X-Git-Url: http://ftp.safe.ca/?p=safe%2Fjmp%2Flinux-2.6;a=blobdiff_plain;f=mm%2Fmigrate.c;h=367272d0442311c9ec4e38f3ae2c99618ea04f63;hp=55bd355d170d055907c407f0c93d98dcb6e9e555;hb=af8e3354b4bbd1ee5a3a55d11a5e1fe37e77f0ba;hpb=cde53535991fbb5c34a1566f25955297c1487b8d diff --git a/mm/migrate.c b/mm/migrate.c index 55bd355..367272d 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -30,42 +30,13 @@ #include #include #include +#include #include "internal.h" #define lru_to_page(_head) (list_entry((_head)->prev, struct page, lru)) /* - * Isolate one page from the LRU lists. If successful put it onto - * the indicated list with elevated page count. - * - * Result: - * -EBUSY: page not on LRU list - * 0: page removed from LRU list and added to the specified list. - */ -int isolate_lru_page(struct page *page, struct list_head *pagelist) -{ - int ret = -EBUSY; - - if (PageLRU(page)) { - struct zone *zone = page_zone(page); - - spin_lock_irq(&zone->lru_lock); - if (PageLRU(page) && get_page_unless_zero(page)) { - ret = 0; - ClearPageLRU(page); - if (PageActive(page)) - del_page_from_active_list(zone, page); - else - del_page_from_inactive_list(zone, page); - list_add_tail(&page->lru, pagelist); - } - spin_unlock_irq(&zone->lru_lock); - } - return ret; -} - -/* * migrate_prep() needs to be called before we start compiling a list of pages * to be migrated using isolate_lru_page(). */ @@ -82,23 +53,9 @@ int migrate_prep(void) return 0; } -static inline void move_to_lru(struct page *page) -{ - if (PageActive(page)) { - /* - * lru_cache_add_active checks that - * the PG_active bit is off. - */ - ClearPageActive(page); - lru_cache_add_active(page); - } else { - lru_cache_add(page); - } - put_page(page); -} - /* - * Add isolated pages on the list back to the LRU. + * Add isolated pages on the list back to the LRU under page lock + * to avoid leaking evictable pages back onto unevictable list. * * returns the number of pages put back. */ @@ -110,7 +67,9 @@ int putback_lru_pages(struct list_head *l) list_for_each_entry_safe(page, page2, l, lru) { list_del(&page->lru); - move_to_lru(page); + dec_zone_page_state(page, NR_ISOLATED_ANON + + page_is_file_cache(page)); + putback_lru_page(page); count++; } return count; @@ -164,20 +123,6 @@ static void remove_migration_pte(struct vm_area_struct *vma, if (!is_migration_entry(entry) || migration_entry_to_page(entry) != old) goto out; - /* - * Yes, ignore the return value from a GFP_ATOMIC mem_cgroup_charge. - * Failure is not an option here: we're now expected to remove every - * migration pte, and will cause crashes otherwise. Normally this - * is not an issue: mem_cgroup_prepare_migration bumped up the old - * page_cgroup count for safety, that's now attached to the new page, - * so this charge should just be another incrementation of the count, - * to keep in balance with rmap.c's mem_cgroup_uncharging. But if - * there's been a force_empty, those reference counts may no longer - * be reliable, and this charge can actually fail: oh well, we don't - * make the situation any worse by proceeding as if it had succeeded. - */ - mem_cgroup_charge(new, mm, GFP_ATOMIC); - get_page(new); pte = pte_mkold(mk_pte(new, vma->vm_page_prot)); if (is_write_migration_entry(entry)) @@ -204,7 +149,7 @@ out: static void remove_file_migration_ptes(struct page *old, struct page *new) { struct vm_area_struct *vma; - struct address_space *mapping = page_mapping(new); + struct address_space *mapping = new->mapping; struct prio_tree_iter iter; pgoff_t pgoff = new->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT); @@ -227,17 +172,14 @@ static void remove_anon_migration_ptes(struct page *old, struct page *new) { struct anon_vma *anon_vma; struct vm_area_struct *vma; - unsigned long mapping; - - mapping = (unsigned long)new->mapping; - - if (!mapping || (mapping & PAGE_MAPPING_ANON) == 0) - return; /* * We hold the mmap_sem lock. So no need to call page_lock_anon_vma. */ - anon_vma = (struct anon_vma *) (mapping - PAGE_MAPPING_ANON); + anon_vma = page_anon_vma(new); + if (!anon_vma) + return; + spin_lock(&anon_vma->lock); list_for_each_entry(vma, &anon_vma->head, anon_vma_node) @@ -284,7 +226,15 @@ void migration_entry_wait(struct mm_struct *mm, pmd_t *pmd, page = migration_entry_to_page(entry); - get_page(page); + /* + * Once radix-tree replacement of page migration started, page_count + * *must* be zero. And, we don't want to call wait_on_page_locked() + * against a page without get_page(). + * So, we use get_page_unless_zero(), here. Even failed, page fault + * will occur again. + */ + if (!get_page_unless_zero(page)) + goto out; pte_unmap_unlock(ptep, ptl); wait_on_page_locked(page); put_page(page); @@ -299,11 +249,12 @@ out: * The number of remaining references must be: * 1 for anonymous pages without a mapping * 2 for pages with a mapping - * 3 for pages with a mapping and PagePrivate set. + * 3 for pages with a mapping and PagePrivate/PagePrivate2 set. */ static int migrate_page_move_mapping(struct address_space *mapping, struct page *newpage, struct page *page) { + int expected_count; void **pslot; if (!mapping) { @@ -313,14 +264,20 @@ static int migrate_page_move_mapping(struct address_space *mapping, return 0; } - write_lock_irq(&mapping->tree_lock); + spin_lock_irq(&mapping->tree_lock); pslot = radix_tree_lookup_slot(&mapping->page_tree, page_index(page)); - if (page_count(page) != 2 + !!PagePrivate(page) || + expected_count = 2 + page_has_private(page); + if (page_count(page) != expected_count || (struct page *)radix_tree_deref_slot(pslot) != page) { - write_unlock_irq(&mapping->tree_lock); + spin_unlock_irq(&mapping->tree_lock); + return -EAGAIN; + } + + if (!page_freeze_refs(page, expected_count)) { + spin_unlock_irq(&mapping->tree_lock); return -EAGAIN; } @@ -328,15 +285,14 @@ static int migrate_page_move_mapping(struct address_space *mapping, * Now we know that no one else is looking at the page. */ get_page(newpage); /* add cache reference */ -#ifdef CONFIG_SWAP if (PageSwapCache(page)) { SetPageSwapCache(newpage); set_page_private(newpage, page_private(page)); } -#endif radix_tree_replace_slot(pslot, newpage); + page_unfreeze_refs(page, expected_count); /* * Drop cache reference from old page. * We know this isn't the last reference. @@ -355,8 +311,11 @@ static int migrate_page_move_mapping(struct address_space *mapping, */ __dec_zone_page_state(page, NR_FILE_PAGES); __inc_zone_page_state(newpage, NR_FILE_PAGES); - - write_unlock_irq(&mapping->tree_lock); + if (PageSwapBacked(page)) { + __dec_zone_page_state(page, NR_SHMEM); + __inc_zone_page_state(newpage, NR_SHMEM); + } + spin_unlock_irq(&mapping->tree_lock); return 0; } @@ -366,6 +325,8 @@ static int migrate_page_move_mapping(struct address_space *mapping, */ static void migrate_page_copy(struct page *newpage, struct page *page) { + int anon; + copy_highpage(newpage, page); if (PageError(page)) @@ -374,8 +335,11 @@ static void migrate_page_copy(struct page *newpage, struct page *page) SetPageReferenced(newpage); if (PageUptodate(page)) SetPageUptodate(newpage); - if (PageActive(page)) + if (TestClearPageActive(page)) { + VM_BUG_ON(PageUnevictable(page)); SetPageActive(newpage); + } else + unevictable_migrate_page(newpage, page); if (PageChecked(page)) SetPageChecked(newpage); if (PageMappedToDisk(page)) @@ -393,12 +357,13 @@ static void migrate_page_copy(struct page *newpage, struct page *page) __set_page_dirty_nobuffers(newpage); } -#ifdef CONFIG_SWAP + mlock_migrate_page(newpage, page); + ClearPageSwapCache(page); -#endif - ClearPageActive(page); ClearPagePrivate(page); set_page_private(page, 0); + /* page->mapping contains a flag for PageAnon() */ + anon = PageAnon(page); page->mapping = NULL; /* @@ -423,7 +388,7 @@ EXPORT_SYMBOL(fail_migrate_page); /* * Common logic to directly migrate a single page suitable for - * pages that do not use PagePrivate. + * pages that do not use PagePrivate/PagePrivate2. * * Pages are locked upon entry and exit. */ @@ -538,15 +503,12 @@ static int writeout(struct address_space *mapping, struct page *page) remove_migration_ptes(page, page); rc = mapping->a_ops->writepage(page, &wbc); - if (rc < 0) - /* I/O Error writing */ - return -EIO; if (rc != AOP_WRITEPAGE_ACTIVATE) /* unlocked. Relock */ lock_page(page); - return -EAGAIN; + return (rc < 0) ? -EIO : -EAGAIN; } /* @@ -562,7 +524,7 @@ static int fallback_migrate_page(struct address_space *mapping, * Buffers may be managed in a filesystem specific way. * We must have no buffers or drop them. */ - if (PagePrivate(page) && + if (page_has_private(page) && !try_to_release_page(page, GFP_KERNEL)) return -EAGAIN; @@ -575,6 +537,10 @@ static int fallback_migrate_page(struct address_space *mapping, * * The new page will have replaced the old page if this function * is successful. + * + * Return value: + * < 0 - error code + * == 0 - success */ static int move_to_new_page(struct page *newpage, struct page *page) { @@ -586,12 +552,14 @@ static int move_to_new_page(struct page *newpage, struct page *page) * establishing additional references. We are the only one * holding a reference to the new page at this point. */ - if (TestSetPageLocked(newpage)) + if (!trylock_page(newpage)) BUG(); /* Prepare mapping for the new page.*/ newpage->index = page->index; newpage->mapping = page->mapping; + if (PageSwapBacked(page)) + SetPageSwapBacked(newpage); mapping = page_mapping(page); if (!mapping) @@ -610,7 +578,6 @@ static int move_to_new_page(struct page *newpage, struct page *page) rc = fallback_migrate_page(mapping, newpage, page); if (!rc) { - mem_cgroup_page_migration(page, newpage); remove_migration_ptes(page, newpage); } else newpage->mapping = NULL; @@ -632,24 +599,36 @@ static int unmap_and_move(new_page_t get_new_page, unsigned long private, struct page *newpage = get_new_page(page, private, &result); int rcu_locked = 0; int charge = 0; + struct mem_cgroup *mem = NULL; if (!newpage) return -ENOMEM; - if (page_count(page) == 1) + if (page_count(page) == 1) { /* page was freed from under us. So we are done. */ goto move_newpage; + } + /* prepare cgroup just returns 0 or -ENOMEM */ rc = -EAGAIN; - if (TestSetPageLocked(page)) { + + if (!trylock_page(page)) { if (!force) goto move_newpage; lock_page(page); } + /* charge against new page */ + charge = mem_cgroup_prepare_migration(page, &mem); + if (charge == -ENOMEM) { + rc = -ENOMEM; + goto unlock; + } + BUG_ON(charge); + if (PageWriteback(page)) { if (!force) - goto unlock; + goto uncharge; wait_on_page_writeback(page); } /* @@ -678,7 +657,7 @@ static int unmap_and_move(new_page_t get_new_page, unsigned long private, * free the metadata, so the page can be freed. */ if (!page->mapping) { - if (!PageAnon(page) && PagePrivate(page)) { + if (!PageAnon(page) && page_has_private(page)) { /* * Go direct to try_to_free_buffers() here because * a) that's what try_to_release_page() would do anyway @@ -687,29 +666,27 @@ static int unmap_and_move(new_page_t get_new_page, unsigned long private, * needs to be effective. */ try_to_free_buffers(page); + goto rcu_unlock; } - goto rcu_unlock; + goto skip_unmap; } - charge = mem_cgroup_prepare_migration(page); /* Establish migration ptes or remove ptes */ - try_to_unmap(page, 1); + try_to_unmap(page, TTU_MIGRATION|TTU_IGNORE_MLOCK|TTU_IGNORE_ACCESS); +skip_unmap: if (!page_mapped(page)) rc = move_to_new_page(newpage, page); - if (rc) { + if (rc) remove_migration_ptes(page, page); - if (charge) - mem_cgroup_end_migration(page); - } else if (charge) - mem_cgroup_end_migration(newpage); rcu_unlock: if (rcu_locked) rcu_read_unlock(); - +uncharge: + if (!charge) + mem_cgroup_end_migration(mem, page, newpage); unlock: - unlock_page(page); if (rc != -EAGAIN) { @@ -720,15 +697,19 @@ unlock: * restored. */ list_del(&page->lru); - move_to_lru(page); + dec_zone_page_state(page, NR_ISOLATED_ANON + + page_is_file_cache(page)); + putback_lru_page(page); } move_newpage: + /* * Move the new page to the LRU. If migration was not successful * then this will free the page. */ - move_to_lru(newpage); + putback_lru_page(newpage); + if (result) { if (rc) *result = rc; @@ -827,7 +808,7 @@ static struct page *new_page_node(struct page *p, unsigned long private, *result = &pm->status; - return alloc_pages_node(pm->node, + return alloc_pages_exact_node(pm->node, GFP_HIGHUSER_MOVABLE | GFP_THISNODE, 0); } @@ -835,9 +816,11 @@ static struct page *new_page_node(struct page *p, unsigned long private, * Move a set of pages as indicated in the pm array. The addr * field must be set to the virtual address of the page to be moved * and the node number must contain a valid target node. + * The pm array ends with node = MAX_NUMNODES. */ -static int do_move_pages(struct mm_struct *mm, struct page_to_node *pm, - int migrate_all) +static int do_move_page_to_node_array(struct mm_struct *mm, + struct page_to_node *pm, + int migrate_all) { int err; struct page_to_node *pp; @@ -848,17 +831,10 @@ static int do_move_pages(struct mm_struct *mm, struct page_to_node *pm, /* * Build a list of pages to migrate */ - migrate_prep(); for (pp = pm; pp->node != MAX_NUMNODES; pp++) { struct vm_area_struct *vma; struct page *page; - /* - * A valid page pointer that will not match any of the - * pages that will be moved. - */ - pp->page = ZERO_PAGE(0); - err = -EFAULT; vma = find_vma(mm, pp->addr); if (!vma || !vma_migratable(vma)) @@ -891,7 +867,12 @@ static int do_move_pages(struct mm_struct *mm, struct page_to_node *pm, !migrate_all) goto put_and_set; - err = isolate_lru_page(page, &pagelist); + err = isolate_lru_page(page); + if (!err) { + list_add_tail(&page->lru, &pagelist); + inc_zone_page_state(page, NR_ISOLATED_ANON + + page_is_file_cache(page)); + } put_and_set: /* * Either remove the duplicate refcount from @@ -903,36 +884,123 @@ set_status: pp->status = err; } + err = 0; if (!list_empty(&pagelist)) err = migrate_pages(&pagelist, new_page_node, (unsigned long)pm); - else - err = -ENOENT; up_read(&mm->mmap_sem); return err; } /* - * Determine the nodes of a list of pages. The addr in the pm array - * must have been set to the virtual address of which we want to determine - * the node number. + * Migrate an array of page address onto an array of nodes and fill + * the corresponding array of status. + */ +static int do_pages_move(struct mm_struct *mm, struct task_struct *task, + unsigned long nr_pages, + const void __user * __user *pages, + const int __user *nodes, + int __user *status, int flags) +{ + struct page_to_node *pm; + nodemask_t task_nodes; + unsigned long chunk_nr_pages; + unsigned long chunk_start; + int err; + + task_nodes = cpuset_mems_allowed(task); + + err = -ENOMEM; + pm = (struct page_to_node *)__get_free_page(GFP_KERNEL); + if (!pm) + goto out; + + migrate_prep(); + + /* + * Store a chunk of page_to_node array in a page, + * but keep the last one as a marker + */ + chunk_nr_pages = (PAGE_SIZE / sizeof(struct page_to_node)) - 1; + + for (chunk_start = 0; + chunk_start < nr_pages; + chunk_start += chunk_nr_pages) { + int j; + + if (chunk_start + chunk_nr_pages > nr_pages) + chunk_nr_pages = nr_pages - chunk_start; + + /* fill the chunk pm with addrs and nodes from user-space */ + for (j = 0; j < chunk_nr_pages; j++) { + const void __user *p; + int node; + + err = -EFAULT; + if (get_user(p, pages + j + chunk_start)) + goto out_pm; + pm[j].addr = (unsigned long) p; + + if (get_user(node, nodes + j + chunk_start)) + goto out_pm; + + err = -ENODEV; + if (!node_state(node, N_HIGH_MEMORY)) + goto out_pm; + + err = -EACCES; + if (!node_isset(node, task_nodes)) + goto out_pm; + + pm[j].node = node; + } + + /* End marker for this chunk */ + pm[chunk_nr_pages].node = MAX_NUMNODES; + + /* Migrate this chunk */ + err = do_move_page_to_node_array(mm, pm, + flags & MPOL_MF_MOVE_ALL); + if (err < 0) + goto out_pm; + + /* Return status information */ + for (j = 0; j < chunk_nr_pages; j++) + if (put_user(pm[j].status, status + j + chunk_start)) { + err = -EFAULT; + goto out_pm; + } + } + err = 0; + +out_pm: + free_page((unsigned long)pm); +out: + return err; +} + +/* + * Determine the nodes of an array of pages and store it in an array of status. */ -static int do_pages_stat(struct mm_struct *mm, struct page_to_node *pm) +static void do_pages_stat_array(struct mm_struct *mm, unsigned long nr_pages, + const void __user **pages, int *status) { + unsigned long i; + down_read(&mm->mmap_sem); - for ( ; pm->node != MAX_NUMNODES; pm++) { + for (i = 0; i < nr_pages; i++) { + unsigned long addr = (unsigned long)(*pages); struct vm_area_struct *vma; struct page *page; - int err; + int err = -EFAULT; - err = -EFAULT; - vma = find_vma(mm, pm->addr); + vma = find_vma(mm, addr); if (!vma) goto set_status; - page = follow_page(vma, pm->addr, 0); + page = follow_page(vma, addr, 0); err = PTR_ERR(page); if (IS_ERR(page)) @@ -945,28 +1013,68 @@ static int do_pages_stat(struct mm_struct *mm, struct page_to_node *pm) err = page_to_nid(page); set_status: - pm->status = err; + *status = err; + + pages++; + status++; } up_read(&mm->mmap_sem); - return 0; +} + +/* + * Determine the nodes of a user array of pages and store it in + * a user array of status. + */ +static int do_pages_stat(struct mm_struct *mm, unsigned long nr_pages, + const void __user * __user *pages, + int __user *status) +{ +#define DO_PAGES_STAT_CHUNK_NR 16 + const void __user *chunk_pages[DO_PAGES_STAT_CHUNK_NR]; + int chunk_status[DO_PAGES_STAT_CHUNK_NR]; + unsigned long i, chunk_nr = DO_PAGES_STAT_CHUNK_NR; + int err; + + for (i = 0; i < nr_pages; i += chunk_nr) { + if (chunk_nr > nr_pages - i) + chunk_nr = nr_pages - i; + + err = copy_from_user(chunk_pages, &pages[i], + chunk_nr * sizeof(*chunk_pages)); + if (err) { + err = -EFAULT; + goto out; + } + + do_pages_stat_array(mm, chunk_nr, chunk_pages, chunk_status); + + err = copy_to_user(&status[i], chunk_status, + chunk_nr * sizeof(*chunk_status)); + if (err) { + err = -EFAULT; + goto out; + } + } + err = 0; + +out: + return err; } /* * Move a list of pages in the address space of the currently executing * process. */ -asmlinkage long sys_move_pages(pid_t pid, unsigned long nr_pages, - const void __user * __user *pages, - const int __user *nodes, - int __user *status, int flags) +SYSCALL_DEFINE6(move_pages, pid_t, pid, unsigned long, nr_pages, + const void __user * __user *, pages, + const int __user *, nodes, + int __user *, status, int, flags) { - int err = 0; - int i; + const struct cred *cred = current_cred(), *tcred; struct task_struct *task; - nodemask_t task_nodes; struct mm_struct *mm; - struct page_to_node *pm = NULL; + int err; /* Check flags */ if (flags & ~(MPOL_MF_MOVE|MPOL_MF_MOVE_ALL)) @@ -994,83 +1102,32 @@ asmlinkage long sys_move_pages(pid_t pid, unsigned long nr_pages, * capabilities, superuser privileges or the same * userid as the target process. */ - if ((current->euid != task->suid) && (current->euid != task->uid) && - (current->uid != task->suid) && (current->uid != task->uid) && + rcu_read_lock(); + tcred = __task_cred(task); + if (cred->euid != tcred->suid && cred->euid != tcred->uid && + cred->uid != tcred->suid && cred->uid != tcred->uid && !capable(CAP_SYS_NICE)) { + rcu_read_unlock(); err = -EPERM; - goto out2; + goto out; } + rcu_read_unlock(); err = security_task_movememory(task); if (err) - goto out2; - - - task_nodes = cpuset_mems_allowed(task); - - /* Limit nr_pages so that the multiplication may not overflow */ - if (nr_pages >= ULONG_MAX / sizeof(struct page_to_node) - 1) { - err = -E2BIG; - goto out2; - } - - pm = vmalloc((nr_pages + 1) * sizeof(struct page_to_node)); - if (!pm) { - err = -ENOMEM; - goto out2; - } - - /* - * Get parameters from user space and initialize the pm - * array. Return various errors if the user did something wrong. - */ - for (i = 0; i < nr_pages; i++) { - const void __user *p; - - err = -EFAULT; - if (get_user(p, pages + i)) - goto out; - - pm[i].addr = (unsigned long)p; - if (nodes) { - int node; - - if (get_user(node, nodes + i)) - goto out; - - err = -ENODEV; - if (!node_state(node, N_HIGH_MEMORY)) - goto out; - - err = -EACCES; - if (!node_isset(node, task_nodes)) - goto out; + goto out; - pm[i].node = node; - } else - pm[i].node = 0; /* anything to not match MAX_NUMNODES */ + if (nodes) { + err = do_pages_move(mm, task, nr_pages, pages, nodes, status, + flags); + } else { + err = do_pages_stat(mm, nr_pages, pages, status); } - /* End marker */ - pm[nr_pages].node = MAX_NUMNODES; - - if (nodes) - err = do_move_pages(mm, pm, flags & MPOL_MF_MOVE_ALL); - else - err = do_pages_stat(mm, pm); - - if (err >= 0) - /* Return status information */ - for (i = 0; i < nr_pages; i++) - if (put_user(pm[i].status, status + i)) - err = -EFAULT; out: - vfree(pm); -out2: mmput(mm); return err; } -#endif /* * Call migration functions in the vma_ops that may prepare @@ -1083,7 +1140,7 @@ int migrate_vmas(struct mm_struct *mm, const nodemask_t *to, struct vm_area_struct *vma; int err = 0; - for(vma = mm->mmap; vma->vm_next && !err; vma = vma->vm_next) { + for (vma = mm->mmap; vma && !err; vma = vma->vm_next) { if (vma->vm_ops && vma->vm_ops->migrate) { err = vma->vm_ops->migrate(vma, to, from, flags); if (err) @@ -1092,3 +1149,4 @@ int migrate_vmas(struct mm_struct *mm, const nodemask_t *to, } return err; } +#endif