
>      cstate_type = (cx->reg.address >> MWAIT_SUBSTATE_SIZE) + 1;
> @@ -681,15 +684,16 @@ static int acpi_processor_ffh_cstate_pro
>      num_cstate_subtype = edx_part & MWAIT_SUBSTATE_MASK;
>  
>      if ( num_cstate_subtype < (cx->reg.address & MWAIT_SUBSTATE_MASK) )
> -        return -EFAULT;
> -
> +        ret = -ERANGE;
>      /* mwait ecx extensions INTERRUPT_BREAK should be supported for C2/C3 */
> -    if ( !(ecx & CPUID5_ECX_EXTENSIONS_SUPPORTED) ||
> -         !(ecx & CPUID5_ECX_INTERRUPT_BREAK) )
> -        return -EFAULT;
> -
> -    printk(XENLOG_INFO "Monitor-Mwait will be used to enter C-%d state\n",
> cx->type);
> -    return 0;
> +    else if ( !(ecx & CPUID5_ECX_EXTENSIONS_SUPPORTED) ||
> +              !(ecx & CPUID5_ECX_INTERRUPT_BREAK) )
> +        ret = -ENODEV;
> +    else if ( opt_cpu_info || cx->type >= BITS_PER_LONG ||
> +              !test_and_set_bit(cx->type, &printed) )
> +        printk(XENLOG_INFO "Monitor-Mwait will be used to enter C%d state\n",
> +               cx->type);
> +    return ret;
>  }
>  
>  /*
> 
> 
> 
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