Re: [PATCH v3 6/7] mm/sparse.c: move subsection_map related codes together

[David Hildenbrand]

On 07.03.20 09:42, Baoquan He wrote:
> No functional change.
> 
> Signed-off-by: Baoquan He <bhe@xxxxxxxxxx>
> ---
>  mm/sparse.c | 134 +++++++++++++++++++++++++---------------------------
>  1 file changed, 65 insertions(+), 69 deletions(-)
> 
> diff --git a/mm/sparse.c b/mm/sparse.c
> index 0fbd79c4ad81..fde651ab8741 100644
> --- a/mm/sparse.c
> +++ b/mm/sparse.c
> @@ -244,10 +244,75 @@ void __init subsection_map_init(unsigned long pfn, unsigned long nr_pages)
>  		nr_pages -= pfns;
>  	}
>  }
> +
> +static int clear_subsection_map(unsigned long pfn, unsigned long nr_pages)
> +{
> +	DECLARE_BITMAP(map, SUBSECTIONS_PER_SECTION) = { 0 };
> +	DECLARE_BITMAP(tmp, SUBSECTIONS_PER_SECTION) = { 0 };
> +	struct mem_section *ms = __pfn_to_section(pfn);
> +	unsigned long *subsection_map = ms->usage
> +		? &ms->usage->subsection_map[0] : NULL;
> +
> +	subsection_mask_set(map, pfn, nr_pages);
> +	if (subsection_map)
> +		bitmap_and(tmp, map, subsection_map, SUBSECTIONS_PER_SECTION);
> +
> +	if (WARN(!subsection_map || !bitmap_equal(tmp, map, SUBSECTIONS_PER_SECTION),
> +				"section already deactivated (%#lx + %ld)\n",
> +				pfn, nr_pages))
> +		return -EINVAL;
> +
> +	bitmap_xor(subsection_map, map, subsection_map, SUBSECTIONS_PER_SECTION);
> +
> +	return 0;
> +}
> +
> +static bool is_subsection_map_empty(struct mem_section *ms)
> +{
> +	return bitmap_empty(&ms->usage->subsection_map[0],
> +			    SUBSECTIONS_PER_SECTION);
> +}
> +
> +static int fill_subsection_map(unsigned long pfn, unsigned long nr_pages)
> +{
> +	struct mem_section *ms = __pfn_to_section(pfn);
> +	DECLARE_BITMAP(map, SUBSECTIONS_PER_SECTION) = { 0 };
> +	unsigned long *subsection_map;
> +	int rc = 0;
> +
> +	subsection_mask_set(map, pfn, nr_pages);
> +
> +	subsection_map = &ms->usage->subsection_map[0];
> +
> +	if (bitmap_empty(map, SUBSECTIONS_PER_SECTION))
> +		rc = -EINVAL;
> +	else if (bitmap_intersects(map, subsection_map, SUBSECTIONS_PER_SECTION))
> +		rc = -EEXIST;
> +	else
> +		bitmap_or(subsection_map, map, subsection_map,
> +				SUBSECTIONS_PER_SECTION);
> +
> +	return rc;
> +}
>  #else
>  void __init subsection_map_init(unsigned long pfn, unsigned long nr_pages)
>  {
>  }
> +
> +static int clear_subsection_map(unsigned long pfn, unsigned long nr_pages)
> +{
> +	return 0;
> +}
> +
> +static bool is_subsection_map_empty(struct mem_section *ms)
> +{
> +	return true;
> +}
> +
> +static int fill_subsection_map(unsigned long pfn, unsigned long nr_pages)
> +{
> +	return 0;
> +}
>  #endif
>  
>  /* Record a memory area against a node. */
> @@ -732,46 +797,6 @@ static void free_map_bootmem(struct page *memmap)
>  }
>  #endif /* CONFIG_SPARSEMEM_VMEMMAP */
>  
> -#ifdef CONFIG_SPARSEMEM_VMEMMAP
> -static int clear_subsection_map(unsigned long pfn, unsigned long nr_pages)
> -{
> -	DECLARE_BITMAP(map, SUBSECTIONS_PER_SECTION) = { 0 };
> -	DECLARE_BITMAP(tmp, SUBSECTIONS_PER_SECTION) = { 0 };
> -	struct mem_section *ms = __pfn_to_section(pfn);
> -	unsigned long *subsection_map = ms->usage
> -		? &ms->usage->subsection_map[0] : NULL;
> -
> -	subsection_mask_set(map, pfn, nr_pages);
> -	if (subsection_map)
> -		bitmap_and(tmp, map, subsection_map, SUBSECTIONS_PER_SECTION);
> -
> -	if (WARN(!subsection_map || !bitmap_equal(tmp, map, SUBSECTIONS_PER_SECTION),
> -				"section already deactivated (%#lx + %ld)\n",
> -				pfn, nr_pages))
> -		return -EINVAL;
> -
> -	bitmap_xor(subsection_map, map, subsection_map, SUBSECTIONS_PER_SECTION);
> -
> -	return 0;
> -}
> -
> -static bool is_subsection_map_empty(struct mem_section *ms)
> -{
> -	return bitmap_empty(&ms->usage->subsection_map[0],
> -			    SUBSECTIONS_PER_SECTION);
> -}
> -#else
> -static int clear_subsection_map(unsigned long pfn, unsigned long nr_pages)
> -{
> -	return 0;
> -}
> -
> -static bool is_subsection_map_empty(struct mem_section *ms)
> -{
> -	return true;
> -}
> -#endif
> -
>  /*
>   * To deactivate a memory region, there are 3 cases to handle across
>   * two configurations (SPARSEMEM_VMEMMAP={y,n}):
> @@ -826,35 +851,6 @@ static void section_deactivate(unsigned long pfn, unsigned long nr_pages,
>  		ms->section_mem_map = (unsigned long)NULL;
>  }
>  
> -#ifdef CONFIG_SPARSEMEM_VMEMMAP
> -static int fill_subsection_map(unsigned long pfn, unsigned long nr_pages)
> -{
> -	struct mem_section *ms = __pfn_to_section(pfn);
> -	DECLARE_BITMAP(map, SUBSECTIONS_PER_SECTION) = { 0 };
> -	unsigned long *subsection_map;
> -	int rc = 0;
> -
> -	subsection_mask_set(map, pfn, nr_pages);
> -
> -	subsection_map = &ms->usage->subsection_map[0];
> -
> -	if (bitmap_empty(map, SUBSECTIONS_PER_SECTION))
> -		rc = -EINVAL;
> -	else if (bitmap_intersects(map, subsection_map, SUBSECTIONS_PER_SECTION))
> -		rc = -EEXIST;
> -	else
> -		bitmap_or(subsection_map, map, subsection_map,
> -				SUBSECTIONS_PER_SECTION);
> -
> -	return rc;
> -}
> -#else
> -static int fill_subsection_map(unsigned long pfn, unsigned long nr_pages)
> -{
> -	return 0;
> -}
> -#endif
> -
>  static struct page * __meminit section_activate(int nid, unsigned long pfn,
>  		unsigned long nr_pages, struct vmem_altmap *altmap)
>  {
> 

IMHO, we don't need this patch - but just my personal opinion. Change
itself looks good on a quick glance.

-- 
Thanks,

David / dhildenb