if (!mem_section[section].section_mem_map) mem_section[section].section_mem_map = SECTION_MARKED_PRESENT;
struct mem_section *ms;  sparse_index_init(section, nid);  ms = __nr_to_section(section); if (!ms->section_mem_map) ms->section_mem_map = SECTION_MARKED_PRESENT;
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 = SECTION_MARKED_PRESENT;	}}