linux-kernel - Re: [PATCH 1/5] numa: avoid export acpi

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Date:	Tue, 05 Feb 2013 08:56:33 +0800
From:	li guang <lig.fnst@...fujitsu.com>
To:	David Rientjes <rientjes@...gle.com>
Cc:	linux-kernel@...r.kernel.org, linux-acpi@...r.kernel.org,
	x86@...nel.org
Subject: Re: [PATCH 1/5] numa: avoid export acpi_numa variable

在 2013-02-04一的 11:31 -0800，David Rientjes写道：
> On Mon, 4 Feb 2013, liguang wrote:
> 
> > diff --git a/arch/x86/include/asm/acpi.h b/arch/x86/include/asm/acpi.h
> > index 0c44630..c4e0875 100644
> > --- a/arch/x86/include/asm/acpi.h
> > +++ b/arch/x86/include/asm/acpi.h
> > @@ -181,7 +181,8 @@ static inline void disable_acpi(void) { }
> >  #define ARCH_HAS_POWER_INIT	1
> >  
> >  #ifdef CONFIG_ACPI_NUMA
> > -extern int acpi_numa;
> > +extern void bad_srat(void);
> > +extern bool srat_disabled(void);
> 
> So anything that wants to disable acpi_numa, such as xen, must call a 
> function named bad_srat()?  That seems a little misnamed itself.

I would assume every caller have the sense of what SRAT is.
(may be a little bold assumption)

> 
> >  extern int x86_acpi_numa_init(void);
> >  #endif /* CONFIG_ACPI_NUMA */
> >  
> > diff --git a/arch/x86/mm/numa.c b/arch/x86/mm/numa.c
> > index 2d125be..92986d8 100644
> > --- a/arch/x86/mm/numa.c
> > +++ b/arch/x86/mm/numa.c
> > @@ -47,7 +47,7 @@ static __init int numa_setup(char *opt)
> >  #endif
> >  #ifdef CONFIG_ACPI_NUMA
> >  	if (!strncmp(opt, "noacpi", 6))
> > -		acpi_numa = -1;
> > +		bad_srat();
> 
> This will print an error line saying "SRAT: SRAT not used." which wasn't 
> emitted before.  I don't think that's the desire.

yes, you're right.

> 
> >  #endif
> >  	return 0;
> >  }
> > diff --git a/arch/x86/mm/srat.c b/arch/x86/mm/srat.c
> > index 4ddf497..a837c95 100644
> > --- a/arch/x86/mm/srat.c
> > +++ b/arch/x86/mm/srat.c
> > @@ -24,22 +24,22 @@
> >  #include <asm/apic.h>
> >  #include <asm/uv/uv.h>
> >  
> > -int acpi_numa __initdata;
> > +static bool acpi_numa __initdata;
> >  
> 
> You've changed this to be type bool but didn't update the existing code 
> that still does "acpi_numa = 1".

good catch!

> 
> >  static __init int setup_node(int pxm)
> >  {
> >  	return acpi_map_pxm_to_node(pxm);
> >  }
> >  
> > -static __init void bad_srat(void)
> > +void __init bad_srat(void)
> >  {
> >  	printk(KERN_ERR "SRAT: SRAT not used.\n");
> > -	acpi_numa = -1;
> > +	acpi_numa = false;
> >  }
> >  
> > -static __init inline int srat_disabled(void)
> > +bool __init srat_disabled(void)
> >  {
> > -	return acpi_numa < 0;
> > +	return acpi_numa;
> >  }
> >  
> >  /* Callback for SLIT parsing */
> > diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
> > index 138e566..94c8c70 100644
> > --- a/arch/x86/xen/enlighten.c
> > +++ b/arch/x86/xen/enlighten.c
> > @@ -1415,7 +1415,7 @@ asmlinkage void __init xen_start_kernel(void)
> >  	 * any NUMA information the kernel tries to get from ACPI will
> >  	 * be meaningless.  Prevent it from trying.
> >  	 */
> > -	acpi_numa = -1;
> > +	bad_srat();
> 
> Same as before.  It seems like you want to introduce a new function 
> specifically to disable it:
> 
> 	void acpi_numa_disable(void)
> 	{
> 		acpi_numa = false;
> 	}
> 
> and then bad_srat() should call into it?

good idea, Thanks!




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