diff options
Diffstat (limited to 'mm/migrate.c')
| -rw-r--r-- | mm/migrate.c | 58 |
1 files changed, 38 insertions, 20 deletions
diff --git a/mm/migrate.c b/mm/migrate.c index 352de555626..34132f8e910 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -375,7 +375,7 @@ void migrate_page_copy(struct page *newpage, struct page *page) * redo the accounting that clear_page_dirty_for_io undid, * but we can't use set_page_dirty because that function * is actually a signal that all of the page has become dirty. - * Wheras only part of our page may be dirty. + * Whereas only part of our page may be dirty. */ __set_page_dirty_nobuffers(newpage); } @@ -564,7 +564,7 @@ static int fallback_migrate_page(struct address_space *mapping, * == 0 - success */ static int move_to_new_page(struct page *newpage, struct page *page, - int remap_swapcache) + int remap_swapcache, bool sync) { struct address_space *mapping; int rc; @@ -586,18 +586,28 @@ static int move_to_new_page(struct page *newpage, struct page *page, mapping = page_mapping(page); if (!mapping) rc = migrate_page(mapping, newpage, page); - else if (mapping->a_ops->migratepage) + else { /* - * Most pages have a mapping and most filesystems - * should provide a migration function. Anonymous - * pages are part of swap space which also has its - * own migration function. This is the most common - * path for page migration. + * Do not writeback pages if !sync and migratepage is + * not pointing to migrate_page() which is nonblocking + * (swapcache/tmpfs uses migratepage = migrate_page). */ - rc = mapping->a_ops->migratepage(mapping, - newpage, page); - else - rc = fallback_migrate_page(mapping, newpage, page); + if (PageDirty(page) && !sync && + mapping->a_ops->migratepage != migrate_page) + rc = -EBUSY; + else if (mapping->a_ops->migratepage) + /* + * Most pages have a mapping and most filesystems + * should provide a migration function. Anonymous + * pages are part of swap space which also has its + * own migration function. This is the most common + * path for page migration. + */ + rc = mapping->a_ops->migratepage(mapping, + newpage, page); + else + rc = fallback_migrate_page(mapping, newpage, page); + } if (rc) { newpage->mapping = NULL; @@ -623,7 +633,7 @@ static int unmap_and_move(new_page_t get_new_page, unsigned long private, struct page *newpage = get_new_page(page, private, &result); int remap_swapcache = 1; int charge = 0; - struct mem_cgroup *mem = NULL; + struct mem_cgroup *mem; struct anon_vma *anon_vma = NULL; if (!newpage) @@ -641,7 +651,7 @@ static int unmap_and_move(new_page_t get_new_page, unsigned long private, rc = -EAGAIN; if (!trylock_page(page)) { - if (!force) + if (!force || !sync) goto move_newpage; /* @@ -678,7 +688,7 @@ static int unmap_and_move(new_page_t get_new_page, unsigned long private, } /* charge against new page */ - charge = mem_cgroup_prepare_migration(page, newpage, &mem); + charge = mem_cgroup_prepare_migration(page, newpage, &mem, GFP_KERNEL); if (charge == -ENOMEM) { rc = -ENOMEM; goto unlock; @@ -686,7 +696,15 @@ static int unmap_and_move(new_page_t get_new_page, unsigned long private, BUG_ON(charge); if (PageWriteback(page)) { - if (!force || !sync) + /* + * For !sync, there is no point retrying as the retry loop + * is expected to be too short for PageWriteback to be cleared + */ + if (!sync) { + rc = -EBUSY; + goto uncharge; + } + if (!force) goto uncharge; wait_on_page_writeback(page); } @@ -757,14 +775,14 @@ static int unmap_and_move(new_page_t get_new_page, unsigned long private, skip_unmap: if (!page_mapped(page)) - rc = move_to_new_page(newpage, page, remap_swapcache); + rc = move_to_new_page(newpage, page, remap_swapcache, sync); if (rc && remap_swapcache) remove_migration_ptes(page, page); /* Drop an anon_vma reference if we took one */ if (anon_vma) - drop_anon_vma(anon_vma); + put_anon_vma(anon_vma); uncharge: if (!charge) @@ -850,13 +868,13 @@ static int unmap_and_move_huge_page(new_page_t get_new_page, try_to_unmap(hpage, TTU_MIGRATION|TTU_IGNORE_MLOCK|TTU_IGNORE_ACCESS); if (!page_mapped(hpage)) - rc = move_to_new_page(new_hpage, hpage, 1); + rc = move_to_new_page(new_hpage, hpage, 1, sync); if (rc) remove_migration_ptes(hpage, hpage); if (anon_vma) - drop_anon_vma(anon_vma); + put_anon_vma(anon_vma); out: unlock_page(hpage); |