// SPDX-License-Identifier: GPL-2.0 /* * sparse memory mappings. */ #include <linux/mm.h> #include <linux/slab.h> #include <linux/mmzone.h> #include <linux/memblock.h> #include <linux/compiler.h> #include <linux/highmem.h> #include <linux/export.h> #include <linux/spinlock.h> #include <linux/vmalloc.h> #include <linux/swap.h> #include <linux/swapops.h> #include <linux/bootmem_info.h> #include "internal.h" #include <asm/dma.h> /* * Permanent SPARSEMEM data: * * 1) mem_section - memory sections, mem_map's for valid memory */ #ifdef CONFIG_SPARSEMEM_EXTREME struct mem_section **mem_section; #else struct mem_section mem_section[NR_SECTION_ROOTS][SECTIONS_PER_ROOT] ____cacheline_internodealigned_in_smp; #endif EXPORT_SYMBOL(mem_section); #ifdef NODE_NOT_IN_PAGE_FLAGS /* * If we did not store the node number in the page then we have to * do a lookup in the section_to_node_table in order to find which * node the page belongs to. */ #if MAX_NUMNODES <= 256 static u8 section_to_node_table[NR_MEM_SECTIONS] __cacheline_aligned; #else static u16 section_to_node_table[NR_MEM_SECTIONS] __cacheline_aligned; #endif int page_to_nid(const struct page *page) { return section_to_node_table[page_to_section(page)]; } EXPORT_SYMBOL(page_to_nid); static void set_section_nid(unsigned long section_nr, int nid) { section_to_node_table[section_nr] = nid; } #else /* !NODE_NOT_IN_PAGE_FLAGS */ static inline void set_section_nid(unsigned long section_nr, int nid) { } #endif #ifdef CONFIG_SPARSEMEM_EXTREME static noinline struct mem_section __ref *sparse_index_alloc(int nid) { struct mem_section *section = NULL; unsigned long array_size = SECTIONS_PER_ROOT * sizeof(struct mem_section); if (slab_is_available()) { section = kzalloc_node(array_size, GFP_KERNEL, nid); } else { section = memblock_alloc_node(array_size, SMP_CACHE_BYTES, nid); if (!section) panic("%s: Failed to allocate %lu bytes nid=%d\n", __func__, array_size, nid); } return section; } static int __meminit sparse_index_init(unsigned long section_nr, int nid) { unsigned long root = SECTION_NR_TO_ROOT(section_nr); struct mem_section *section; /* * An existing section is possible in the sub-section hotplug * case. First hot-add instantiates, follow-on hot-add reuses * the existing section. * * The mem_hotplug_lock resolves the apparent race below. */ if (mem_section[root]) return 0; section = sparse_index_alloc(nid); if (!section) return -ENOMEM; mem_section[root] = section; return 0; } #else /* !SPARSEMEM_EXTREME */ static inline int sparse_index_init(unsigned long section_nr, int nid) { return 0; } #endif /* * During early boot, before section_mem_map is used for an actual * mem_map, we use section_mem_map to store the section's NUMA * node. This keeps us from having to use another data structure. The * node information is cleared just before we store the real mem_map. */ static inline unsigned long sparse_encode_early_nid(int nid) { return ((unsigned long)nid << SECTION_NID_SHIFT); } static inline int sparse_early_nid(struct mem_section *section) { return (section->section_mem_map >> SECTION_NID_SHIFT); } /* Validate the physical addressing limitations of the model */ static void __meminit mminit_validate_memmodel_limits(unsigned long *start_pfn, unsigned long *end_pfn) { unsigned long max_sparsemem_pfn = 1UL << (MAX_PHYSMEM_BITS-PAGE_SHIFT); /* * Sanity checks - do not allow an architecture to pass * in larger pfns than the maximum scope of sparsemem: */ if (*start_pfn > max_sparsemem_pfn) { mminit_dprintk(MMINIT_WARNING, "pfnvalidation", "Start of range %lu -> %lu exceeds SPARSEMEM max %lu\n", *start_pfn, *end_pfn, max_sparsemem_pfn); WARN_ON_ONCE(1); *start_pfn = max_sparsemem_pfn; *end_pfn = max_sparsemem_pfn; } else if (*end_pfn > max_sparsemem_pfn) { mminit_dprintk(MMINIT_WARNING, "pfnvalidation", "End of range %lu -> %lu exceeds SPARSEMEM max %lu\n", *start_pfn, *end_pfn, max_sparsemem_pfn); WARN_ON_ONCE(1); *end_pfn = max_sparsemem_pfn; } } /* * There are a number of times that we loop over NR_MEM_SECTIONS, * looking for section_present() on each. But, when we have very * large physical address spaces, NR_MEM_SECTIONS can also be * very large which makes the loops quite long. * * Keeping track of this gives us an easy way to break out of * those loops early. */ unsigned long __highest_present_section_nr; static void __section_mark_present(struct mem_section *ms, unsigned long section_nr) { if (section_nr > __highest_present_section_nr) __highest_present_section_nr = section_nr; ms->section_mem_map |= SECTION_MARKED_PRESENT; } #define for_each_present_section_nr(start, section_nr) \ for (section_nr = next_present_section_nr(start-1); \ ((section_nr != -1) && \ (section_nr <= __highest_present_section_nr)); \ section_nr = next_present_section_nr(section_nr)) static inline unsigned long first_present_section_nr(void) { return next_present_section_nr(-1); } #ifdef CONFIG_SPARSEMEM_VMEMMAP static void subsection_mask_set(unsigned long *map, unsigned long pfn, unsigned long nr_pages) { int idx = subsection_map_index(pfn); int end = subsection_map_index(pfn + nr_pages - 1); bitmap_set(map, idx, end - idx + 1); } void __init subsection_map_init(unsigned long pfn, unsigned long nr_pages) { int end_sec = pfn_to_section_nr(pfn + nr_pages - 1); unsigned long nr, start_sec = pfn_to_section_nr(pfn); if (!nr_pages) return; for (nr = start_sec; nr <= end_sec; nr++) { struct mem_section *ms; unsigned long pfns; pfns = min(nr_pages, PAGES_PER_SECTION - (pfn & ~PAGE_SECTION_MASK)); ms = __nr_to_section(nr); subsection_mask_set(ms->usage->subsection_map, pfn, pfns); pr_debug("%s: sec: %lu pfns: %lu set(%d, %d)\n", __func__, nr, pfns, subsection_map_index(pfn), subsection_map_index(pfn + pfns - 1)); pfn += pfns; nr_pages -= pfns; } } #else void __init subsection_map_init(unsigned long pfn, unsigned long nr_pages) { } #endif /* Record a memory area against a node. */ static void __init memory_present(int nid, unsigned long start, unsigned long end) { unsigned long pfn; #ifdef CONFIG_SPARSEMEM_EXTREME if (unlikely(!mem_section)) { unsigned long size, align; size = sizeof(struct mem_section *) * NR_SECTION_ROOTS; align = 1 << (INTERNODE_CACHE_SHIFT); mem_section = memblock_alloc(size, align); if (!mem_section) panic("%s: Failed to allocate %lu bytes align=0x%lx\n", __func__, size, align); } #endif start &= PAGE_SECTION_MASK; mminit_validate_memmodel_limits(&start, &end); for (pfn = start; pfn < end; pfn += PAGES_PER_SECTION) { unsigned long section = pfn_to_section_nr(pfn); struct mem_section *ms; sparse_index_init(section, nid); set_section_nid(section, nid); ms = __nr_to_section(section); if (!ms->section_mem_map) { ms->section_mem_map = sparse_encode_early_nid(nid) | SECTION_IS_ONLINE; __section_mark_present(ms, section); } } } /* * Mark all memblocks as present using memory_present(). * This is a convenience function that is useful to mark all of the systems * memory as present during initialization. */ static void __init memblocks_present(void) { unsigned long start, end; int i, nid; for_each_mem_pfn_range(i, MAX_NUMNODES, &start, &end, &nid) memory_present(nid, start, end); } /* * 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. */ static unsigned long sparse_encode_mem_map(struct page *mem_map, unsigned long pnum) { unsigned long coded_mem_map = (unsigned long)(mem_map - (section_nr_to_pfn(pnum))); BUILD_BUG_ON(SECTION_MAP_LAST_BIT > (1UL<<PFN_SECTION_SHIFT)); BUG_ON(coded_mem_map & ~SECTION_MAP_MASK); return coded_mem_map; } #ifdef CONFIG_MEMORY_HOTPLUG /* * Decode mem_map from the coded memmap */ struct page *sparse_decode_mem_map(unsigned long coded_mem_map, unsigned long pnum) { /* mask off the extra low bits of information */ coded_mem_map &= SECTION_MAP_MASK; return ((struct page *)coded_mem_map) + section_nr_to_pfn(pnum); } #endif /* CONFIG_MEMORY_HOTPLUG */ static void __meminit sparse_init_one_section(struct mem_section *ms, unsigned long pnum, struct page *mem_map, struct mem_section_usage *usage, unsigned long flags) { ms->section_mem_map &= ~SECTION_MAP_MASK; ms->section_mem_map |= sparse_encode_mem_map(mem_map, pnum) | SECTION_HAS_MEM_MAP | flags; ms->usage = usage; } static unsigned long usemap_size(void) { return BITS_TO_LONGS(SECTION_BLOCKFLAGS_BITS) * sizeof(unsigned long); } size_t mem_section_usage_size(void) { return sizeof(struct mem_section_usage) + usemap_size(); } static inline phys_addr_t pgdat_to_phys(struct pglist_data *pgdat) { #ifndef CONFIG_NUMA VM_BUG_ON(pgdat != &contig_page_data); return __pa_symbol(&contig_page_data); #else return __pa(pgdat); #endif } #ifdef CONFIG_MEMORY_HOTREMOVE static struct mem_section_usage * __init sparse_early_usemaps_alloc_pgdat_section(struct pglist_data *pgdat, unsigned long size) { struct mem_section_usage *usage; unsigned long goal, limit; int nid; /* * A page may contain usemaps for other sections preventing the * page being freed and making a section unremovable while * other sections referencing the usemap remain active. Similarly, * a pgdat can prevent a section being removed. If section A * contains a pgdat and section B contains the usemap, both * sections become inter-dependent. This allocates usemaps * from the same section as the pgdat where possible to avoid * this problem. */ goal = pgdat_to_phys(pgdat) & (PAGE_SECTION_MASK << PAGE_SHIFT); limit = goal + (1UL << PA_SECTION_SHIFT); nid = early_pfn_to_nid(goal >> PAGE_SHIFT); again: usage = memblock_alloc_try_nid(size, SMP_CACHE_BYTES, goal, limit, nid); if (!usage && limit) { limit = 0; goto again; } return usage; } static void __init check_usemap_section_nr(int nid, struct mem_section_usage *usage) { unsigned long usemap_snr, pgdat_snr; static unsigned long old_usemap_snr; static unsigned long old_pgdat_snr; struct pglist_data *pgdat = NODE_DATA(nid); int usemap_nid; /* First call */ if (!old_usemap_snr) { old_usemap_snr = NR_MEM_SECTIONS; old_pgdat_snr = NR_MEM_SECTIONS; } usemap_snr = pfn_to_section_nr(__pa(usage) >> PAGE_SHIFT); pgdat_snr = pfn_to_section_nr(pgdat_to_phys(pgdat) >> PAGE_SHIFT); if (usemap_snr == pgdat_snr) return; if (old_usemap_snr == usemap_snr && old_pgdat_snr == pgdat_snr) /* skip redundant message */ return; old_usemap_snr = usemap_snr; old_pgdat_snr = pgdat_snr; usemap_nid = sparse_early_nid(__nr_to_section(usemap_snr)); if (usemap_nid != nid) { pr_info("node %d must be removed before remove section %ld\n", nid, usemap_snr); return; } /* * There is a circular dependency. * Some platforms allow un-removable section because they will just * gather other removable sections for dynamic partitioning. * Just notify un-removable section's number here. */ pr_info("Section %ld and %ld (node %d) have a circular dependency on usemap and pgdat allocations\n", usemap_snr, pgdat_snr, nid); } #else static struct mem_section_usage * __init sparse_early_usemaps_alloc_pgdat_section(struct pglist_data *pgdat, unsigned long size) { return memblock_alloc_node(size, SMP_CACHE_BYTES, pgdat->node_id); } static void __init check_usemap_section_nr(int nid, struct mem_section_usage *usage) { } #endif /* CONFIG_MEMORY_HOTREMOVE */ #ifdef CONFIG_SPARSEMEM_VMEMMAP static unsigned long __init section_map_size(void) { return ALIGN(sizeof(struct page) * PAGES_PER_SECTION, PMD_SIZE); } #else static unsigned long __init section_map_size(void) { return PAGE_ALIGN(sizeof(struct page) * PAGES_PER_SECTION); } struct page __init *__populate_section_memmap(unsigned long pfn, unsigned long nr_pages, int nid, struct vmem_altmap *altmap, struct dev_pagemap *pgmap) { unsigned long size = section_map_size(); struct page *map = sparse_buffer_alloc(size); phys_addr_t addr = __pa(MAX_DMA_ADDRESS); if (map) return map; map = memmap_alloc(size, size, addr, nid, false); if (!map) panic("%s: Failed to allocate %lu bytes align=0x%lx nid=%d from=%pa\n", __func__, size, PAGE_SIZE, nid, &addr); return map; } #endif /* !CONFIG_SPARSEMEM_VMEMMAP */ static void *sparsemap_buf __meminitdata; static void *sparsemap_buf_end __meminitdata; static inline void __meminit sparse_buffer_free(unsigned long size) { WARN_ON(!sparsemap_buf || size == 0); memblock_free(sparsemap_buf, size); } static void __init sparse_buffer_init(unsigned long size, int nid) { phys_addr_t addr = __pa(MAX_DMA_ADDRESS); WARN_ON(sparsemap_buf); /* forgot to call sparse_buffer_fini()? */ /* * Pre-allocated buffer is mainly used by __populate_section_memmap * and we want it to be properly aligned to the section size - this is * especially the case for VMEMMAP which maps memmap to PMDs */ sparsemap_buf = memmap_alloc(size, section_map_size(), addr, nid, true); sparsemap_buf_end = sparsemap_buf + size; } static void __init sparse_buffer_fini(void) { unsigned long size = sparsemap_buf_end - sparsemap_buf; if (sparsemap_buf && size > 0) sparse_buffer_free(size); sparsemap_buf = NULL; } void * __meminit sparse_buffer_alloc(unsigned long size) { void *ptr = NULL; if (sparsemap_buf) { ptr = (void *) roundup((unsigned long)sparsemap_buf, size); if (ptr + size > sparsemap_buf_end) ptr = NULL; else { /* Free redundant aligned space */ if ((unsigned long)(ptr - sparsemap_buf) > 0) sparse_buffer_free((unsigned long)(ptr - sparsemap_buf)); sparsemap_buf = ptr + size; } } return ptr; } void __weak __meminit vmemmap_populate_print_last(void) { } /* * Initialize sparse on a specific node. The node spans [pnum_begin, pnum_end) * And number of present sections in this node is map_count. */ static void __init sparse_init_nid(int nid, unsigned long pnum_begin, unsigned long pnum_end, unsigned long map_count) { struct mem_section_usage *usage; unsigned long pnum; struct page *map; usage = sparse_early_usemaps_alloc_pgdat_section(NODE_DATA(nid), mem_section_usage_size() * map_count); if (!usage) { pr_err("%s: node[%d] usemap allocation failed", __func__, nid); goto failed; } sparse_buffer_init(map_count * section_map_size(), nid); for_each_present_section_nr(pnum_begin, pnum) { unsigned long pfn = section_nr_to_pfn(pnum); if (pnum >= pnum_end) break; map = __populate_section_memmap(pfn, PAGES_PER_SECTION, nid, NULL, NULL); if (!map) { pr_err("%s: node[%d] memory map backing failed. Some memory will not be available.", __func__, nid); pnum_begin = pnum; sparse_buffer_fini(); goto failed; } check_usemap_section_nr(nid, usage); sparse_init_one_section(__nr_to_section(pnum), pnum, map, usage, SECTION_IS_EARLY); usage = (void *) usage + mem_section_usage_size(); } sparse_buffer_fini(); return; failed: /* We failed to allocate, mark all the following pnums as not present */ for_each_present_section_nr(pnum_begin, pnum) { struct mem_section *ms; if (pnum >= pnum_end) break; ms = __nr_to_section(pnum); ms->section_mem_map = 0; } } /* * Allocate the accumulated non-linear sections, allocate a mem_map * for each and record the physical to section mapping. */ void __init sparse_init(void) { unsigned long pnum_end, pnum_begin, map_count = 1; int nid_begin; memblocks_present(); pnum_begin = first_present_section_nr(); nid_begin = sparse_early_nid(__nr_to_section(pnum_begin)); /* Setup pageblock_order for HUGETLB_PAGE_SIZE_VARIABLE */ set_pageblock_order(); for_each_present_section_nr(pnum_begin + 1, pnum_end) { int nid = sparse_early_nid(__nr_to_section(pnum_end)); if (nid == nid_begin) { map_count++; continue; } /* Init node with sections in range [pnum_begin, pnum_end) */ sparse_init_nid(nid_begin, pnum_begin, pnum_end, map_count); nid_begin = nid; pnum_begin = pnum_end; map_count = 1; } /* cover the last node */ sparse_init_nid(nid_begin, pnum_begin, pnum_end, map_count); vmemmap_populate_print_last(); } #ifdef CONFIG_MEMORY_HOTPLUG /* Mark all memory sections within the pfn range as online */ void online_mem_sections(unsigned long start_pfn, unsigned long end_pfn) { unsigned long pfn; for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) { unsigned long section_nr = pfn_to_section_nr(pfn); struct mem_section *ms; /* onlining code should never touch invalid ranges */ if (WARN_ON(!valid_section_nr(section_nr))) continue; ms = __nr_to_section(section_nr); ms->section_mem_map |= SECTION_IS_ONLINE; } } /* Mark all memory sections within the pfn range as offline */ void offline_mem_sections(unsigned long start_pfn, unsigned long end_pfn) { unsigned long pfn; for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) { unsigned long section_nr = pfn_to_section_nr(pfn); struct mem_section *ms; /* * TODO this needs some double checking. Offlining code makes * sure to check pfn_valid but those checks might be just bogus */ if (WARN_ON(!valid_section_nr(section_nr))) continue; ms = __nr_to_section(section_nr); ms->section_mem_map &= ~SECTION_IS_ONLINE; } } #ifdef CONFIG_SPARSEMEM_VMEMMAP static struct page * __meminit populate_section_memmap(unsigned long pfn, unsigned long nr_pages, int nid, struct vmem_altmap *altmap, struct dev_pagemap *pgmap) { return __populate_section_memmap(pfn, nr_pages, nid, altmap, pgmap); } static void depopulate_section_memmap(unsigned long pfn, unsigned long nr_pages, struct vmem_altmap *altmap) { unsigned long start = (unsigned long) pfn_to_page(pfn); unsigned long end = start + nr_pages * sizeof(struct page); vmemmap_free(start, end, altmap); } static void free_map_bootmem(struct page *memmap) { unsigned long start = (unsigned long)memmap; unsigned long end = (unsigned long)(memmap + PAGES_PER_SECTION); vmemmap_free(start, end, NULL); } static int clear_subsection_map(unsigned long pfn, unsigned long nr_pages) { DECLARE_BITMAP(map, SUBSECTIONS_PER_SECTION) = { 0 }; DECLARE_BITMAP(tmp, SUBSECTIONS_PER_SECTION) = { 0 }; struct mem_section *ms = __pfn_to_section(pfn); unsigned long *subsection_map = ms->usage ? &ms->usage->subsection_map[0] : NULL; subsection_mask_set(map, pfn, nr_pages); if (subsection_map) bitmap_and(tmp, map, subsection_map, SUBSECTIONS_PER_SECTION); if (WARN(!subsection_map || !bitmap_equal(tmp, map, SUBSECTIONS_PER_SECTION), "section already deactivated (%#lx + %ld)\n", pfn, nr_pages)) return -EINVAL; bitmap_xor(subsection_map, map, subsection_map, SUBSECTIONS_PER_SECTION); return 0; } static bool is_subsection_map_empty(struct mem_section *ms) { return bitmap_empty(&ms->usage->subsection_map[0], SUBSECTIONS_PER_SECTION); } static int fill_subsection_map(unsigned long pfn, unsigned long nr_pages) { struct mem_section *ms = __pfn_to_section(pfn); DECLARE_BITMAP(map, SUBSECTIONS_PER_SECTION) = { 0 }; unsigned long *subsection_map; int rc = 0; subsection_mask_set(map, pfn, nr_pages); subsection_map = &ms->usage->subsection_map[0]; if (bitmap_empty(map, SUBSECTIONS_PER_SECTION)) rc = -EINVAL; else if (bitmap_intersects(map, subsection_map, SUBSECTIONS_PER_SECTION)) rc = -EEXIST; else bitmap_or(subsection_map, map, subsection_map, SUBSECTIONS_PER_SECTION); return rc; } #else struct page * __meminit populate_section_memmap(unsigned long pfn, unsigned long nr_pages, int nid, struct vmem_altmap *altmap, struct dev_pagemap *pgmap) { return kvmalloc_node(array_size(sizeof(struct page), PAGES_PER_SECTION), GFP_KERNEL, nid); } static void depopulate_section_memmap(unsigned long pfn, unsigned long nr_pages, struct vmem_altmap *altmap) { kvfree(pfn_to_page(pfn)); } static void free_map_bootmem(struct page *memmap) { unsigned long maps_section_nr, removing_section_nr, i; unsigned long magic, nr_pages; struct page *page = virt_to_page(memmap); nr_pages = PAGE_ALIGN(PAGES_PER_SECTION * sizeof(struct page)) >> PAGE_SHIFT; for (i = 0; i < nr_pages; i++, page++) { magic = page->index; BUG_ON(magic == NODE_INFO); maps_section_nr = pfn_to_section_nr(page_to_pfn(page)); removing_section_nr = page_private(page); /* * When this function is called, the removing section is * logical offlined state. This means all pages are isolated * from page allocator. If removing section's memmap is placed * on the same section, it must not be freed. * If it is freed, page allocator may allocate it which will * be removed physically soon. */ if (maps_section_nr != removing_section_nr) put_page_bootmem(page); } } static int clear_subsection_map(unsigned long pfn, unsigned long nr_pages) { return 0; } static bool is_subsection_map_empty(struct mem_section *ms) { return true; } static int fill_subsection_map(unsigned long pfn, unsigned long nr_pages) { return 0; } #endif /* CONFIG_SPARSEMEM_VMEMMAP */ /* * To deactivate a memory region, there are 3 cases to handle across * two configurations (SPARSEMEM_VMEMMAP={y,n}): * * 1. deactivation of a partial hot-added section (only possible in * the SPARSEMEM_VMEMMAP=y case). * a) section was present at memory init. * b) section was hot-added post memory init. * 2. deactivation of a complete hot-added section. * 3. deactivation of a complete section from memory init. * * For 1, when subsection_map does not empty we will not be freeing the * usage map, but still need to free the vmemmap range. * * For 2 and 3, the SPARSEMEM_VMEMMAP={y,n} cases are unified */ static void section_deactivate(unsigned long pfn, unsigned long nr_pages, struct vmem_altmap *altmap) { struct mem_section *ms = __pfn_to_section(pfn); bool section_is_early = early_section(ms); struct page *memmap = NULL; bool empty; if (clear_subsection_map(pfn, nr_pages)) return; empty = is_subsection_map_empty(ms); if (empty) { unsigned long section_nr = pfn_to_section_nr(pfn); /* * When removing an early section, the usage map is kept (as the * usage maps of other sections fall into the same page). It * will be re-used when re-adding the section - which is then no * longer an early section. If the usage map is PageReserved, it * was allocated during boot. */ if (!PageReserved(virt_to_page(ms->usage))) { kfree(ms->usage); ms->usage = NULL; } memmap = sparse_decode_mem_map(ms->section_mem_map, section_nr); /* * Mark the section invalid so that valid_section() * return false. This prevents code from dereferencing * ms->usage array. */ ms->section_mem_map &= ~SECTION_HAS_MEM_MAP; } /* * The memmap of early sections is always fully populated. See * section_activate() and pfn_valid() . */ if (!section_is_early) depopulate_section_memmap(pfn, nr_pages, altmap); else if (memmap) free_map_bootmem(memmap); if (empty) ms->section_mem_map = (unsigned long)NULL; } static struct page * __meminit section_activate(int nid, unsigned long pfn, unsigned long nr_pages, struct vmem_altmap *altmap, struct dev_pagemap *pgmap) { struct mem_section *ms = __pfn_to_section(pfn); struct mem_section_usage *usage = NULL; struct page *memmap; int rc = 0; if (!ms->usage) { usage = kzalloc(mem_section_usage_size(), GFP_KERNEL); if (!usage) return ERR_PTR(-ENOMEM); ms->usage = usage; } rc = fill_subsection_map(pfn, nr_pages); if (rc) { if (usage) ms->usage = NULL; kfree(usage); return ERR_PTR(rc); } /* * The early init code does not consider partially populated * initial sections, it simply assumes that memory will never be * referenced. If we hot-add memory into such a section then we * do not need to populate the memmap and can simply reuse what * is already there. */ if (nr_pages < PAGES_PER_SECTION && early_section(ms)) return pfn_to_page(pfn); memmap = populate_section_memmap(pfn, nr_pages, nid, altmap, pgmap); if (!memmap) { section_deactivate(pfn, nr_pages, altmap); return ERR_PTR(-ENOMEM); } return memmap; } /** * sparse_add_section - add a memory section, or populate an existing one * @nid: The node to add section on * @start_pfn: start pfn of the memory range * @nr_pages: number of pfns to add in the section * @altmap: alternate pfns to allocate the memmap backing store * @pgmap: alternate compound page geometry for devmap mappings * * This is only intended for hotplug. * * Note that only VMEMMAP supports sub-section aligned hotplug, * the proper alignment and size are gated by check_pfn_span(). * * * Return: * * 0 - On success. * * -EEXIST - Section has been present. * * -ENOMEM - Out of memory. */ int __meminit sparse_add_section(int nid, unsigned long start_pfn, unsigned long nr_pages, struct vmem_altmap *altmap, struct dev_pagemap *pgmap) { unsigned long section_nr = pfn_to_section_nr(start_pfn); struct mem_section *ms; struct page *memmap; int ret; ret = sparse_index_init(section_nr, nid); if (ret < 0) return ret; memmap = section_activate(nid, start_pfn, nr_pages, altmap, pgmap); if (IS_ERR(memmap)) return PTR_ERR(memmap); /* * Poison uninitialized struct pages in order to catch invalid flags * combinations. */ page_init_poison(memmap, sizeof(struct page) * nr_pages); ms = __nr_to_section(section_nr); set_section_nid(section_nr, nid); __section_mark_present(ms, section_nr); /* Align memmap to section boundary in the subsection case */ if (section_nr_to_pfn(section_nr) != start_pfn) memmap = pfn_to_page(section_nr_to_pfn(section_nr)); sparse_init_one_section(ms, section_nr, memmap, ms->usage, 0); return 0; } void sparse_remove_section(struct mem_section *ms, unsigned long pfn, unsigned long nr_pages, unsigned long map_offset, struct vmem_altmap *altmap) { clear_hwpoisoned_pages(pfn_to_page(pfn) + map_offset, nr_pages - map_offset); section_deactivate(pfn, nr_pages, altmap); } #endif /* CONFIG_MEMORY_HOTPLUG */