diff options
| -rw-r--r-- | include/linux/rmap.h | 5 | ||||
| -rw-r--r-- | mm/ksm.c | 4 | ||||
| -rw-r--r-- | mm/rmap.c | 48 |
3 files changed, 39 insertions, 18 deletions
diff --git a/include/linux/rmap.h b/include/linux/rmap.h index 616aa4d05f0a..2462458708cd 100644 --- a/include/linux/rmap.h +++ b/include/linux/rmap.h @@ -190,7 +190,7 @@ int page_referenced_one(struct page *, struct vm_area_struct *, int try_to_unmap(struct page *, enum ttu_flags flags); int try_to_unmap_one(struct page *, struct vm_area_struct *, - unsigned long address, enum ttu_flags flags); + unsigned long address, void *arg); /* * Called from mm/filemap_xip.c to unmap empty zero page @@ -256,9 +256,6 @@ struct rmap_walk_control { bool (*invalid_vma)(struct vm_area_struct *vma, void *arg); }; -/* - * Called by migrate.c to remove migration ptes, but might be used more later. - */ int rmap_walk(struct page *page, struct rmap_walk_control *rwc); #else /* !CONFIG_MMU */ @@ -1982,7 +1982,7 @@ again: continue; ret = try_to_unmap_one(page, vma, - rmap_item->address, flags); + rmap_item->address, (void *)flags); if (ret != SWAP_AGAIN || !page_mapped(page)) { anon_vma_unlock_read(anon_vma); goto out; @@ -1996,7 +1996,6 @@ out: return ret; } -#ifdef CONFIG_MIGRATION int rmap_walk_ksm(struct page *page, struct rmap_walk_control *rwc) { struct stable_node *stable_node; @@ -2054,6 +2053,7 @@ out: return ret; } +#ifdef CONFIG_MIGRATION void ksm_migrate_page(struct page *newpage, struct page *oldpage) { struct stable_node *stable_node; diff --git a/mm/rmap.c b/mm/rmap.c index 97bf8f0396f8..b3263cb32361 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -1179,15 +1179,18 @@ out: /* * Subfunctions of try_to_unmap: try_to_unmap_one called * repeatedly from try_to_unmap_ksm, try_to_unmap_anon or try_to_unmap_file. + * + * @arg: enum ttu_flags will be passed to this argument */ int try_to_unmap_one(struct page *page, struct vm_area_struct *vma, - unsigned long address, enum ttu_flags flags) + unsigned long address, void *arg) { struct mm_struct *mm = vma->vm_mm; pte_t *pte; pte_t pteval; spinlock_t *ptl; int ret = SWAP_AGAIN; + enum ttu_flags flags = (enum ttu_flags)arg; pte = page_check_address(page, mm, address, &ptl, 0); if (!pte) @@ -1513,6 +1516,11 @@ bool is_vma_temporary_stack(struct vm_area_struct *vma) return false; } +static bool invalid_migration_vma(struct vm_area_struct *vma, void *arg) +{ + return is_vma_temporary_stack(vma); +} + /** * try_to_unmap_anon - unmap or unlock anonymous page using the object-based * rmap method @@ -1558,7 +1566,7 @@ static int try_to_unmap_anon(struct page *page, enum ttu_flags flags) continue; address = vma_address(page, vma); - ret = try_to_unmap_one(page, vma, address, flags); + ret = try_to_unmap_one(page, vma, address, (void *)flags); if (ret != SWAP_AGAIN || !page_mapped(page)) break; } @@ -1592,7 +1600,7 @@ static int try_to_unmap_file(struct page *page, enum ttu_flags flags) mutex_lock(&mapping->i_mmap_mutex); vma_interval_tree_foreach(vma, &mapping->i_mmap, pgoff, pgoff) { unsigned long address = vma_address(page, vma); - ret = try_to_unmap_one(page, vma, address, flags); + ret = try_to_unmap_one(page, vma, address, (void *)flags); if (ret != SWAP_AGAIN || !page_mapped(page)) goto out; } @@ -1614,6 +1622,11 @@ out: return ret; } +static int page_not_mapped(struct page *page) +{ + return !page_mapped(page); +}; + /** * try_to_unmap - try to remove all page table mappings to a page * @page: the page to get unmapped @@ -1631,16 +1644,29 @@ out: int try_to_unmap(struct page *page, enum ttu_flags flags) { int ret; + struct rmap_walk_control rwc = { + .rmap_one = try_to_unmap_one, + .arg = (void *)flags, + .done = page_not_mapped, + .file_nonlinear = try_to_unmap_nonlinear, + .anon_lock = page_lock_anon_vma_read, + }; - BUG_ON(!PageLocked(page)); VM_BUG_ON(!PageHuge(page) && PageTransHuge(page)); - if (unlikely(PageKsm(page))) - ret = try_to_unmap_ksm(page, flags); - else if (PageAnon(page)) - ret = try_to_unmap_anon(page, flags); - else - ret = try_to_unmap_file(page, flags); + /* + * During exec, a temporary VMA is setup and later moved. + * The VMA is moved under the anon_vma lock but not the + * page tables leading to a race where migration cannot + * find the migration ptes. Rather than increasing the + * locking requirements of exec(), migration skips + * temporary VMAs until after exec() completes. + */ + if (flags & TTU_MIGRATION && !PageKsm(page) && PageAnon(page)) + rwc.invalid_vma = invalid_migration_vma; + + ret = rmap_walk(page, &rwc); + if (ret != SWAP_MLOCK && !page_mapped(page)) ret = SWAP_SUCCESS; return ret; @@ -1683,7 +1709,6 @@ void __put_anon_vma(struct anon_vma *anon_vma) anon_vma_free(anon_vma); } -#ifdef CONFIG_MIGRATION static struct anon_vma *rmap_walk_anon_lock(struct page *page, struct rmap_walk_control *rwc) { @@ -1785,7 +1810,6 @@ int rmap_walk(struct page *page, struct rmap_walk_control *rwc) else return rmap_walk_file(page, rwc); } -#endif /* CONFIG_MIGRATION */ #ifdef CONFIG_HUGETLB_PAGE /* |