diff options
Diffstat (limited to 'include/linux/mmzone.h')
| -rw-r--r-- | include/linux/mmzone.h | 56 |
1 files changed, 51 insertions, 5 deletions
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index 746b57e3d37..6c90461ed99 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -476,11 +476,56 @@ extern struct pglist_data contig_page_data; struct page; struct mem_section { - struct page *section_mem_map; + /* + * This is, logically, a pointer to an array of struct + * pages. However, it is stored with some other magic. + * (see sparse.c::sparse_init_one_section()) + * + * Making it a UL at least makes someone do a cast + * before using it wrong. + */ + unsigned long section_mem_map; }; extern struct mem_section mem_section[NR_MEM_SECTIONS]; +static inline struct mem_section *__nr_to_section(unsigned long nr) +{ + return &mem_section[nr]; +} + +/* + * We use the lower bits of the mem_map pointer to store + * a little bit of information. There should be at least + * 3 bits here due to 32-bit alignment. + */ +#define SECTION_MARKED_PRESENT (1UL<<0) +#define SECTION_HAS_MEM_MAP (1UL<<1) +#define SECTION_MAP_LAST_BIT (1UL<<2) +#define SECTION_MAP_MASK (~(SECTION_MAP_LAST_BIT-1)) + +static inline struct page *__section_mem_map_addr(struct mem_section *section) +{ + unsigned long map = section->section_mem_map; + map &= SECTION_MAP_MASK; + return (struct page *)map; +} + +static inline int valid_section(struct mem_section *section) +{ + return (section->section_mem_map & SECTION_MARKED_PRESENT); +} + +static inline int section_has_mem_map(struct mem_section *section) +{ + return (section->section_mem_map & SECTION_HAS_MEM_MAP); +} + +static inline int valid_section_nr(unsigned long nr) +{ + return valid_section(__nr_to_section(nr)); +} + /* * Given a kernel address, find the home node of the underlying memory. */ @@ -488,24 +533,25 @@ extern struct mem_section mem_section[NR_MEM_SECTIONS]; static inline struct mem_section *__pfn_to_section(unsigned long pfn) { - return &mem_section[pfn_to_section_nr(pfn)]; + return __nr_to_section(pfn_to_section_nr(pfn)); } #define pfn_to_page(pfn) \ ({ \ unsigned long __pfn = (pfn); \ - __pfn_to_section(__pfn)->section_mem_map + __pfn; \ + __section_mem_map_addr(__pfn_to_section(__pfn)) + __pfn; \ }) #define page_to_pfn(page) \ ({ \ - page - mem_section[page_to_section(page)].section_mem_map; \ + page - __section_mem_map_addr(__nr_to_section( \ + page_to_section(page))); \ }) static inline int pfn_valid(unsigned long pfn) { if (pfn_to_section_nr(pfn) >= NR_MEM_SECTIONS) return 0; - return mem_section[pfn_to_section_nr(pfn)].section_mem_map != 0; + return valid_section(__nr_to_section(pfn_to_section_nr(pfn))); } /* |