diff options
Diffstat (limited to 'mm/sparse-vmemmap.c')
| -rw-r--r-- | mm/sparse-vmemmap.c | 227 |
1 files changed, 227 insertions, 0 deletions
diff --git a/mm/sparse-vmemmap.c b/mm/sparse-vmemmap.c new file mode 100644 index 00000000..64b98409 --- /dev/null +++ b/mm/sparse-vmemmap.c @@ -0,0 +1,227 @@ +/* + * Virtual Memory Map support + * + * (C) 2007 sgi. Christoph Lameter. + * + * Virtual memory maps allow VM primitives pfn_to_page, page_to_pfn, + * virt_to_page, page_address() to be implemented as a base offset + * calculation without memory access. + * + * However, virtual mappings need a page table and TLBs. Many Linux + * architectures already map their physical space using 1-1 mappings + * via TLBs. For those arches the virtual memory map is essentially + * for free if we use the same page size as the 1-1 mappings. In that + * case the overhead consists of a few additional pages that are + * allocated to create a view of memory for vmemmap. + * + * The architecture is expected to provide a vmemmap_populate() function + * to instantiate the mapping. + */ +#include <linux/mm.h> +#include <linux/mmzone.h> +#include <linux/bootmem.h> +#include <linux/highmem.h> +#include <linux/module.h> +#include <linux/slab.h> +#include <linux/spinlock.h> +#include <linux/vmalloc.h> +#include <linux/sched.h> +#include <asm/dma.h> +#include <asm/pgalloc.h> +#include <asm/pgtable.h> + +/* + * Allocate a block of memory to be used to back the virtual memory map + * or to back the page tables that are used to create the mapping. + * Uses the main allocators if they are available, else bootmem. + */ + +static void * __init_refok __earlyonly_bootmem_alloc(int node, + unsigned long size, + unsigned long align, + unsigned long goal) +{ + return __alloc_bootmem_node_high(NODE_DATA(node), size, align, goal); +} + +static void *vmemmap_buf; +static void *vmemmap_buf_end; + +void * __meminit vmemmap_alloc_block(unsigned long size, int node) +{ + /* If the main allocator is up use that, fallback to bootmem. */ + if (slab_is_available()) { + struct page *page; + + if (node_state(node, N_HIGH_MEMORY)) + page = alloc_pages_node(node, + GFP_KERNEL | __GFP_ZERO, get_order(size)); + else + page = alloc_pages(GFP_KERNEL | __GFP_ZERO, + get_order(size)); + if (page) + return page_address(page); + return NULL; + } else + return __earlyonly_bootmem_alloc(node, size, size, + __pa(MAX_DMA_ADDRESS)); +} + +/* need to make sure size is all the same during early stage */ +void * __meminit vmemmap_alloc_block_buf(unsigned long size, int node) +{ + void *ptr; + + if (!vmemmap_buf) + return vmemmap_alloc_block(size, node); + + /* take the from buf */ + ptr = (void *)ALIGN((unsigned long)vmemmap_buf, size); + if (ptr + size > vmemmap_buf_end) + return vmemmap_alloc_block(size, node); + + vmemmap_buf = ptr + size; + + return ptr; +} + +void __meminit vmemmap_verify(pte_t *pte, int node, + unsigned long start, unsigned long end) +{ + unsigned long pfn = pte_pfn(*pte); + int actual_node = early_pfn_to_nid(pfn); + + if (node_distance(actual_node, node) > LOCAL_DISTANCE) + printk(KERN_WARNING "[%lx-%lx] potential offnode " + "page_structs\n", start, end - 1); +} + +pte_t * __meminit vmemmap_pte_populate(pmd_t *pmd, unsigned long addr, int node) +{ + pte_t *pte = pte_offset_kernel(pmd, addr); + if (pte_none(*pte)) { + pte_t entry; + void *p = vmemmap_alloc_block_buf(PAGE_SIZE, node); + if (!p) + return NULL; + entry = pfn_pte(__pa(p) >> PAGE_SHIFT, PAGE_KERNEL); + set_pte_at(&init_mm, addr, pte, entry); + } + return pte; +} + +pmd_t * __meminit vmemmap_pmd_populate(pud_t *pud, unsigned long addr, int node) +{ + pmd_t *pmd = pmd_offset(pud, addr); + if (pmd_none(*pmd)) { + void *p = vmemmap_alloc_block(PAGE_SIZE, node); + if (!p) + return NULL; + pmd_populate_kernel(&init_mm, pmd, p); + } + return pmd; +} + +pud_t * __meminit vmemmap_pud_populate(pgd_t *pgd, unsigned long addr, int node) +{ + pud_t *pud = pud_offset(pgd, addr); + if (pud_none(*pud)) { + void *p = vmemmap_alloc_block(PAGE_SIZE, node); + if (!p) + return NULL; + pud_populate(&init_mm, pud, p); + } + return pud; +} + +pgd_t * __meminit vmemmap_pgd_populate(unsigned long addr, int node) +{ + pgd_t *pgd = pgd_offset_k(addr); + if (pgd_none(*pgd)) { + void *p = vmemmap_alloc_block(PAGE_SIZE, node); + if (!p) + return NULL; + pgd_populate(&init_mm, pgd, p); + } + return pgd; +} + +int __meminit vmemmap_populate_basepages(struct page *start_page, + unsigned long size, int node) +{ + unsigned long addr = (unsigned long)start_page; + unsigned long end = (unsigned long)(start_page + size); + pgd_t *pgd; + pud_t *pud; + pmd_t *pmd; + pte_t *pte; + + for (; addr < end; addr += PAGE_SIZE) { + pgd = vmemmap_pgd_populate(addr, node); + if (!pgd) + return -ENOMEM; + pud = vmemmap_pud_populate(pgd, addr, node); + if (!pud) + return -ENOMEM; + pmd = vmemmap_pmd_populate(pud, addr, node); + if (!pmd) + return -ENOMEM; + pte = vmemmap_pte_populate(pmd, addr, node); + if (!pte) + return -ENOMEM; + vmemmap_verify(pte, node, addr, addr + PAGE_SIZE); + } + + return 0; +} + +struct page * __meminit sparse_mem_map_populate(unsigned long pnum, int nid) +{ + struct page *map = pfn_to_page(pnum * PAGES_PER_SECTION); + int error = vmemmap_populate(map, PAGES_PER_SECTION, nid); + if (error) + return NULL; + + return map; +} + +void __init sparse_mem_maps_populate_node(struct page **map_map, + unsigned long pnum_begin, + unsigned long pnum_end, + unsigned long map_count, int nodeid) +{ + unsigned long pnum; + unsigned long size = sizeof(struct page) * PAGES_PER_SECTION; + void *vmemmap_buf_start; + + size = ALIGN(size, PMD_SIZE); + vmemmap_buf_start = __earlyonly_bootmem_alloc(nodeid, size * map_count, + PMD_SIZE, __pa(MAX_DMA_ADDRESS)); + + if (vmemmap_buf_start) { + vmemmap_buf = vmemmap_buf_start; + vmemmap_buf_end = vmemmap_buf_start + size * map_count; + } + + for (pnum = pnum_begin; pnum < pnum_end; pnum++) { + struct mem_section *ms; + + if (!present_section_nr(pnum)) + continue; + + map_map[pnum] = sparse_mem_map_populate(pnum, nodeid); + if (map_map[pnum]) + continue; + ms = __nr_to_section(pnum); + printk(KERN_ERR "%s: sparsemem memory map backing failed " + "some memory will not be available.\n", __func__); + ms->section_mem_map = 0; + } + + if (vmemmap_buf_start) { + /* need to free left buf */ + free_bootmem(__pa(vmemmap_buf), vmemmap_buf_end - vmemmap_buf); + vmemmap_buf = NULL; + vmemmap_buf_end = NULL; + } +} |