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author | Thomas Gleixner <tglx@linutronix.de> | 2007-10-11 11:16:47 +0200 |
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committer | Thomas Gleixner <tglx@linutronix.de> | 2007-10-11 11:16:47 +0200 |
commit | ad757b6aa5801b81dec609d87753604a06313c53 (patch) | |
tree | 7bb40460e1729ad370b5ae75e65f9e6a0e824328 /arch/x86/mm/hugetlbpage.c | |
parent | i386: move boot (diff) | |
download | linux-ad757b6aa5801b81dec609d87753604a06313c53.tar.xz linux-ad757b6aa5801b81dec609d87753604a06313c53.zip |
i386: move mm
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/x86/mm/hugetlbpage.c')
-rw-r--r-- | arch/x86/mm/hugetlbpage.c | 391 |
1 files changed, 391 insertions, 0 deletions
diff --git a/arch/x86/mm/hugetlbpage.c b/arch/x86/mm/hugetlbpage.c new file mode 100644 index 000000000000..6c06d9c0488e --- /dev/null +++ b/arch/x86/mm/hugetlbpage.c @@ -0,0 +1,391 @@ +/* + * IA-32 Huge TLB Page Support for Kernel. + * + * Copyright (C) 2002, Rohit Seth <rohit.seth@intel.com> + */ + +#include <linux/init.h> +#include <linux/fs.h> +#include <linux/mm.h> +#include <linux/hugetlb.h> +#include <linux/pagemap.h> +#include <linux/slab.h> +#include <linux/err.h> +#include <linux/sysctl.h> +#include <asm/mman.h> +#include <asm/tlb.h> +#include <asm/tlbflush.h> + +static unsigned long page_table_shareable(struct vm_area_struct *svma, + struct vm_area_struct *vma, + unsigned long addr, pgoff_t idx) +{ + unsigned long saddr = ((idx - svma->vm_pgoff) << PAGE_SHIFT) + + svma->vm_start; + unsigned long sbase = saddr & PUD_MASK; + unsigned long s_end = sbase + PUD_SIZE; + + /* + * match the virtual addresses, permission and the alignment of the + * page table page. + */ + if (pmd_index(addr) != pmd_index(saddr) || + vma->vm_flags != svma->vm_flags || + sbase < svma->vm_start || svma->vm_end < s_end) + return 0; + + return saddr; +} + +static int vma_shareable(struct vm_area_struct *vma, unsigned long addr) +{ + unsigned long base = addr & PUD_MASK; + unsigned long end = base + PUD_SIZE; + + /* + * check on proper vm_flags and page table alignment + */ + if (vma->vm_flags & VM_MAYSHARE && + vma->vm_start <= base && end <= vma->vm_end) + return 1; + return 0; +} + +/* + * search for a shareable pmd page for hugetlb. + */ +static void huge_pmd_share(struct mm_struct *mm, unsigned long addr, pud_t *pud) +{ + struct vm_area_struct *vma = find_vma(mm, addr); + struct address_space *mapping = vma->vm_file->f_mapping; + pgoff_t idx = ((addr - vma->vm_start) >> PAGE_SHIFT) + + vma->vm_pgoff; + struct prio_tree_iter iter; + struct vm_area_struct *svma; + unsigned long saddr; + pte_t *spte = NULL; + + if (!vma_shareable(vma, addr)) + return; + + spin_lock(&mapping->i_mmap_lock); + vma_prio_tree_foreach(svma, &iter, &mapping->i_mmap, idx, idx) { + if (svma == vma) + continue; + + saddr = page_table_shareable(svma, vma, addr, idx); + if (saddr) { + spte = huge_pte_offset(svma->vm_mm, saddr); + if (spte) { + get_page(virt_to_page(spte)); + break; + } + } + } + + if (!spte) + goto out; + + spin_lock(&mm->page_table_lock); + if (pud_none(*pud)) + pud_populate(mm, pud, (unsigned long) spte & PAGE_MASK); + else + put_page(virt_to_page(spte)); + spin_unlock(&mm->page_table_lock); +out: + spin_unlock(&mapping->i_mmap_lock); +} + +/* + * unmap huge page backed by shared pte. + * + * Hugetlb pte page is ref counted at the time of mapping. If pte is shared + * indicated by page_count > 1, unmap is achieved by clearing pud and + * decrementing the ref count. If count == 1, the pte page is not shared. + * + * called with vma->vm_mm->page_table_lock held. + * + * returns: 1 successfully unmapped a shared pte page + * 0 the underlying pte page is not shared, or it is the last user + */ +int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep) +{ + pgd_t *pgd = pgd_offset(mm, *addr); + pud_t *pud = pud_offset(pgd, *addr); + + BUG_ON(page_count(virt_to_page(ptep)) == 0); + if (page_count(virt_to_page(ptep)) == 1) + return 0; + + pud_clear(pud); + put_page(virt_to_page(ptep)); + *addr = ALIGN(*addr, HPAGE_SIZE * PTRS_PER_PTE) - HPAGE_SIZE; + return 1; +} + +pte_t *huge_pte_alloc(struct mm_struct *mm, unsigned long addr) +{ + pgd_t *pgd; + pud_t *pud; + pte_t *pte = NULL; + + pgd = pgd_offset(mm, addr); + pud = pud_alloc(mm, pgd, addr); + if (pud) { + if (pud_none(*pud)) + huge_pmd_share(mm, addr, pud); + pte = (pte_t *) pmd_alloc(mm, pud, addr); + } + BUG_ON(pte && !pte_none(*pte) && !pte_huge(*pte)); + + return pte; +} + +pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr) +{ + pgd_t *pgd; + pud_t *pud; + pmd_t *pmd = NULL; + + pgd = pgd_offset(mm, addr); + if (pgd_present(*pgd)) { + pud = pud_offset(pgd, addr); + if (pud_present(*pud)) + pmd = pmd_offset(pud, addr); + } + return (pte_t *) pmd; +} + +#if 0 /* This is just for testing */ +struct page * +follow_huge_addr(struct mm_struct *mm, unsigned long address, int write) +{ + unsigned long start = address; + int length = 1; + int nr; + struct page *page; + struct vm_area_struct *vma; + + vma = find_vma(mm, addr); + if (!vma || !is_vm_hugetlb_page(vma)) + return ERR_PTR(-EINVAL); + + pte = huge_pte_offset(mm, address); + + /* hugetlb should be locked, and hence, prefaulted */ + WARN_ON(!pte || pte_none(*pte)); + + page = &pte_page(*pte)[vpfn % (HPAGE_SIZE/PAGE_SIZE)]; + + WARN_ON(!PageCompound(page)); + + return page; +} + +int pmd_huge(pmd_t pmd) +{ + return 0; +} + +struct page * +follow_huge_pmd(struct mm_struct *mm, unsigned long address, + pmd_t *pmd, int write) +{ + return NULL; +} + +#else + +struct page * +follow_huge_addr(struct mm_struct *mm, unsigned long address, int write) +{ + return ERR_PTR(-EINVAL); +} + +int pmd_huge(pmd_t pmd) +{ + return !!(pmd_val(pmd) & _PAGE_PSE); +} + +struct page * +follow_huge_pmd(struct mm_struct *mm, unsigned long address, + pmd_t *pmd, int write) +{ + struct page *page; + + page = pte_page(*(pte_t *)pmd); + if (page) + page += ((address & ~HPAGE_MASK) >> PAGE_SHIFT); + return page; +} +#endif + +/* x86_64 also uses this file */ + +#ifdef HAVE_ARCH_HUGETLB_UNMAPPED_AREA +static unsigned long hugetlb_get_unmapped_area_bottomup(struct file *file, + unsigned long addr, unsigned long len, + unsigned long pgoff, unsigned long flags) +{ + struct mm_struct *mm = current->mm; + struct vm_area_struct *vma; + unsigned long start_addr; + + if (len > mm->cached_hole_size) { + start_addr = mm->free_area_cache; + } else { + start_addr = TASK_UNMAPPED_BASE; + mm->cached_hole_size = 0; + } + +full_search: + addr = ALIGN(start_addr, HPAGE_SIZE); + + for (vma = find_vma(mm, addr); ; vma = vma->vm_next) { + /* At this point: (!vma || addr < vma->vm_end). */ + if (TASK_SIZE - len < addr) { + /* + * Start a new search - just in case we missed + * some holes. + */ + if (start_addr != TASK_UNMAPPED_BASE) { + start_addr = TASK_UNMAPPED_BASE; + mm->cached_hole_size = 0; + goto full_search; + } + return -ENOMEM; + } + if (!vma || addr + len <= vma->vm_start) { + mm->free_area_cache = addr + len; + return addr; + } + if (addr + mm->cached_hole_size < vma->vm_start) + mm->cached_hole_size = vma->vm_start - addr; + addr = ALIGN(vma->vm_end, HPAGE_SIZE); + } +} + +static unsigned long hugetlb_get_unmapped_area_topdown(struct file *file, + unsigned long addr0, unsigned long len, + unsigned long pgoff, unsigned long flags) +{ + struct mm_struct *mm = current->mm; + struct vm_area_struct *vma, *prev_vma; + unsigned long base = mm->mmap_base, addr = addr0; + unsigned long largest_hole = mm->cached_hole_size; + int first_time = 1; + + /* don't allow allocations above current base */ + if (mm->free_area_cache > base) + mm->free_area_cache = base; + + if (len <= largest_hole) { + largest_hole = 0; + mm->free_area_cache = base; + } +try_again: + /* make sure it can fit in the remaining address space */ + if (mm->free_area_cache < len) + goto fail; + + /* either no address requested or cant fit in requested address hole */ + addr = (mm->free_area_cache - len) & HPAGE_MASK; + do { + /* + * Lookup failure means no vma is above this address, + * i.e. return with success: + */ + if (!(vma = find_vma_prev(mm, addr, &prev_vma))) + return addr; + + /* + * new region fits between prev_vma->vm_end and + * vma->vm_start, use it: + */ + if (addr + len <= vma->vm_start && + (!prev_vma || (addr >= prev_vma->vm_end))) { + /* remember the address as a hint for next time */ + mm->cached_hole_size = largest_hole; + return (mm->free_area_cache = addr); + } else { + /* pull free_area_cache down to the first hole */ + if (mm->free_area_cache == vma->vm_end) { + mm->free_area_cache = vma->vm_start; + mm->cached_hole_size = largest_hole; + } + } + + /* remember the largest hole we saw so far */ + if (addr + largest_hole < vma->vm_start) + largest_hole = vma->vm_start - addr; + + /* try just below the current vma->vm_start */ + addr = (vma->vm_start - len) & HPAGE_MASK; + } while (len <= vma->vm_start); + +fail: + /* + * if hint left us with no space for the requested + * mapping then try again: + */ + if (first_time) { + mm->free_area_cache = base; + largest_hole = 0; + first_time = 0; + goto try_again; + } + /* + * A failed mmap() very likely causes application failure, + * so fall back to the bottom-up function here. This scenario + * can happen with large stack limits and large mmap() + * allocations. + */ + mm->free_area_cache = TASK_UNMAPPED_BASE; + mm->cached_hole_size = ~0UL; + addr = hugetlb_get_unmapped_area_bottomup(file, addr0, + len, pgoff, flags); + + /* + * Restore the topdown base: + */ + mm->free_area_cache = base; + mm->cached_hole_size = ~0UL; + + return addr; +} + +unsigned long +hugetlb_get_unmapped_area(struct file *file, unsigned long addr, + unsigned long len, unsigned long pgoff, unsigned long flags) +{ + struct mm_struct *mm = current->mm; + struct vm_area_struct *vma; + + if (len & ~HPAGE_MASK) + return -EINVAL; + if (len > TASK_SIZE) + return -ENOMEM; + + if (flags & MAP_FIXED) { + if (prepare_hugepage_range(addr, len)) + return -EINVAL; + return addr; + } + + if (addr) { + addr = ALIGN(addr, HPAGE_SIZE); + vma = find_vma(mm, addr); + if (TASK_SIZE - len >= addr && + (!vma || addr + len <= vma->vm_start)) + return addr; + } + if (mm->get_unmapped_area == arch_get_unmapped_area) + return hugetlb_get_unmapped_area_bottomup(file, addr, len, + pgoff, flags); + else + return hugetlb_get_unmapped_area_topdown(file, addr, len, + pgoff, flags); +} + +#endif /*HAVE_ARCH_HUGETLB_UNMAPPED_AREA*/ + |