diff options
Diffstat (limited to 'mm/sparse-vmemmap.c')
-rw-r--r-- | mm/sparse-vmemmap.c | 399 |
1 files changed, 0 insertions, 399 deletions
diff --git a/mm/sparse-vmemmap.c b/mm/sparse-vmemmap.c index 5f0ed4717ed0..46ae542118c0 100644 --- a/mm/sparse-vmemmap.c +++ b/mm/sparse-vmemmap.c @@ -27,408 +27,9 @@ #include <linux/spinlock.h> #include <linux/vmalloc.h> #include <linux/sched.h> -#include <linux/pgtable.h> -#include <linux/bootmem_info.h> #include <asm/dma.h> #include <asm/pgalloc.h> -#include <asm/tlbflush.h> - -#ifdef CONFIG_HUGETLB_PAGE_OPTIMIZE_VMEMMAP -/** - * struct vmemmap_remap_walk - walk vmemmap page table - * - * @remap_pte: called for each lowest-level entry (PTE). - * @nr_walked: the number of walked pte. - * @reuse_page: the page which is reused for the tail vmemmap pages. - * @reuse_addr: the virtual address of the @reuse_page page. - * @vmemmap_pages: the list head of the vmemmap pages that can be freed - * or is mapped from. - */ -struct vmemmap_remap_walk { - void (*remap_pte)(pte_t *pte, unsigned long addr, - struct vmemmap_remap_walk *walk); - unsigned long nr_walked; - struct page *reuse_page; - unsigned long reuse_addr; - struct list_head *vmemmap_pages; -}; - -static int __split_vmemmap_huge_pmd(pmd_t *pmd, unsigned long start) -{ - pmd_t __pmd; - int i; - unsigned long addr = start; - struct page *page = pmd_page(*pmd); - pte_t *pgtable = pte_alloc_one_kernel(&init_mm); - - if (!pgtable) - return -ENOMEM; - - pmd_populate_kernel(&init_mm, &__pmd, pgtable); - - for (i = 0; i < PMD_SIZE / PAGE_SIZE; i++, addr += PAGE_SIZE) { - pte_t entry, *pte; - pgprot_t pgprot = PAGE_KERNEL; - - entry = mk_pte(page + i, pgprot); - pte = pte_offset_kernel(&__pmd, addr); - set_pte_at(&init_mm, addr, pte, entry); - } - - spin_lock(&init_mm.page_table_lock); - if (likely(pmd_leaf(*pmd))) { - /* - * Higher order allocations from buddy allocator must be able to - * be treated as indepdenent small pages (as they can be freed - * individually). - */ - if (!PageReserved(page)) - split_page(page, get_order(PMD_SIZE)); - - /* Make pte visible before pmd. See comment in pmd_install(). */ - smp_wmb(); - pmd_populate_kernel(&init_mm, pmd, pgtable); - flush_tlb_kernel_range(start, start + PMD_SIZE); - } else { - pte_free_kernel(&init_mm, pgtable); - } - spin_unlock(&init_mm.page_table_lock); - - return 0; -} - -static int split_vmemmap_huge_pmd(pmd_t *pmd, unsigned long start) -{ - int leaf; - - spin_lock(&init_mm.page_table_lock); - leaf = pmd_leaf(*pmd); - spin_unlock(&init_mm.page_table_lock); - - if (!leaf) - return 0; - - return __split_vmemmap_huge_pmd(pmd, start); -} - -static void vmemmap_pte_range(pmd_t *pmd, unsigned long addr, - unsigned long end, - struct vmemmap_remap_walk *walk) -{ - pte_t *pte = pte_offset_kernel(pmd, addr); - - /* - * The reuse_page is found 'first' in table walk before we start - * remapping (which is calling @walk->remap_pte). - */ - if (!walk->reuse_page) { - walk->reuse_page = pte_page(*pte); - /* - * Because the reuse address is part of the range that we are - * walking, skip the reuse address range. - */ - addr += PAGE_SIZE; - pte++; - walk->nr_walked++; - } - - for (; addr != end; addr += PAGE_SIZE, pte++) { - walk->remap_pte(pte, addr, walk); - walk->nr_walked++; - } -} - -static int vmemmap_pmd_range(pud_t *pud, unsigned long addr, - unsigned long end, - struct vmemmap_remap_walk *walk) -{ - pmd_t *pmd; - unsigned long next; - - pmd = pmd_offset(pud, addr); - do { - int ret; - - ret = split_vmemmap_huge_pmd(pmd, addr & PMD_MASK); - if (ret) - return ret; - - next = pmd_addr_end(addr, end); - vmemmap_pte_range(pmd, addr, next, walk); - } while (pmd++, addr = next, addr != end); - - return 0; -} - -static int vmemmap_pud_range(p4d_t *p4d, unsigned long addr, - unsigned long end, - struct vmemmap_remap_walk *walk) -{ - pud_t *pud; - unsigned long next; - - pud = pud_offset(p4d, addr); - do { - int ret; - - next = pud_addr_end(addr, end); - ret = vmemmap_pmd_range(pud, addr, next, walk); - if (ret) - return ret; - } while (pud++, addr = next, addr != end); - - return 0; -} - -static int vmemmap_p4d_range(pgd_t *pgd, unsigned long addr, - unsigned long end, - struct vmemmap_remap_walk *walk) -{ - p4d_t *p4d; - unsigned long next; - - p4d = p4d_offset(pgd, addr); - do { - int ret; - - next = p4d_addr_end(addr, end); - ret = vmemmap_pud_range(p4d, addr, next, walk); - if (ret) - return ret; - } while (p4d++, addr = next, addr != end); - - return 0; -} - -static int vmemmap_remap_range(unsigned long start, unsigned long end, - struct vmemmap_remap_walk *walk) -{ - unsigned long addr = start; - unsigned long next; - pgd_t *pgd; - - VM_BUG_ON(!PAGE_ALIGNED(start)); - VM_BUG_ON(!PAGE_ALIGNED(end)); - - pgd = pgd_offset_k(addr); - do { - int ret; - - next = pgd_addr_end(addr, end); - ret = vmemmap_p4d_range(pgd, addr, next, walk); - if (ret) - return ret; - } while (pgd++, addr = next, addr != end); - - /* - * We only change the mapping of the vmemmap virtual address range - * [@start + PAGE_SIZE, end), so we only need to flush the TLB which - * belongs to the range. - */ - flush_tlb_kernel_range(start + PAGE_SIZE, end); - - return 0; -} - -/* - * Free a vmemmap page. A vmemmap page can be allocated from the memblock - * allocator or buddy allocator. If the PG_reserved flag is set, it means - * that it allocated from the memblock allocator, just free it via the - * free_bootmem_page(). Otherwise, use __free_page(). - */ -static inline void free_vmemmap_page(struct page *page) -{ - if (PageReserved(page)) - free_bootmem_page(page); - else - __free_page(page); -} - -/* Free a list of the vmemmap pages */ -static void free_vmemmap_page_list(struct list_head *list) -{ - struct page *page, *next; - - list_for_each_entry_safe(page, next, list, lru) { - list_del(&page->lru); - free_vmemmap_page(page); - } -} - -static void vmemmap_remap_pte(pte_t *pte, unsigned long addr, - struct vmemmap_remap_walk *walk) -{ - /* - * Remap the tail pages as read-only to catch illegal write operation - * to the tail pages. - */ - pgprot_t pgprot = PAGE_KERNEL_RO; - pte_t entry = mk_pte(walk->reuse_page, pgprot); - struct page *page = pte_page(*pte); - - list_add_tail(&page->lru, walk->vmemmap_pages); - set_pte_at(&init_mm, addr, pte, entry); -} - -/* - * How many struct page structs need to be reset. When we reuse the head - * struct page, the special metadata (e.g. page->flags or page->mapping) - * cannot copy to the tail struct page structs. The invalid value will be - * checked in the free_tail_pages_check(). In order to avoid the message - * of "corrupted mapping in tail page". We need to reset at least 3 (one - * head struct page struct and two tail struct page structs) struct page - * structs. - */ -#define NR_RESET_STRUCT_PAGE 3 - -static inline void reset_struct_pages(struct page *start) -{ - int i; - struct page *from = start + NR_RESET_STRUCT_PAGE; - - for (i = 0; i < NR_RESET_STRUCT_PAGE; i++) - memcpy(start + i, from, sizeof(*from)); -} - -static void vmemmap_restore_pte(pte_t *pte, unsigned long addr, - struct vmemmap_remap_walk *walk) -{ - pgprot_t pgprot = PAGE_KERNEL; - struct page *page; - void *to; - - BUG_ON(pte_page(*pte) != walk->reuse_page); - - page = list_first_entry(walk->vmemmap_pages, struct page, lru); - list_del(&page->lru); - to = page_to_virt(page); - copy_page(to, (void *)walk->reuse_addr); - reset_struct_pages(to); - - set_pte_at(&init_mm, addr, pte, mk_pte(page, pgprot)); -} - -/** - * vmemmap_remap_free - remap the vmemmap virtual address range [@start, @end) - * to the page which @reuse is mapped to, then free vmemmap - * which the range are mapped to. - * @start: start address of the vmemmap virtual address range that we want - * to remap. - * @end: end address of the vmemmap virtual address range that we want to - * remap. - * @reuse: reuse address. - * - * Return: %0 on success, negative error code otherwise. - */ -int vmemmap_remap_free(unsigned long start, unsigned long end, - unsigned long reuse) -{ - int ret; - LIST_HEAD(vmemmap_pages); - struct vmemmap_remap_walk walk = { - .remap_pte = vmemmap_remap_pte, - .reuse_addr = reuse, - .vmemmap_pages = &vmemmap_pages, - }; - - /* - * In order to make remapping routine most efficient for the huge pages, - * the routine of vmemmap page table walking has the following rules - * (see more details from the vmemmap_pte_range()): - * - * - The range [@start, @end) and the range [@reuse, @reuse + PAGE_SIZE) - * should be continuous. - * - The @reuse address is part of the range [@reuse, @end) that we are - * walking which is passed to vmemmap_remap_range(). - * - The @reuse address is the first in the complete range. - * - * So we need to make sure that @start and @reuse meet the above rules. - */ - BUG_ON(start - reuse != PAGE_SIZE); - - mmap_read_lock(&init_mm); - ret = vmemmap_remap_range(reuse, end, &walk); - if (ret && walk.nr_walked) { - end = reuse + walk.nr_walked * PAGE_SIZE; - /* - * vmemmap_pages contains pages from the previous - * vmemmap_remap_range call which failed. These - * are pages which were removed from the vmemmap. - * They will be restored in the following call. - */ - walk = (struct vmemmap_remap_walk) { - .remap_pte = vmemmap_restore_pte, - .reuse_addr = reuse, - .vmemmap_pages = &vmemmap_pages, - }; - - vmemmap_remap_range(reuse, end, &walk); - } - mmap_read_unlock(&init_mm); - - free_vmemmap_page_list(&vmemmap_pages); - - return ret; -} - -static int alloc_vmemmap_page_list(unsigned long start, unsigned long end, - gfp_t gfp_mask, struct list_head *list) -{ - unsigned long nr_pages = (end - start) >> PAGE_SHIFT; - int nid = page_to_nid((struct page *)start); - struct page *page, *next; - - while (nr_pages--) { - page = alloc_pages_node(nid, gfp_mask, 0); - if (!page) - goto out; - list_add_tail(&page->lru, list); - } - - return 0; -out: - list_for_each_entry_safe(page, next, list, lru) - __free_pages(page, 0); - return -ENOMEM; -} - -/** - * vmemmap_remap_alloc - remap the vmemmap virtual address range [@start, end) - * to the page which is from the @vmemmap_pages - * respectively. - * @start: start address of the vmemmap virtual address range that we want - * to remap. - * @end: end address of the vmemmap virtual address range that we want to - * remap. - * @reuse: reuse address. - * @gfp_mask: GFP flag for allocating vmemmap pages. - * - * Return: %0 on success, negative error code otherwise. - */ -int vmemmap_remap_alloc(unsigned long start, unsigned long end, - unsigned long reuse, gfp_t gfp_mask) -{ - LIST_HEAD(vmemmap_pages); - struct vmemmap_remap_walk walk = { - .remap_pte = vmemmap_restore_pte, - .reuse_addr = reuse, - .vmemmap_pages = &vmemmap_pages, - }; - - /* See the comment in the vmemmap_remap_free(). */ - BUG_ON(start - reuse != PAGE_SIZE); - - if (alloc_vmemmap_page_list(start, end, gfp_mask, &vmemmap_pages)) - return -ENOMEM; - - mmap_read_lock(&init_mm); - vmemmap_remap_range(reuse, end, &walk); - mmap_read_unlock(&init_mm); - - return 0; -} -#endif /* CONFIG_HUGETLB_PAGE_OPTIMIZE_VMEMMAP */ /* * Allocate a block of memory to be used to back the virtual memory map |