1 // SPDX-License-Identifier: GPL-2.0
3 * sparse memory mappings.
6 #include <linux/slab.h>
7 #include <linux/mmzone.h>
8 #include <linux/bootmem.h>
9 #include <linux/compiler.h>
10 #include <linux/highmem.h>
11 #include <linux/export.h>
12 #include <linux/spinlock.h>
13 #include <linux/vmalloc.h>
17 #include <asm/pgalloc.h>
18 #include <asm/pgtable.h>
21 * Permanent SPARSEMEM data:
23 * 1) mem_section - memory sections, mem_map's for valid memory
25 #ifdef CONFIG_SPARSEMEM_EXTREME
26 struct mem_section **mem_section;
28 struct mem_section mem_section[NR_SECTION_ROOTS][SECTIONS_PER_ROOT]
29 ____cacheline_internodealigned_in_smp;
31 EXPORT_SYMBOL(mem_section);
33 #ifdef NODE_NOT_IN_PAGE_FLAGS
35 * If we did not store the node number in the page then we have to
36 * do a lookup in the section_to_node_table in order to find which
37 * node the page belongs to.
39 #if MAX_NUMNODES <= 256
40 static u8 section_to_node_table[NR_MEM_SECTIONS] __cacheline_aligned;
42 static u16 section_to_node_table[NR_MEM_SECTIONS] __cacheline_aligned;
45 int page_to_nid(const struct page *page)
47 return section_to_node_table[page_to_section(page)];
49 EXPORT_SYMBOL(page_to_nid);
51 static void set_section_nid(unsigned long section_nr, int nid)
53 section_to_node_table[section_nr] = nid;
55 #else /* !NODE_NOT_IN_PAGE_FLAGS */
56 static inline void set_section_nid(unsigned long section_nr, int nid)
61 #ifdef CONFIG_SPARSEMEM_EXTREME
62 static noinline struct mem_section __ref *sparse_index_alloc(int nid)
64 struct mem_section *section = NULL;
65 unsigned long array_size = SECTIONS_PER_ROOT *
66 sizeof(struct mem_section);
68 if (slab_is_available())
69 section = kzalloc_node(array_size, GFP_KERNEL, nid);
71 section = memblock_virt_alloc_node(array_size, nid);
76 static int __meminit sparse_index_init(unsigned long section_nr, int nid)
78 unsigned long root = SECTION_NR_TO_ROOT(section_nr);
79 struct mem_section *section;
81 if (mem_section[root])
84 section = sparse_index_alloc(nid);
88 mem_section[root] = section;
92 #else /* !SPARSEMEM_EXTREME */
93 static inline int sparse_index_init(unsigned long section_nr, int nid)
99 #ifdef CONFIG_SPARSEMEM_EXTREME
100 int __section_nr(struct mem_section* ms)
102 unsigned long root_nr;
103 struct mem_section *root = NULL;
105 for (root_nr = 0; root_nr < NR_SECTION_ROOTS; root_nr++) {
106 root = __nr_to_section(root_nr * SECTIONS_PER_ROOT);
110 if ((ms >= root) && (ms < (root + SECTIONS_PER_ROOT)))
116 return (root_nr * SECTIONS_PER_ROOT) + (ms - root);
119 int __section_nr(struct mem_section* ms)
121 return (int)(ms - mem_section[0]);
126 * During early boot, before section_mem_map is used for an actual
127 * mem_map, we use section_mem_map to store the section's NUMA
128 * node. This keeps us from having to use another data structure. The
129 * node information is cleared just before we store the real mem_map.
131 static inline unsigned long sparse_encode_early_nid(int nid)
133 return (nid << SECTION_NID_SHIFT);
136 static inline int sparse_early_nid(struct mem_section *section)
138 return (section->section_mem_map >> SECTION_NID_SHIFT);
141 /* Validate the physical addressing limitations of the model */
142 void __meminit mminit_validate_memmodel_limits(unsigned long *start_pfn,
143 unsigned long *end_pfn)
145 unsigned long max_sparsemem_pfn = 1UL << (MAX_PHYSMEM_BITS-PAGE_SHIFT);
148 * Sanity checks - do not allow an architecture to pass
149 * in larger pfns than the maximum scope of sparsemem:
151 if (*start_pfn > max_sparsemem_pfn) {
152 mminit_dprintk(MMINIT_WARNING, "pfnvalidation",
153 "Start of range %lu -> %lu exceeds SPARSEMEM max %lu\n",
154 *start_pfn, *end_pfn, max_sparsemem_pfn);
156 *start_pfn = max_sparsemem_pfn;
157 *end_pfn = max_sparsemem_pfn;
158 } else if (*end_pfn > max_sparsemem_pfn) {
159 mminit_dprintk(MMINIT_WARNING, "pfnvalidation",
160 "End of range %lu -> %lu exceeds SPARSEMEM max %lu\n",
161 *start_pfn, *end_pfn, max_sparsemem_pfn);
163 *end_pfn = max_sparsemem_pfn;
168 * There are a number of times that we loop over NR_MEM_SECTIONS,
169 * looking for section_present() on each. But, when we have very
170 * large physical address spaces, NR_MEM_SECTIONS can also be
171 * very large which makes the loops quite long.
173 * Keeping track of this gives us an easy way to break out of
176 int __highest_present_section_nr;
177 static void section_mark_present(struct mem_section *ms)
179 int section_nr = __section_nr(ms);
181 if (section_nr > __highest_present_section_nr)
182 __highest_present_section_nr = section_nr;
184 ms->section_mem_map |= SECTION_MARKED_PRESENT;
187 static inline int next_present_section_nr(int section_nr)
191 if (present_section_nr(section_nr))
193 } while ((section_nr < NR_MEM_SECTIONS) &&
194 (section_nr <= __highest_present_section_nr));
198 #define for_each_present_section_nr(start, section_nr) \
199 for (section_nr = next_present_section_nr(start-1); \
200 ((section_nr >= 0) && \
201 (section_nr < NR_MEM_SECTIONS) && \
202 (section_nr <= __highest_present_section_nr)); \
203 section_nr = next_present_section_nr(section_nr))
205 /* Record a memory area against a node. */
206 void __init memory_present(int nid, unsigned long start, unsigned long end)
210 #ifdef CONFIG_SPARSEMEM_EXTREME
211 if (unlikely(!mem_section)) {
212 unsigned long size, align;
214 size = sizeof(struct mem_section*) * NR_SECTION_ROOTS;
215 align = 1 << (INTERNODE_CACHE_SHIFT);
216 mem_section = memblock_virt_alloc(size, align);
220 start &= PAGE_SECTION_MASK;
221 mminit_validate_memmodel_limits(&start, &end);
222 for (pfn = start; pfn < end; pfn += PAGES_PER_SECTION) {
223 unsigned long section = pfn_to_section_nr(pfn);
224 struct mem_section *ms;
226 sparse_index_init(section, nid);
227 set_section_nid(section, nid);
229 ms = __nr_to_section(section);
230 if (!ms->section_mem_map) {
231 ms->section_mem_map = sparse_encode_early_nid(nid) |
233 section_mark_present(ms);
239 * Only used by the i386 NUMA architecures, but relatively
242 unsigned long __init node_memmap_size_bytes(int nid, unsigned long start_pfn,
243 unsigned long end_pfn)
246 unsigned long nr_pages = 0;
248 mminit_validate_memmodel_limits(&start_pfn, &end_pfn);
249 for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
250 if (nid != early_pfn_to_nid(pfn))
253 if (pfn_present(pfn))
254 nr_pages += PAGES_PER_SECTION;
257 return nr_pages * sizeof(struct page);
261 * Subtle, we encode the real pfn into the mem_map such that
262 * the identity pfn - section_mem_map will return the actual
263 * physical page frame number.
265 static unsigned long sparse_encode_mem_map(struct page *mem_map, unsigned long pnum)
267 unsigned long coded_mem_map =
268 (unsigned long)(mem_map - (section_nr_to_pfn(pnum)));
269 BUILD_BUG_ON(SECTION_MAP_LAST_BIT > (1UL<<PFN_SECTION_SHIFT));
270 BUG_ON(coded_mem_map & ~SECTION_MAP_MASK);
271 return coded_mem_map;
275 * Decode mem_map from the coded memmap
277 struct page *sparse_decode_mem_map(unsigned long coded_mem_map, unsigned long pnum)
279 /* mask off the extra low bits of information */
280 coded_mem_map &= SECTION_MAP_MASK;
281 return ((struct page *)coded_mem_map) + section_nr_to_pfn(pnum);
284 static int __meminit sparse_init_one_section(struct mem_section *ms,
285 unsigned long pnum, struct page *mem_map,
286 unsigned long *pageblock_bitmap)
288 if (!present_section(ms))
291 ms->section_mem_map &= ~SECTION_MAP_MASK;
292 ms->section_mem_map |= sparse_encode_mem_map(mem_map, pnum) |
294 ms->pageblock_flags = pageblock_bitmap;
299 unsigned long usemap_size(void)
301 return BITS_TO_LONGS(SECTION_BLOCKFLAGS_BITS) * sizeof(unsigned long);
304 #ifdef CONFIG_MEMORY_HOTPLUG
305 static unsigned long *__kmalloc_section_usemap(void)
307 return kmalloc(usemap_size(), GFP_KERNEL);
309 #endif /* CONFIG_MEMORY_HOTPLUG */
311 #ifdef CONFIG_MEMORY_HOTREMOVE
312 static unsigned long * __init
313 sparse_early_usemaps_alloc_pgdat_section(struct pglist_data *pgdat,
316 unsigned long goal, limit;
320 * A page may contain usemaps for other sections preventing the
321 * page being freed and making a section unremovable while
322 * other sections referencing the usemap remain active. Similarly,
323 * a pgdat can prevent a section being removed. If section A
324 * contains a pgdat and section B contains the usemap, both
325 * sections become inter-dependent. This allocates usemaps
326 * from the same section as the pgdat where possible to avoid
329 goal = __pa(pgdat) & (PAGE_SECTION_MASK << PAGE_SHIFT);
330 limit = goal + (1UL << PA_SECTION_SHIFT);
331 nid = early_pfn_to_nid(goal >> PAGE_SHIFT);
333 p = memblock_virt_alloc_try_nid_nopanic(size,
334 SMP_CACHE_BYTES, goal, limit,
343 static void __init check_usemap_section_nr(int nid, unsigned long *usemap)
345 unsigned long usemap_snr, pgdat_snr;
346 static unsigned long old_usemap_snr;
347 static unsigned long old_pgdat_snr;
348 struct pglist_data *pgdat = NODE_DATA(nid);
352 if (!old_usemap_snr) {
353 old_usemap_snr = NR_MEM_SECTIONS;
354 old_pgdat_snr = NR_MEM_SECTIONS;
357 usemap_snr = pfn_to_section_nr(__pa(usemap) >> PAGE_SHIFT);
358 pgdat_snr = pfn_to_section_nr(__pa(pgdat) >> PAGE_SHIFT);
359 if (usemap_snr == pgdat_snr)
362 if (old_usemap_snr == usemap_snr && old_pgdat_snr == pgdat_snr)
363 /* skip redundant message */
366 old_usemap_snr = usemap_snr;
367 old_pgdat_snr = pgdat_snr;
369 usemap_nid = sparse_early_nid(__nr_to_section(usemap_snr));
370 if (usemap_nid != nid) {
371 pr_info("node %d must be removed before remove section %ld\n",
376 * There is a circular dependency.
377 * Some platforms allow un-removable section because they will just
378 * gather other removable sections for dynamic partitioning.
379 * Just notify un-removable section's number here.
381 pr_info("Section %ld and %ld (node %d) have a circular dependency on usemap and pgdat allocations\n",
382 usemap_snr, pgdat_snr, nid);
385 static unsigned long * __init
386 sparse_early_usemaps_alloc_pgdat_section(struct pglist_data *pgdat,
389 return memblock_virt_alloc_node_nopanic(size, pgdat->node_id);
392 static void __init check_usemap_section_nr(int nid, unsigned long *usemap)
395 #endif /* CONFIG_MEMORY_HOTREMOVE */
397 static void __init sparse_early_usemaps_alloc_node(void *data,
398 unsigned long pnum_begin,
399 unsigned long pnum_end,
400 unsigned long usemap_count, int nodeid)
404 unsigned long **usemap_map = (unsigned long **)data;
405 int size = usemap_size();
407 usemap = sparse_early_usemaps_alloc_pgdat_section(NODE_DATA(nodeid),
408 size * usemap_count);
410 pr_warn("%s: allocation failed\n", __func__);
414 for (pnum = pnum_begin; pnum < pnum_end; pnum++) {
415 if (!present_section_nr(pnum))
417 usemap_map[pnum] = usemap;
419 check_usemap_section_nr(nodeid, usemap_map[pnum]);
423 #ifndef CONFIG_SPARSEMEM_VMEMMAP
424 struct page __init *sparse_mem_map_populate(unsigned long pnum, int nid)
429 map = alloc_remap(nid, sizeof(struct page) * PAGES_PER_SECTION);
433 size = PAGE_ALIGN(sizeof(struct page) * PAGES_PER_SECTION);
434 map = memblock_virt_alloc_try_nid(size,
435 PAGE_SIZE, __pa(MAX_DMA_ADDRESS),
436 BOOTMEM_ALLOC_ACCESSIBLE, nid);
439 void __init sparse_mem_maps_populate_node(struct page **map_map,
440 unsigned long pnum_begin,
441 unsigned long pnum_end,
442 unsigned long map_count, int nodeid)
446 unsigned long size = sizeof(struct page) * PAGES_PER_SECTION;
448 map = alloc_remap(nodeid, size * map_count);
450 for (pnum = pnum_begin; pnum < pnum_end; pnum++) {
451 if (!present_section_nr(pnum))
459 size = PAGE_ALIGN(size);
460 map = memblock_virt_alloc_try_nid_raw(size * map_count,
461 PAGE_SIZE, __pa(MAX_DMA_ADDRESS),
462 BOOTMEM_ALLOC_ACCESSIBLE, nodeid);
464 for (pnum = pnum_begin; pnum < pnum_end; pnum++) {
465 if (!present_section_nr(pnum))
474 for (pnum = pnum_begin; pnum < pnum_end; pnum++) {
475 struct mem_section *ms;
477 if (!present_section_nr(pnum))
479 map_map[pnum] = sparse_mem_map_populate(pnum, nodeid);
482 ms = __nr_to_section(pnum);
483 pr_err("%s: sparsemem memory map backing failed some memory will not be available\n",
485 ms->section_mem_map = 0;
488 #endif /* !CONFIG_SPARSEMEM_VMEMMAP */
490 #ifdef CONFIG_SPARSEMEM_ALLOC_MEM_MAP_TOGETHER
491 static void __init sparse_early_mem_maps_alloc_node(void *data,
492 unsigned long pnum_begin,
493 unsigned long pnum_end,
494 unsigned long map_count, int nodeid)
496 struct page **map_map = (struct page **)data;
497 sparse_mem_maps_populate_node(map_map, pnum_begin, pnum_end,
501 static struct page __init *sparse_early_mem_map_alloc(unsigned long pnum)
504 struct mem_section *ms = __nr_to_section(pnum);
505 int nid = sparse_early_nid(ms);
507 map = sparse_mem_map_populate(pnum, nid);
511 pr_err("%s: sparsemem memory map backing failed some memory will not be available\n",
513 ms->section_mem_map = 0;
518 void __weak __meminit vmemmap_populate_print_last(void)
523 * alloc_usemap_and_memmap - memory alloction for pageblock flags and vmemmap
524 * @map: usemap_map for pageblock flags or mmap_map for vmemmap
526 static void __init alloc_usemap_and_memmap(void (*alloc_func)
527 (void *, unsigned long, unsigned long,
528 unsigned long, int), void *data)
531 unsigned long map_count;
532 int nodeid_begin = 0;
533 unsigned long pnum_begin = 0;
535 for_each_present_section_nr(0, pnum) {
536 struct mem_section *ms;
538 ms = __nr_to_section(pnum);
539 nodeid_begin = sparse_early_nid(ms);
544 for_each_present_section_nr(pnum_begin + 1, pnum) {
545 struct mem_section *ms;
548 ms = __nr_to_section(pnum);
549 nodeid = sparse_early_nid(ms);
550 if (nodeid == nodeid_begin) {
554 /* ok, we need to take cake of from pnum_begin to pnum - 1*/
555 alloc_func(data, pnum_begin, pnum,
556 map_count, nodeid_begin);
557 /* new start, update count etc*/
558 nodeid_begin = nodeid;
563 alloc_func(data, pnum_begin, NR_MEM_SECTIONS,
564 map_count, nodeid_begin);
568 * Allocate the accumulated non-linear sections, allocate a mem_map
569 * for each and record the physical to section mapping.
571 void __init sparse_init(void)
575 unsigned long *usemap;
576 unsigned long **usemap_map;
578 #ifdef CONFIG_SPARSEMEM_ALLOC_MEM_MAP_TOGETHER
580 struct page **map_map;
583 /* see include/linux/mmzone.h 'struct mem_section' definition */
584 BUILD_BUG_ON(!is_power_of_2(sizeof(struct mem_section)));
586 /* Setup pageblock_order for HUGETLB_PAGE_SIZE_VARIABLE */
587 set_pageblock_order();
590 * map is using big page (aka 2M in x86 64 bit)
591 * usemap is less one page (aka 24 bytes)
592 * so alloc 2M (with 2M align) and 24 bytes in turn will
593 * make next 2M slip to one more 2M later.
594 * then in big system, the memory will have a lot of holes...
595 * here try to allocate 2M pages continuously.
597 * powerpc need to call sparse_init_one_section right after each
598 * sparse_early_mem_map_alloc, so allocate usemap_map at first.
600 size = sizeof(unsigned long *) * NR_MEM_SECTIONS;
601 usemap_map = memblock_virt_alloc(size, 0);
603 panic("can not allocate usemap_map\n");
604 alloc_usemap_and_memmap(sparse_early_usemaps_alloc_node,
607 #ifdef CONFIG_SPARSEMEM_ALLOC_MEM_MAP_TOGETHER
608 size2 = sizeof(struct page *) * NR_MEM_SECTIONS;
609 map_map = memblock_virt_alloc(size2, 0);
611 panic("can not allocate map_map\n");
612 alloc_usemap_and_memmap(sparse_early_mem_maps_alloc_node,
616 for_each_present_section_nr(0, pnum) {
617 usemap = usemap_map[pnum];
621 #ifdef CONFIG_SPARSEMEM_ALLOC_MEM_MAP_TOGETHER
624 map = sparse_early_mem_map_alloc(pnum);
629 sparse_init_one_section(__nr_to_section(pnum), pnum, map,
633 vmemmap_populate_print_last();
635 #ifdef CONFIG_SPARSEMEM_ALLOC_MEM_MAP_TOGETHER
636 memblock_free_early(__pa(map_map), size2);
638 memblock_free_early(__pa(usemap_map), size);
641 #ifdef CONFIG_MEMORY_HOTPLUG
643 /* Mark all memory sections within the pfn range as online */
644 void online_mem_sections(unsigned long start_pfn, unsigned long end_pfn)
648 for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
649 unsigned long section_nr = pfn_to_section_nr(pfn);
650 struct mem_section *ms;
652 /* onlining code should never touch invalid ranges */
653 if (WARN_ON(!valid_section_nr(section_nr)))
656 ms = __nr_to_section(section_nr);
657 ms->section_mem_map |= SECTION_IS_ONLINE;
661 #ifdef CONFIG_MEMORY_HOTREMOVE
662 /* Mark all memory sections within the pfn range as online */
663 void offline_mem_sections(unsigned long start_pfn, unsigned long end_pfn)
667 for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
668 unsigned long section_nr = pfn_to_section_nr(start_pfn);
669 struct mem_section *ms;
672 * TODO this needs some double checking. Offlining code makes
673 * sure to check pfn_valid but those checks might be just bogus
675 if (WARN_ON(!valid_section_nr(section_nr)))
678 ms = __nr_to_section(section_nr);
679 ms->section_mem_map &= ~SECTION_IS_ONLINE;
684 #ifdef CONFIG_SPARSEMEM_VMEMMAP
685 static inline struct page *kmalloc_section_memmap(unsigned long pnum, int nid)
687 /* This will make the necessary allocations eventually. */
688 return sparse_mem_map_populate(pnum, nid);
690 static void __kfree_section_memmap(struct page *memmap)
692 unsigned long start = (unsigned long)memmap;
693 unsigned long end = (unsigned long)(memmap + PAGES_PER_SECTION);
695 vmemmap_free(start, end);
697 #ifdef CONFIG_MEMORY_HOTREMOVE
698 static void free_map_bootmem(struct page *memmap)
700 unsigned long start = (unsigned long)memmap;
701 unsigned long end = (unsigned long)(memmap + PAGES_PER_SECTION);
703 vmemmap_free(start, end);
705 #endif /* CONFIG_MEMORY_HOTREMOVE */
707 static struct page *__kmalloc_section_memmap(void)
709 struct page *page, *ret;
710 unsigned long memmap_size = sizeof(struct page) * PAGES_PER_SECTION;
712 page = alloc_pages(GFP_KERNEL|__GFP_NOWARN, get_order(memmap_size));
716 ret = vmalloc(memmap_size);
722 ret = (struct page *)pfn_to_kaddr(page_to_pfn(page));
728 static inline struct page *kmalloc_section_memmap(unsigned long pnum, int nid)
730 return __kmalloc_section_memmap();
733 static void __kfree_section_memmap(struct page *memmap)
735 if (is_vmalloc_addr(memmap))
738 free_pages((unsigned long)memmap,
739 get_order(sizeof(struct page) * PAGES_PER_SECTION));
742 #ifdef CONFIG_MEMORY_HOTREMOVE
743 static void free_map_bootmem(struct page *memmap)
745 unsigned long maps_section_nr, removing_section_nr, i;
746 unsigned long magic, nr_pages;
747 struct page *page = virt_to_page(memmap);
749 nr_pages = PAGE_ALIGN(PAGES_PER_SECTION * sizeof(struct page))
752 for (i = 0; i < nr_pages; i++, page++) {
753 magic = (unsigned long) page->freelist;
755 BUG_ON(magic == NODE_INFO);
757 maps_section_nr = pfn_to_section_nr(page_to_pfn(page));
758 removing_section_nr = page_private(page);
761 * When this function is called, the removing section is
762 * logical offlined state. This means all pages are isolated
763 * from page allocator. If removing section's memmap is placed
764 * on the same section, it must not be freed.
765 * If it is freed, page allocator may allocate it which will
766 * be removed physically soon.
768 if (maps_section_nr != removing_section_nr)
769 put_page_bootmem(page);
772 #endif /* CONFIG_MEMORY_HOTREMOVE */
773 #endif /* CONFIG_SPARSEMEM_VMEMMAP */
776 * returns the number of sections whose mem_maps were properly
777 * set. If this is <=0, then that means that the passed-in
778 * map was not consumed and must be freed.
780 int __meminit sparse_add_one_section(struct pglist_data *pgdat, unsigned long start_pfn)
782 unsigned long section_nr = pfn_to_section_nr(start_pfn);
783 struct mem_section *ms;
785 unsigned long *usemap;
790 * no locking for this, because it does its own
791 * plus, it does a kmalloc
793 ret = sparse_index_init(section_nr, pgdat->node_id);
794 if (ret < 0 && ret != -EEXIST)
796 memmap = kmalloc_section_memmap(section_nr, pgdat->node_id);
799 usemap = __kmalloc_section_usemap();
801 __kfree_section_memmap(memmap);
805 pgdat_resize_lock(pgdat, &flags);
807 ms = __pfn_to_section(start_pfn);
808 if (ms->section_mem_map & SECTION_MARKED_PRESENT) {
813 memset(memmap, 0, sizeof(struct page) * PAGES_PER_SECTION);
815 section_mark_present(ms);
817 ret = sparse_init_one_section(ms, section_nr, memmap, usemap);
820 pgdat_resize_unlock(pgdat, &flags);
823 __kfree_section_memmap(memmap);
828 #ifdef CONFIG_MEMORY_HOTREMOVE
829 #ifdef CONFIG_MEMORY_FAILURE
830 static void clear_hwpoisoned_pages(struct page *memmap, int nr_pages)
837 for (i = 0; i < nr_pages; i++) {
838 if (PageHWPoison(&memmap[i])) {
839 atomic_long_sub(1, &num_poisoned_pages);
840 ClearPageHWPoison(&memmap[i]);
845 static inline void clear_hwpoisoned_pages(struct page *memmap, int nr_pages)
850 static void free_section_usemap(struct page *memmap, unsigned long *usemap)
852 struct page *usemap_page;
857 usemap_page = virt_to_page(usemap);
859 * Check to see if allocation came from hot-plug-add
861 if (PageSlab(usemap_page) || PageCompound(usemap_page)) {
864 __kfree_section_memmap(memmap);
869 * The usemap came from bootmem. This is packed with other usemaps
870 * on the section which has pgdat at boot time. Just keep it as is now.
874 free_map_bootmem(memmap);
877 void sparse_remove_one_section(struct zone *zone, struct mem_section *ms,
878 unsigned long map_offset)
880 struct page *memmap = NULL;
881 unsigned long *usemap = NULL, flags;
882 struct pglist_data *pgdat = zone->zone_pgdat;
884 pgdat_resize_lock(pgdat, &flags);
885 if (ms->section_mem_map) {
886 usemap = ms->pageblock_flags;
887 memmap = sparse_decode_mem_map(ms->section_mem_map,
889 ms->section_mem_map = 0;
890 ms->pageblock_flags = NULL;
892 pgdat_resize_unlock(pgdat, &flags);
894 clear_hwpoisoned_pages(memmap + map_offset,
895 PAGES_PER_SECTION - map_offset);
896 free_section_usemap(memmap, usemap);
898 #endif /* CONFIG_MEMORY_HOTREMOVE */
899 #endif /* CONFIG_MEMORY_HOTPLUG */