Subject: Re: [RFC PATCH V6 15/19] memory-hotplug: implement register_page_bootmem_info_section of sparse-vmemmap

From: Wen Congyang <[email-masked]>
Date: Tue, 07 Aug 2012 11:48:19 +0800

At 08/03/2012 03:49 PM, [email-masked] Wrote:
> From: Yasuaki Ishimatsu <[email-masked]>
> 
> For removing memmap region of sparse-vmemmap which is allocated bootmem,
> memmap region of sparse-vmemmap needs to be registered by get_page_bootmem().
> So the patch searches pages of virtual mapping and registers the pages by
> get_page_bootmem().
> 
> Note: register_page_bootmem_memmap() is not implemented for ia64, ppc, s390,
> and sparc.
> 
> CC: David Rientjes <[email-masked]>
> CC: Jiang Liu <[email-masked]>
> CC: Len Brown <[email-masked]>
> CC: Benjamin Herrenschmidt <[email-masked]>
> CC: Paul Mackerras <[email-masked]>
> CC: Christoph Lameter <[email-masked]>
> Cc: Minchan Kim <[email-masked]>
> CC: Andrew Morton <[email-masked]>
> CC: KOSAKI Motohiro <[email-masked]>
> CC: Wen Congyang <[email-masked]>
> Signed-off-by: Yasuaki Ishimatsu <[email-masked]>
> ---
>  arch/ia64/mm/discontig.c       |    6 ++++
>  arch/powerpc/mm/init_64.c      |    6 ++++
>  arch/s390/mm/vmem.c            |    6 ++++
>  arch/sparc/mm/init_64.c        |    6 ++++
>  arch/x86/mm/init_64.c          |   52 ++++++++++++++++++++++++++++++++++++++++
>  include/linux/memory_hotplug.h |    2 +
>  include/linux/mm.h             |    3 +-
>  mm/memory_hotplug.c            |   23 +++++++++++++++--
>  8 files changed, 100 insertions(+), 4 deletions(-)
> 
> diff --git a/arch/ia64/mm/discontig.c b/arch/ia64/mm/discontig.c
> index c641333..33943db 100644
> --- a/arch/ia64/mm/discontig.c
> +++ b/arch/ia64/mm/discontig.c
> @@ -822,4 +822,10 @@ int __meminit vmemmap_populate(struct page *start_page,
>  {
>  	return vmemmap_populate_basepages(start_page, size, node);
>  }
> +
> +void register_page_bootmem_memmap(unsigned long section_nr,
> +				  struct page *start_page, unsigned long size)
> +{
> +	/* TODO */
> +}
>  #endif
> diff --git a/arch/powerpc/mm/init_64.c b/arch/powerpc/mm/init_64.c
> index 620b7ac..3690c44 100644
> --- a/arch/powerpc/mm/init_64.c
> +++ b/arch/powerpc/mm/init_64.c
> @@ -298,5 +298,11 @@ int __meminit vmemmap_populate(struct page *start_page,
>  
>  	return 0;
>  }
> +
> +void register_page_bootmem_memmap(unsigned long section_nr,
> +				  struct page *start_page, unsigned long size)
> +{
> +	/* TODO */
> +}
>  #endif /* CONFIG_SPARSEMEM_VMEMMAP */
>  
> diff --git a/arch/s390/mm/vmem.c b/arch/s390/mm/vmem.c
> index 6f896e7..eda55cd 100644
> --- a/arch/s390/mm/vmem.c
> +++ b/arch/s390/mm/vmem.c
> @@ -227,6 +227,12 @@ out:
>  	return ret;
>  }
>  
> +void register_page_bootmem_memmap(unsigned long section_nr,
> +				  struct page *start_page, unsigned long size)
> +{
> +	/* TODO */
> +}
> +
>  /*
>   * Add memory segment to the segment list if it doesn't overlap with
>   * an already present segment.
> diff --git a/arch/sparc/mm/init_64.c b/arch/sparc/mm/init_64.c
> index 6026fdd..53f7604 100644
> --- a/arch/sparc/mm/init_64.c
> +++ b/arch/sparc/mm/init_64.c
> @@ -2059,6 +2059,12 @@ int __meminit vmemmap_populate(struct page *start, unsigned long nr, int node)
>  	}
>  	return 0;
>  }
> +
> +void register_page_bootmem_memmap(unsigned long section_nr,
> +				  struct page *start_page, unsigned long size)
> +{
> +	/* TODO */
> +}
>  #endif /* CONFIG_SPARSEMEM_VMEMMAP */
>  
>  static void prot_init_common(unsigned long page_none,
> diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
> index e0d88ba..0075592 100644
> --- a/arch/x86/mm/init_64.c
> +++ b/arch/x86/mm/init_64.c
> @@ -1138,6 +1138,58 @@ vmemmap_populate(struct page *start_page, unsigned long size, int node)
>  	return 0;
>  }
>  
> +void register_page_bootmem_memmap(unsigned long section_nr,
> +				  struct page *start_page, unsigned long size)
> +{
> +	unsigned long addr = (unsigned long)start_page;
> +	unsigned long end = (unsigned long)(start_page + size);
> +	unsigned long next;
> +	pgd_t *pgd;
> +	pud_t *pud;
> +	pmd_t *pmd;
> +
> +	for (; addr < end; addr = next) {
> +		pte_t *pte = NULL;
> +
> +		pgd = pgd_offset_k(addr);
> +		if (pgd_none(*pgd)) {
> +			next = (addr + PAGE_SIZE) & PAGE_MASK;
> +			continue;
> +		}
> +		get_page_bootmem(section_nr, pgd_page(*pgd), MIX_SECTION_INFO);
> +
> +		pud = pud_offset(pgd, addr);
> +		if (pud_none(*pud)) {
> +			next = (addr + PAGE_SIZE) & PAGE_MASK;
> +			continue;
> +		}
> +		get_page_bootmem(section_nr, pud_page(*pud), MIX_SECTION_INFO);
> +
> +		if (!cpu_has_pse) {
> +			next = (addr + PAGE_SIZE) & PAGE_MASK;
> +			pmd = pmd_offset(pud, addr);
> +			if (pmd_none(*pmd))
> +				continue;
> +			get_page_bootmem(section_nr, pmd_page(*pmd),
> +					 MIX_SECTION_INFO);
> +
> +			pte = pte_offset_kernel(pmd, addr);
> +			if (pte_none(*pte))
> +				continue;
> +			get_page_bootmem(section_nr, pte_page(*pte),
> +					 SECTION_INFO);
> +		} else {
> +			next = pmd_addr_end(addr, end);
> +
> +			pmd = pmd_offset(pud, addr);
> +			if (pmd_none(*pmd))
> +				continue;
> +			get_page_bootmem(section_nr, pmd_page(*pmd),
> +					 SECTION_INFO);
> +		}
> +	}
> +}
> +
>  void __meminit vmemmap_populate_print_last(void)
>  {
>  	if (p_start) {
> diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h
> index 1133e63..2d18235 100644
> --- a/include/linux/memory_hotplug.h
> +++ b/include/linux/memory_hotplug.h
> @@ -164,6 +164,8 @@ static inline void arch_refresh_nodedata(int nid, pg_data_t *pgdat)
>  
>  extern void register_page_bootmem_info_node(struct pglist_data *pgdat);
>  extern void put_page_bootmem(struct page *page);
> +extern void get_page_bootmem(unsigned long ingo, struct page *page,
> +			     unsigned long type);
>  
>  /*
>   * Lock for memory hotplug guarantees 1) all callbacks for memory hotplug
> diff --git a/include/linux/mm.h b/include/linux/mm.h
> index 311be90..c607913 100644
> --- a/include/linux/mm.h
> +++ b/include/linux/mm.h
> @@ -1618,7 +1618,8 @@ int vmemmap_populate_basepages(struct page *start_page,
>  						unsigned long pages, int node);
>  int vmemmap_populate(struct page *start_page, unsigned long pages, int node);
>  void vmemmap_populate_print_last(void);
> -
> +void register_page_bootmem_memmap(unsigned long section_nr, struct page *map,
> +				  unsigned long size);
>  
>  enum mf_flags {
>  	MF_COUNT_INCREASED = 1 << 0,
> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
> index 3a264a5..4589f5b 100644
> --- a/mm/memory_hotplug.c
> +++ b/mm/memory_hotplug.c
> @@ -91,8 +91,8 @@ static void release_memory_resource(struct resource *res)
>  }
>  
>  #ifdef CONFIG_MEMORY_HOTPLUG_SPARSE
> -static void get_page_bootmem(unsigned long info,  struct page *page,
> -			     unsigned long type)
> +void get_page_bootmem(unsigned long info,  struct page *page,
> +		      unsigned long type)
>  {
>  	unsigned long page_type;
>  
> @@ -164,8 +164,25 @@ static void register_page_bootmem_info_section(unsigned long start_pfn)
>  
>  }
>  #else
> -static inline void register_page_bootmem_info_section(unsigned long start_pfn)
> +static void register_page_bootmem_info_section(unsigned long start_pfn)
>  {
> +	unsigned long mapsize, section_nr;
> +	struct mem_section *ms;
> +	struct page *page, *memmap;
> +
> +	if (!pfn_valid(start_pfn))
> +		return;
> +
> +	section_nr = pfn_to_section_nr(start_pfn);
> +	ms = __nr_to_section(section_nr);
> +
> +	memmap = sparse_decode_mem_map(ms->section_mem_map, section_nr);
> +
> +	page = virt_to_page(memmap);
> +	mapsize = sizeof(struct page) * PAGES_PER_SECTION;
> +	mapsize = PAGE_ALIGN(mapsize) >> PAGE_SHIFT;
> +
> +	register_page_bootmem_memmap(section_nr, memmap, PAGES_PER_SECTION);

You only handle memmap here. I think usemap should be also handled here.

Thanks
Wen Congyang

>  }
>  #endif