![Yasunori Goto](/assets/img/avatar_default.png)
This patch set is to free pages which is allocated by bootmem for memory-hotremove. Some structures of memory management are allocated by bootmem. ex) memmap, etc. To remove memory physically, some of them must be freed according to circumstance. This patch set makes basis to free those pages, and free memmaps. Basic my idea is using remain members of struct page to remember information of users of bootmem (section number or node id). When the section is removing, kernel can confirm it. By this information, some issues can be solved. 1) When the memmap of removing section is allocated on other section by bootmem, it should/can be free. 2) When the memmap of removing section is allocated on the same section, it shouldn't be freed. Because the section has to be logical memory offlined already and all pages must be isolated against page allocater. If it is freed, page allocator may use it which will be removed physically soon. 3) When removing section has other section's memmap, kernel will be able to show easily which section should be removed before it for user. (Not implemented yet) 4) When the above case 2), the page isolation will be able to check and skip memmap's page when logical memory offline (offline_pages()). Current page isolation code fails in this case because this page is just reserved page and it can't distinguish this pages can be removed or not. But, it will be able to do by this patch. (Not implemented yet.) 5) The node information like pgdat has similar issues. But, this will be able to be solved too by this. (Not implemented yet, but, remembering node id in the pages.) Fortunately, current bootmem allocator just keeps PageReserved flags, and doesn't use any other members of page struct. The users of bootmem doesn't use them too. This patch: This is to register information which is node or section's id. Kernel can distinguish which node/section uses the pages allcated by bootmem. This is basis for hot-remove sections or nodes. Signed-off-by: Yasunori Goto <y-goto@jp.fujitsu.com> Cc: Badari Pulavarty <pbadari@us.ibm.com> Cc: Yinghai Lu <yhlu.kernel@gmail.com> Cc: Yasunori Goto <y-goto@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
498 lines
12 KiB
C
498 lines
12 KiB
C
/*
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* sparse memory mappings.
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*/
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#include <linux/mm.h>
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#include <linux/mmzone.h>
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#include <linux/bootmem.h>
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#include <linux/highmem.h>
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#include <linux/module.h>
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#include <linux/spinlock.h>
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#include <linux/vmalloc.h>
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#include <asm/dma.h>
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#include <asm/pgalloc.h>
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#include <asm/pgtable.h>
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/*
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* Permanent SPARSEMEM data:
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*
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* 1) mem_section - memory sections, mem_map's for valid memory
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*/
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#ifdef CONFIG_SPARSEMEM_EXTREME
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struct mem_section *mem_section[NR_SECTION_ROOTS]
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____cacheline_internodealigned_in_smp;
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#else
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struct mem_section mem_section[NR_SECTION_ROOTS][SECTIONS_PER_ROOT]
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____cacheline_internodealigned_in_smp;
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#endif
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EXPORT_SYMBOL(mem_section);
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#ifdef NODE_NOT_IN_PAGE_FLAGS
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/*
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* If we did not store the node number in the page then we have to
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* do a lookup in the section_to_node_table in order to find which
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* node the page belongs to.
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*/
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#if MAX_NUMNODES <= 256
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static u8 section_to_node_table[NR_MEM_SECTIONS] __cacheline_aligned;
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#else
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static u16 section_to_node_table[NR_MEM_SECTIONS] __cacheline_aligned;
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#endif
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int page_to_nid(struct page *page)
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{
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return section_to_node_table[page_to_section(page)];
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}
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EXPORT_SYMBOL(page_to_nid);
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static void set_section_nid(unsigned long section_nr, int nid)
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{
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section_to_node_table[section_nr] = nid;
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}
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#else /* !NODE_NOT_IN_PAGE_FLAGS */
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static inline void set_section_nid(unsigned long section_nr, int nid)
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{
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}
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#endif
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#ifdef CONFIG_SPARSEMEM_EXTREME
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static struct mem_section noinline __init_refok *sparse_index_alloc(int nid)
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{
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struct mem_section *section = NULL;
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unsigned long array_size = SECTIONS_PER_ROOT *
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sizeof(struct mem_section);
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if (slab_is_available())
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section = kmalloc_node(array_size, GFP_KERNEL, nid);
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else
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section = alloc_bootmem_node(NODE_DATA(nid), array_size);
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if (section)
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memset(section, 0, array_size);
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return section;
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}
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static int __meminit sparse_index_init(unsigned long section_nr, int nid)
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{
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static DEFINE_SPINLOCK(index_init_lock);
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unsigned long root = SECTION_NR_TO_ROOT(section_nr);
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struct mem_section *section;
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int ret = 0;
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if (mem_section[root])
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return -EEXIST;
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section = sparse_index_alloc(nid);
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if (!section)
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return -ENOMEM;
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/*
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* This lock keeps two different sections from
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* reallocating for the same index
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*/
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spin_lock(&index_init_lock);
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if (mem_section[root]) {
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ret = -EEXIST;
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goto out;
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}
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mem_section[root] = section;
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out:
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spin_unlock(&index_init_lock);
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return ret;
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}
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#else /* !SPARSEMEM_EXTREME */
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static inline int sparse_index_init(unsigned long section_nr, int nid)
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{
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return 0;
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}
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#endif
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/*
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* Although written for the SPARSEMEM_EXTREME case, this happens
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* to also work for the flat array case because
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* NR_SECTION_ROOTS==NR_MEM_SECTIONS.
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*/
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int __section_nr(struct mem_section* ms)
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{
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unsigned long root_nr;
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struct mem_section* root;
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for (root_nr = 0; root_nr < NR_SECTION_ROOTS; root_nr++) {
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root = __nr_to_section(root_nr * SECTIONS_PER_ROOT);
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if (!root)
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continue;
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if ((ms >= root) && (ms < (root + SECTIONS_PER_ROOT)))
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break;
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}
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return (root_nr * SECTIONS_PER_ROOT) + (ms - root);
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}
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/*
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* During early boot, before section_mem_map is used for an actual
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* mem_map, we use section_mem_map to store the section's NUMA
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* node. This keeps us from having to use another data structure. The
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* node information is cleared just before we store the real mem_map.
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*/
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static inline unsigned long sparse_encode_early_nid(int nid)
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{
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return (nid << SECTION_NID_SHIFT);
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}
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static inline int sparse_early_nid(struct mem_section *section)
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{
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return (section->section_mem_map >> SECTION_NID_SHIFT);
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}
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/* Record a memory area against a node. */
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void __init memory_present(int nid, unsigned long start, unsigned long end)
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{
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unsigned long max_arch_pfn = 1UL << (MAX_PHYSMEM_BITS-PAGE_SHIFT);
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unsigned long pfn;
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/*
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* Sanity checks - do not allow an architecture to pass
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* in larger pfns than the maximum scope of sparsemem:
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*/
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if (start >= max_arch_pfn)
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return;
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if (end >= max_arch_pfn)
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end = max_arch_pfn;
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start &= PAGE_SECTION_MASK;
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for (pfn = start; pfn < end; pfn += PAGES_PER_SECTION) {
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unsigned long section = pfn_to_section_nr(pfn);
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struct mem_section *ms;
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sparse_index_init(section, nid);
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set_section_nid(section, nid);
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ms = __nr_to_section(section);
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if (!ms->section_mem_map)
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ms->section_mem_map = sparse_encode_early_nid(nid) |
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SECTION_MARKED_PRESENT;
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}
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}
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/*
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* Only used by the i386 NUMA architecures, but relatively
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* generic code.
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*/
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unsigned long __init node_memmap_size_bytes(int nid, unsigned long start_pfn,
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unsigned long end_pfn)
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{
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unsigned long pfn;
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unsigned long nr_pages = 0;
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for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
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if (nid != early_pfn_to_nid(pfn))
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continue;
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if (pfn_present(pfn))
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nr_pages += PAGES_PER_SECTION;
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}
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return nr_pages * sizeof(struct page);
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}
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/*
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* Subtle, we encode the real pfn into the mem_map such that
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* the identity pfn - section_mem_map will return the actual
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* physical page frame number.
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*/
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static unsigned long sparse_encode_mem_map(struct page *mem_map, unsigned long pnum)
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{
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return (unsigned long)(mem_map - (section_nr_to_pfn(pnum)));
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}
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/*
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* Decode mem_map from the coded memmap
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*/
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struct page *sparse_decode_mem_map(unsigned long coded_mem_map, unsigned long pnum)
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{
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/* mask off the extra low bits of information */
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coded_mem_map &= SECTION_MAP_MASK;
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return ((struct page *)coded_mem_map) + section_nr_to_pfn(pnum);
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}
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static int __meminit sparse_init_one_section(struct mem_section *ms,
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unsigned long pnum, struct page *mem_map,
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unsigned long *pageblock_bitmap)
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{
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if (!present_section(ms))
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return -EINVAL;
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ms->section_mem_map &= ~SECTION_MAP_MASK;
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ms->section_mem_map |= sparse_encode_mem_map(mem_map, pnum) |
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SECTION_HAS_MEM_MAP;
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ms->pageblock_flags = pageblock_bitmap;
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return 1;
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}
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unsigned long usemap_size(void)
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{
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unsigned long size_bytes;
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size_bytes = roundup(SECTION_BLOCKFLAGS_BITS, 8) / 8;
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size_bytes = roundup(size_bytes, sizeof(unsigned long));
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return size_bytes;
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}
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#ifdef CONFIG_MEMORY_HOTPLUG
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static unsigned long *__kmalloc_section_usemap(void)
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{
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return kmalloc(usemap_size(), GFP_KERNEL);
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}
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#endif /* CONFIG_MEMORY_HOTPLUG */
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static unsigned long *__init sparse_early_usemap_alloc(unsigned long pnum)
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{
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unsigned long *usemap;
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struct mem_section *ms = __nr_to_section(pnum);
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int nid = sparse_early_nid(ms);
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usemap = alloc_bootmem_node(NODE_DATA(nid), usemap_size());
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if (usemap)
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return usemap;
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/* Stupid: suppress gcc warning for SPARSEMEM && !NUMA */
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nid = 0;
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printk(KERN_WARNING "%s: allocation failed\n", __FUNCTION__);
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return NULL;
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}
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#ifndef CONFIG_SPARSEMEM_VMEMMAP
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struct page __init *sparse_mem_map_populate(unsigned long pnum, int nid)
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{
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struct page *map;
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map = alloc_remap(nid, sizeof(struct page) * PAGES_PER_SECTION);
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if (map)
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return map;
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map = alloc_bootmem_node(NODE_DATA(nid),
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sizeof(struct page) * PAGES_PER_SECTION);
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return map;
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}
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#endif /* !CONFIG_SPARSEMEM_VMEMMAP */
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struct page __init *sparse_early_mem_map_alloc(unsigned long pnum)
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{
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struct page *map;
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struct mem_section *ms = __nr_to_section(pnum);
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int nid = sparse_early_nid(ms);
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map = sparse_mem_map_populate(pnum, nid);
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if (map)
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return map;
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printk(KERN_ERR "%s: sparsemem memory map backing failed "
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"some memory will not be available.\n", __FUNCTION__);
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ms->section_mem_map = 0;
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return NULL;
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}
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void __attribute__((weak)) __meminit vmemmap_populate_print_last(void)
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{
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}
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/*
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* Allocate the accumulated non-linear sections, allocate a mem_map
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* for each and record the physical to section mapping.
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*/
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void __init sparse_init(void)
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{
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unsigned long pnum;
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struct page *map;
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unsigned long *usemap;
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unsigned long **usemap_map;
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int size;
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/*
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* map is using big page (aka 2M in x86 64 bit)
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* usemap is less one page (aka 24 bytes)
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* so alloc 2M (with 2M align) and 24 bytes in turn will
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* make next 2M slip to one more 2M later.
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* then in big system, the memory will have a lot of holes...
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* here try to allocate 2M pages continously.
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*
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* powerpc need to call sparse_init_one_section right after each
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* sparse_early_mem_map_alloc, so allocate usemap_map at first.
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*/
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size = sizeof(unsigned long *) * NR_MEM_SECTIONS;
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usemap_map = alloc_bootmem(size);
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if (!usemap_map)
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panic("can not allocate usemap_map\n");
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for (pnum = 0; pnum < NR_MEM_SECTIONS; pnum++) {
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if (!present_section_nr(pnum))
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continue;
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usemap_map[pnum] = sparse_early_usemap_alloc(pnum);
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}
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for (pnum = 0; pnum < NR_MEM_SECTIONS; pnum++) {
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if (!present_section_nr(pnum))
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continue;
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usemap = usemap_map[pnum];
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if (!usemap)
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continue;
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map = sparse_early_mem_map_alloc(pnum);
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if (!map)
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continue;
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sparse_init_one_section(__nr_to_section(pnum), pnum, map,
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usemap);
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}
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vmemmap_populate_print_last();
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free_bootmem(__pa(usemap_map), size);
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}
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#ifdef CONFIG_MEMORY_HOTPLUG
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#ifdef CONFIG_SPARSEMEM_VMEMMAP
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static inline struct page *kmalloc_section_memmap(unsigned long pnum, int nid,
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unsigned long nr_pages)
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{
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/* This will make the necessary allocations eventually. */
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return sparse_mem_map_populate(pnum, nid);
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}
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static void __kfree_section_memmap(struct page *memmap, unsigned long nr_pages)
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{
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return; /* XXX: Not implemented yet */
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}
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#else
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static struct page *__kmalloc_section_memmap(unsigned long nr_pages)
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{
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struct page *page, *ret;
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unsigned long memmap_size = sizeof(struct page) * nr_pages;
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page = alloc_pages(GFP_KERNEL|__GFP_NOWARN, get_order(memmap_size));
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if (page)
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goto got_map_page;
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ret = vmalloc(memmap_size);
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if (ret)
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goto got_map_ptr;
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return NULL;
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got_map_page:
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ret = (struct page *)pfn_to_kaddr(page_to_pfn(page));
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got_map_ptr:
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memset(ret, 0, memmap_size);
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return ret;
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}
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static inline struct page *kmalloc_section_memmap(unsigned long pnum, int nid,
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unsigned long nr_pages)
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{
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return __kmalloc_section_memmap(nr_pages);
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}
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static void __kfree_section_memmap(struct page *memmap, unsigned long nr_pages)
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{
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if (is_vmalloc_addr(memmap))
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vfree(memmap);
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else
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free_pages((unsigned long)memmap,
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get_order(sizeof(struct page) * nr_pages));
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}
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#endif /* CONFIG_SPARSEMEM_VMEMMAP */
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static void free_section_usemap(struct page *memmap, unsigned long *usemap)
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{
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if (!usemap)
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return;
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/*
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* Check to see if allocation came from hot-plug-add
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*/
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if (PageSlab(virt_to_page(usemap))) {
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kfree(usemap);
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if (memmap)
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__kfree_section_memmap(memmap, PAGES_PER_SECTION);
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return;
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}
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/*
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* TODO: Allocations came from bootmem - how do I free up ?
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*/
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printk(KERN_WARNING "Not freeing up allocations from bootmem "
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"- leaking memory\n");
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}
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/*
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* returns the number of sections whose mem_maps were properly
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* set. If this is <=0, then that means that the passed-in
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* map was not consumed and must be freed.
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*/
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int sparse_add_one_section(struct zone *zone, unsigned long start_pfn,
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int nr_pages)
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{
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unsigned long section_nr = pfn_to_section_nr(start_pfn);
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struct pglist_data *pgdat = zone->zone_pgdat;
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struct mem_section *ms;
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struct page *memmap;
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unsigned long *usemap;
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unsigned long flags;
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int ret;
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/*
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* no locking for this, because it does its own
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* plus, it does a kmalloc
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*/
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ret = sparse_index_init(section_nr, pgdat->node_id);
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if (ret < 0 && ret != -EEXIST)
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return ret;
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memmap = kmalloc_section_memmap(section_nr, pgdat->node_id, nr_pages);
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if (!memmap)
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return -ENOMEM;
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usemap = __kmalloc_section_usemap();
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if (!usemap) {
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__kfree_section_memmap(memmap, nr_pages);
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return -ENOMEM;
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}
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pgdat_resize_lock(pgdat, &flags);
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ms = __pfn_to_section(start_pfn);
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if (ms->section_mem_map & SECTION_MARKED_PRESENT) {
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ret = -EEXIST;
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goto out;
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}
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ms->section_mem_map |= SECTION_MARKED_PRESENT;
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ret = sparse_init_one_section(ms, section_nr, memmap, usemap);
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out:
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pgdat_resize_unlock(pgdat, &flags);
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if (ret <= 0) {
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kfree(usemap);
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__kfree_section_memmap(memmap, nr_pages);
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}
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return ret;
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}
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void sparse_remove_one_section(struct zone *zone, struct mem_section *ms)
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{
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struct page *memmap = NULL;
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unsigned long *usemap = NULL;
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if (ms->section_mem_map) {
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usemap = ms->pageblock_flags;
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memmap = sparse_decode_mem_map(ms->section_mem_map,
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__section_nr(ms));
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ms->section_mem_map = 0;
|
|
ms->pageblock_flags = NULL;
|
|
}
|
|
|
|
free_section_usemap(memmap, usemap);
|
|
}
|
|
#endif
|