diff options
Diffstat (limited to 'mm/pagewalk.c')
| -rw-r--r-- | mm/pagewalk.c | 171 |
1 files changed, 144 insertions, 27 deletions
diff --git a/mm/pagewalk.c b/mm/pagewalk.c index 1cf1417ef8b..2beeabf502c 100644 --- a/mm/pagewalk.c +++ b/mm/pagewalk.c @@ -1,26 +1,31 @@ #include <linux/mm.h> #include <linux/highmem.h> #include <linux/sched.h> +#include <linux/hugetlb.h> static int walk_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end, - const struct mm_walk *walk, void *private) + struct mm_walk *walk) { pte_t *pte; int err = 0; pte = pte_offset_map(pmd, addr); - do { - err = walk->pte_entry(pte, addr, addr + PAGE_SIZE, private); + for (;;) { + err = walk->pte_entry(pte, addr, addr + PAGE_SIZE, walk); if (err) break; - } while (pte++, addr += PAGE_SIZE, addr != end); + addr += PAGE_SIZE; + if (addr == end) + break; + pte++; + } pte_unmap(pte); return err; } static int walk_pmd_range(pud_t *pud, unsigned long addr, unsigned long end, - const struct mm_walk *walk, void *private) + struct mm_walk *walk) { pmd_t *pmd; unsigned long next; @@ -28,18 +33,35 @@ static int walk_pmd_range(pud_t *pud, unsigned long addr, unsigned long end, pmd = pmd_offset(pud, addr); do { +again: next = pmd_addr_end(addr, end); - if (pmd_none_or_clear_bad(pmd)) { + if (pmd_none(*pmd)) { if (walk->pte_hole) - err = walk->pte_hole(addr, next, private); + err = walk->pte_hole(addr, next, walk); if (err) break; continue; } + /* + * This implies that each ->pmd_entry() handler + * needs to know about pmd_trans_huge() pmds + */ if (walk->pmd_entry) - err = walk->pmd_entry(pmd, addr, next, private); - if (!err && walk->pte_entry) - err = walk_pte_range(pmd, addr, next, walk, private); + err = walk->pmd_entry(pmd, addr, next, walk); + if (err) + break; + + /* + * Check this here so we only break down trans_huge + * pages when we _need_ to + */ + if (!walk->pte_entry) + continue; + + split_huge_page_pmd_mm(walk->mm, addr, pmd); + if (pmd_none_or_trans_huge_or_clear_bad(pmd)) + goto again; + err = walk_pte_range(pmd, addr, next, walk); if (err) break; } while (pmd++, addr = next, addr != end); @@ -48,7 +70,7 @@ static int walk_pmd_range(pud_t *pud, unsigned long addr, unsigned long end, } static int walk_pud_range(pgd_t *pgd, unsigned long addr, unsigned long end, - const struct mm_walk *walk, void *private) + struct mm_walk *walk) { pud_t *pud; unsigned long next; @@ -59,15 +81,15 @@ static int walk_pud_range(pgd_t *pgd, unsigned long addr, unsigned long end, next = pud_addr_end(addr, end); if (pud_none_or_clear_bad(pud)) { if (walk->pte_hole) - err = walk->pte_hole(addr, next, private); + err = walk->pte_hole(addr, next, walk); if (err) break; continue; } if (walk->pud_entry) - err = walk->pud_entry(pud, addr, next, private); + err = walk->pud_entry(pud, addr, next, walk); if (!err && (walk->pmd_entry || walk->pte_entry)) - err = walk_pmd_range(pud, addr, next, walk, private); + err = walk_pmd_range(pud, addr, next, walk); if (err) break; } while (pud++, addr = next, addr != end); @@ -75,31 +97,75 @@ static int walk_pud_range(pgd_t *pgd, unsigned long addr, unsigned long end, return err; } +#ifdef CONFIG_HUGETLB_PAGE +static unsigned long hugetlb_entry_end(struct hstate *h, unsigned long addr, + unsigned long end) +{ + unsigned long boundary = (addr & huge_page_mask(h)) + huge_page_size(h); + return boundary < end ? boundary : end; +} + +static int walk_hugetlb_range(struct vm_area_struct *vma, + unsigned long addr, unsigned long end, + struct mm_walk *walk) +{ + struct hstate *h = hstate_vma(vma); + unsigned long next; + unsigned long hmask = huge_page_mask(h); + pte_t *pte; + int err = 0; + + do { + next = hugetlb_entry_end(h, addr, end); + pte = huge_pte_offset(walk->mm, addr & hmask); + if (pte && walk->hugetlb_entry) + err = walk->hugetlb_entry(pte, hmask, addr, next, walk); + if (err) + return err; + } while (addr = next, addr != end); + + return 0; +} + +#else /* CONFIG_HUGETLB_PAGE */ +static int walk_hugetlb_range(struct vm_area_struct *vma, + unsigned long addr, unsigned long end, + struct mm_walk *walk) +{ + return 0; +} + +#endif /* CONFIG_HUGETLB_PAGE */ + + + /** * walk_page_range - walk a memory map's page tables with a callback - * @mm: memory map to walk * @addr: starting address * @end: ending address * @walk: set of callbacks to invoke for each level of the tree - * @private: private data passed to the callback function * * Recursively walk the page table for the memory area in a VMA, * calling supplied callbacks. Callbacks are called in-order (first * PGD, first PUD, first PMD, first PTE, second PTE... second PMD, * etc.). If lower-level callbacks are omitted, walking depth is reduced. * - * Each callback receives an entry pointer, the start and end of the - * associated range, and a caller-supplied private data pointer. + * Each callback receives an entry pointer and the start and end of the + * associated range, and a copy of the original mm_walk for access to + * the ->private or ->mm fields. * - * No locks are taken, but the bottom level iterator will map PTE + * Usually no locks are taken, but splitting transparent huge page may + * take page table lock. And the bottom level iterator will map PTE * directories from highmem if necessary. * * If any callback returns a non-zero value, the walk is aborted and * the return value is propagated back to the caller. Otherwise 0 is returned. + * + * walk->mm->mmap_sem must be held for at least read if walk->hugetlb_entry + * is !NULL. */ -int walk_page_range(const struct mm_struct *mm, - unsigned long addr, unsigned long end, - const struct mm_walk *walk, void *private) +int walk_page_range(unsigned long addr, unsigned long end, + struct mm_walk *walk) { pgd_t *pgd; unsigned long next; @@ -108,24 +174,75 @@ int walk_page_range(const struct mm_struct *mm, if (addr >= end) return err; - pgd = pgd_offset(mm, addr); + if (!walk->mm) + return -EINVAL; + + VM_BUG_ON(!rwsem_is_locked(&walk->mm->mmap_sem)); + + pgd = pgd_offset(walk->mm, addr); do { + struct vm_area_struct *vma = NULL; + next = pgd_addr_end(addr, end); + + /* + * This function was not intended to be vma based. + * But there are vma special cases to be handled: + * - hugetlb vma's + * - VM_PFNMAP vma's + */ + vma = find_vma(walk->mm, addr); + if (vma) { + /* + * There are no page structures backing a VM_PFNMAP + * range, so do not allow split_huge_page_pmd(). + */ + if ((vma->vm_start <= addr) && + (vma->vm_flags & VM_PFNMAP)) { + next = vma->vm_end; + pgd = pgd_offset(walk->mm, next); + continue; + } + /* + * Handle hugetlb vma individually because pagetable + * walk for the hugetlb page is dependent on the + * architecture and we can't handled it in the same + * manner as non-huge pages. + */ + if (walk->hugetlb_entry && (vma->vm_start <= addr) && + is_vm_hugetlb_page(vma)) { + if (vma->vm_end < next) + next = vma->vm_end; + /* + * Hugepage is very tightly coupled with vma, + * so walk through hugetlb entries within a + * given vma. + */ + err = walk_hugetlb_range(vma, addr, next, walk); + if (err) + break; + pgd = pgd_offset(walk->mm, next); + continue; + } + } + if (pgd_none_or_clear_bad(pgd)) { if (walk->pte_hole) - err = walk->pte_hole(addr, next, private); + err = walk->pte_hole(addr, next, walk); if (err) break; + pgd++; continue; } if (walk->pgd_entry) - err = walk->pgd_entry(pgd, addr, next, private); + err = walk->pgd_entry(pgd, addr, next, walk); if (!err && (walk->pud_entry || walk->pmd_entry || walk->pte_entry)) - err = walk_pud_range(pgd, addr, next, walk, private); + err = walk_pud_range(pgd, addr, next, walk); if (err) break; - } while (pgd++, addr = next, addr != end); + pgd++; + } while (addr = next, addr < end); return err; } |