diff options
Diffstat (limited to 'mm/rmap.c')
| -rw-r--r-- | mm/rmap.c | 89 |
1 files changed, 85 insertions, 4 deletions
diff --git a/mm/rmap.c b/mm/rmap.c index a7d0f548263..92e6757f196 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -56,6 +56,7 @@ #include <linux/memcontrol.h> #include <linux/mmu_notifier.h> #include <linux/migrate.h> +#include <linux/hugetlb.h> #include <asm/tlbflush.h> @@ -315,7 +316,7 @@ void __init anon_vma_init(void) */ struct anon_vma *page_lock_anon_vma(struct page *page) { - struct anon_vma *anon_vma; + struct anon_vma *anon_vma, *root_anon_vma; unsigned long anon_mapping; rcu_read_lock(); @@ -326,8 +327,21 @@ struct anon_vma *page_lock_anon_vma(struct page *page) goto out; anon_vma = (struct anon_vma *) (anon_mapping - PAGE_MAPPING_ANON); - anon_vma_lock(anon_vma); - return anon_vma; + root_anon_vma = ACCESS_ONCE(anon_vma->root); + spin_lock(&root_anon_vma->lock); + + /* + * If this page is still mapped, then its anon_vma cannot have been + * freed. But if it has been unmapped, we have no security against + * the anon_vma structure being freed and reused (for another anon_vma: + * SLAB_DESTROY_BY_RCU guarantees that - so the spin_lock above cannot + * corrupt): with anon_vma_prepare() or anon_vma_fork() redirecting + * anon_vma->root before page_unlock_anon_vma() is called to unlock. + */ + if (page_mapped(page)) + return anon_vma; + + spin_unlock(&root_anon_vma->lock); out: rcu_read_unlock(); return NULL; @@ -350,6 +364,8 @@ vma_address(struct page *page, struct vm_area_struct *vma) pgoff_t pgoff = page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT); unsigned long address; + if (unlikely(is_vm_hugetlb_page(vma))) + pgoff = page->index << huge_page_order(page_hstate(page)); address = vma->vm_start + ((pgoff - vma->vm_pgoff) << PAGE_SHIFT); if (unlikely(address < vma->vm_start || address >= vma->vm_end)) { /* page should be within @vma mapping range */ @@ -365,7 +381,13 @@ vma_address(struct page *page, struct vm_area_struct *vma) unsigned long page_address_in_vma(struct page *page, struct vm_area_struct *vma) { if (PageAnon(page)) { - if (vma->anon_vma->root != page_anon_vma(page)->root) + struct anon_vma *page__anon_vma = page_anon_vma(page); + /* + * Note: swapoff's unuse_vma() is more efficient with this + * check, and needs it to match anon_vma when KSM is active. + */ + if (!vma->anon_vma || !page__anon_vma || + vma->anon_vma->root != page__anon_vma->root) return -EFAULT; } else if (page->mapping && !(vma->vm_flags & VM_NONLINEAR)) { if (!vma->vm_file || @@ -394,6 +416,12 @@ pte_t *page_check_address(struct page *page, struct mm_struct *mm, pte_t *pte; spinlock_t *ptl; + if (unlikely(PageHuge(page))) { + pte = huge_pte_offset(mm, address); + ptl = &mm->page_table_lock; + goto check; + } + pgd = pgd_offset(mm, address); if (!pgd_present(*pgd)) return NULL; @@ -414,6 +442,7 @@ pte_t *page_check_address(struct page *page, struct mm_struct *mm, } ptl = pte_lockptr(mm, pmd); +check: spin_lock(ptl); if (pte_present(*pte) && page_to_pfn(page) == pte_pfn(*pte)) { *ptlp = ptl; @@ -916,6 +945,12 @@ void page_remove_rmap(struct page *page) page_clear_dirty(page); set_page_dirty(page); } + /* + * Hugepages are not counted in NR_ANON_PAGES nor NR_FILE_MAPPED + * and not charged by memcg for now. + */ + if (unlikely(PageHuge(page))) + return; if (PageAnon(page)) { mem_cgroup_uncharge_page(page); __dec_zone_page_state(page, NR_ANON_PAGES); @@ -1524,3 +1559,49 @@ int rmap_walk(struct page *page, int (*rmap_one)(struct page *, return rmap_walk_file(page, rmap_one, arg); } #endif /* CONFIG_MIGRATION */ + +#ifdef CONFIG_HUGETLB_PAGE +/* + * The following three functions are for anonymous (private mapped) hugepages. + * Unlike common anonymous pages, anonymous hugepages have no accounting code + * and no lru code, because we handle hugepages differently from common pages. + */ +static void __hugepage_set_anon_rmap(struct page *page, + struct vm_area_struct *vma, unsigned long address, int exclusive) +{ + struct anon_vma *anon_vma = vma->anon_vma; + + BUG_ON(!anon_vma); + + if (PageAnon(page)) + return; + if (!exclusive) + anon_vma = anon_vma->root; + + anon_vma = (void *) anon_vma + PAGE_MAPPING_ANON; + page->mapping = (struct address_space *) anon_vma; + page->index = linear_page_index(vma, address); +} + +void hugepage_add_anon_rmap(struct page *page, + struct vm_area_struct *vma, unsigned long address) +{ + struct anon_vma *anon_vma = vma->anon_vma; + int first; + + BUG_ON(!PageLocked(page)); + BUG_ON(!anon_vma); + BUG_ON(address < vma->vm_start || address >= vma->vm_end); + first = atomic_inc_and_test(&page->_mapcount); + if (first) + __hugepage_set_anon_rmap(page, vma, address, 0); +} + +void hugepage_add_new_anon_rmap(struct page *page, + struct vm_area_struct *vma, unsigned long address) +{ + BUG_ON(address < vma->vm_start || address >= vma->vm_end); + atomic_set(&page->_mapcount, 0); + __hugepage_set_anon_rmap(page, vma, address, 1); +} +#endif /* CONFIG_HUGETLB_PAGE */ |