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];
+#ifdef CONFIG_SPARSEMEM_EXTREME
+#define SECTIONS_PER_ROOT (PAGE_SIZE / sizeof (struct mem_section))
+#else
+#define SECTIONS_PER_ROOT 1
+#endif
+
+#define SECTION_NR_TO_ROOT(sec) ((sec) / SECTIONS_PER_ROOT)
+#define NR_SECTION_ROOTS (NR_MEM_SECTIONS / SECTIONS_PER_ROOT)
+#define SECTION_ROOT_MASK (SECTIONS_PER_ROOT - 1)
+
+#ifdef CONFIG_SPARSEMEM_EXTREME
+extern struct mem_section *mem_section[NR_SECTION_ROOTS];
+#else
+extern struct mem_section mem_section[NR_SECTION_ROOTS][SECTIONS_PER_ROOT];
+#endif
+
+static inline struct mem_section *__nr_to_section(unsigned long nr)
+{
+ if (!mem_section[SECTION_NR_TO_ROOT(nr)])
+ return NULL;
+ return &mem_section[SECTION_NR_TO_ROOT(nr)][nr & SECTION_ROOT_MASK];
+}
+
+/*
+ * 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->section_mem_map & SECTION_MARKED_PRESENT));
+}
+
+static inline int section_has_mem_map(struct mem_section *section)
+{
+ return (section && (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.
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)));
}
/*
void sparse_init(void);
#else
#define sparse_init() do {} while (0)
+#define sparse_index_init(_sec, _nid) do {} while (0)
#endif /* CONFIG_SPARSEMEM */
#ifdef CONFIG_NODES_SPAN_OTHER_NODES