linux-kernel - Re: [PATCH] x86: set_highmem_pages

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Date:	Tue, 3 Mar 2009 13:15:32 +0100
From:	Ingo Molnar <mingo@...e.hu>
To:	Pekka Enberg <penberg@...helsinki.fi>
Cc:	linux-kernel@...r.kernel.org, x86@...nel.org
Subject: Re: [PATCH] x86: set_highmem_pages_init() cleanup


* Pekka Enberg <penberg@...helsinki.fi> wrote:

> From: Pekka Enberg <penberg@...helsinki.fi>
> 
> Impact: cleanup
> 
> This patch moves set_highmem_pages_init() to arch/x86/mm/highmem_32.c. The
> declaration of the function is kept in asm/numa_32.h because asm/highmem.h is
> included only CONFIG_HIGHMEM is enabled so we can't put the empty static inline
> function there.
> 
> Signed-off-by: Pekka Enberg <penberg@...helsinki.fi>
> ---
>  arch/x86/include/asm/numa_32.h |    6 +++++-
>  arch/x86/mm/highmem_32.c       |   34 ++++++++++++++++++++++++++++++++++
>  arch/x86/mm/init_32.c          |   12 ------------
>  arch/x86/mm/numa_32.c          |   26 --------------------------
>  4 files changed, 39 insertions(+), 39 deletions(-)

Applied, thanks!

One question:

> diff --git a/arch/x86/include/asm/numa_32.h b/arch/x86/include/asm/numa_32.h
> index e9f5db7..a372290 100644
> --- a/arch/x86/include/asm/numa_32.h
> +++ b/arch/x86/include/asm/numa_32.h
> @@ -4,8 +4,12 @@
>  extern int pxm_to_nid(int pxm);
>  extern void numa_remove_cpu(int cpu);
>  
> -#ifdef CONFIG_NUMA
> +#ifdef CONFIG_HIGHMEM
>  extern void set_highmem_pages_init(void);
> +#else
> +static inline void set_highmem_pages_init(void)
> +{
> +}
>  #endif
>  
>  #endif /* _ASM_X86_NUMA_32_H */
> diff --git a/arch/x86/mm/highmem_32.c b/arch/x86/mm/highmem_32.c
> index bcc079c..13a823c 100644
> --- a/arch/x86/mm/highmem_32.c
> +++ b/arch/x86/mm/highmem_32.c
> @@ -1,5 +1,6 @@
>  #include <linux/highmem.h>
>  #include <linux/module.h>
> +#include <linux/swap.h> /* for totalram_pages */
>  
>  void *kmap(struct page *page)
>  {
> @@ -156,3 +157,36 @@ EXPORT_SYMBOL(kmap);
>  EXPORT_SYMBOL(kunmap);
>  EXPORT_SYMBOL(kmap_atomic);
>  EXPORT_SYMBOL(kunmap_atomic);
> +
> +#ifdef CONFIG_NUMA
> +void __init set_highmem_pages_init(void)
> +{
> +	struct zone *zone;
> +	int nid;
> +
> +	for_each_zone(zone) {
> +		unsigned long zone_start_pfn, zone_end_pfn;
> +
> +		if (!is_highmem(zone))
> +			continue;
> +
> +		zone_start_pfn = zone->zone_start_pfn;
> +		zone_end_pfn = zone_start_pfn + zone->spanned_pages;
> +
> +		nid = zone_to_nid(zone);
> +		printk(KERN_INFO "Initializing %s for node %d (%08lx:%08lx)\n",
> +				zone->name, nid, zone_start_pfn, zone_end_pfn);
> +
> +		add_highpages_with_active_regions(nid, zone_start_pfn,
> +				 zone_end_pfn);
> +	}
> +	totalram_pages += totalhigh_pages;
> +}
> +#else
> +static void __init set_highmem_pages_init(void)
> +{
> +	add_highpages_with_active_regions(0, highstart_pfn, highend_pfn);
> +
> +	totalram_pages += totalhigh_pages;
> +}
> +#endif /* CONFIG_NUMA */

Couldnt we just wrap the !NUMA case into the NUMA case and just 
have the NUMA function present, by making for_each_zone() a 
two-entries matter and making the second entry contain:

   zone->zone_start_pfn := highstart_pfn
   zone->spanned_pages := highend_pfn-highstart_pfn 

?

	Ingo
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