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-rw-r--r--mm/sparse.c85
1 files changed, 85 insertions, 0 deletions
diff --git a/mm/sparse.c b/mm/sparse.c
new file mode 100644
index 000000000000..f888385b9e14
--- /dev/null
+++ b/mm/sparse.c
@@ -0,0 +1,85 @@
+/*
+ * sparse memory mappings.
+ */
+#include <linux/config.h>
+#include <linux/mm.h>
+#include <linux/mmzone.h>
+#include <linux/bootmem.h>
+#include <linux/module.h>
+#include <asm/dma.h>
+
+/*
+ * Permanent SPARSEMEM data:
+ *
+ * 1) mem_section - memory sections, mem_map's for valid memory
+ */
+struct mem_section mem_section[NR_MEM_SECTIONS];
+EXPORT_SYMBOL(mem_section);
+
+/* Record a memory area against a node. */
+void memory_present(int nid, unsigned long start, unsigned long end)
+{
+ unsigned long pfn;
+
+ start &= PAGE_SECTION_MASK;
+ for (pfn = start; pfn < end; pfn += PAGES_PER_SECTION) {
+ unsigned long section = pfn_to_section_nr(pfn);
+ if (!mem_section[section].section_mem_map)
+ mem_section[section].section_mem_map = (void *) -1;
+ }
+}
+
+/*
+ * Only used by the i386 NUMA architecures, but relatively
+ * generic code.
+ */
+unsigned long __init node_memmap_size_bytes(int nid, unsigned long start_pfn,
+ unsigned long end_pfn)
+{
+ unsigned long pfn;
+ unsigned long nr_pages = 0;
+
+ for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
+ if (nid != early_pfn_to_nid(pfn))
+ continue;
+
+ if (pfn_valid(pfn))
+ nr_pages += PAGES_PER_SECTION;
+ }
+
+ return nr_pages * sizeof(struct page);
+}
+
+/*
+ * Allocate the accumulated non-linear sections, allocate a mem_map
+ * for each and record the physical to section mapping.
+ */
+void sparse_init(void)
+{
+ unsigned long pnum;
+ struct page *map;
+ int nid;
+
+ for (pnum = 0; pnum < NR_MEM_SECTIONS; pnum++) {
+ if (!mem_section[pnum].section_mem_map)
+ continue;
+
+ nid = early_pfn_to_nid(section_nr_to_pfn(pnum));
+ map = alloc_remap(nid, sizeof(struct page) * PAGES_PER_SECTION);
+ if (!map)
+ map = alloc_bootmem_node(NODE_DATA(nid),
+ sizeof(struct page) * PAGES_PER_SECTION);
+ if (!map) {
+ mem_section[pnum].section_mem_map = 0;
+ continue;
+ }
+
+ /*
+ * Subtle, we encode the real pfn into the mem_map such that
+ * the identity pfn - section_mem_map will return the actual
+ * physical page frame number.
+ */
+ mem_section[pnum].section_mem_map = map -
+ section_nr_to_pfn(pnum);
+ }
+}