diff options
Diffstat (limited to 'mm/migrate.c')
| -rw-r--r-- | mm/migrate.c | 37 |
1 files changed, 23 insertions, 14 deletions
diff --git a/mm/migrate.c b/mm/migrate.c index a16b15090df3..ac6f4939bb59 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -100,7 +100,7 @@ int isolate_movable_page(struct page *page, isolate_mode_t mode) /* * Check PageMovable before holding a PG_lock because page's owner * assumes anybody doesn't touch PG_lock of newly allocated page - * so unconditionally grapping the lock ruins page's owner side. + * so unconditionally grabbing the lock ruins page's owner side. */ if (unlikely(!__PageMovable(page))) goto out_putpage; @@ -374,7 +374,7 @@ unlock: } #endif -static int expected_page_refs(struct page *page) +static int expected_page_refs(struct address_space *mapping, struct page *page) { int expected_count = 1; @@ -384,7 +384,7 @@ static int expected_page_refs(struct page *page) */ expected_count += is_device_private_page(page); expected_count += is_device_public_page(page); - if (page_mapping(page)) + if (mapping) expected_count += hpage_nr_pages(page) + page_has_private(page); return expected_count; @@ -405,7 +405,7 @@ int migrate_page_move_mapping(struct address_space *mapping, XA_STATE(xas, &mapping->i_pages, page_index(page)); struct zone *oldzone, *newzone; int dirty; - int expected_count = expected_page_refs(page) + extra_count; + int expected_count = expected_page_refs(mapping, page) + extra_count; if (!mapping) { /* Anonymous page without mapping */ @@ -709,7 +709,6 @@ static bool buffer_migrate_lock_buffers(struct buffer_head *head, /* Simple case, sync compaction */ if (mode != MIGRATE_ASYNC) { do { - get_bh(bh); lock_buffer(bh); bh = bh->b_this_page; @@ -720,18 +719,15 @@ static bool buffer_migrate_lock_buffers(struct buffer_head *head, /* async case, we cannot block on lock_buffer so use trylock_buffer */ do { - get_bh(bh); if (!trylock_buffer(bh)) { /* * We failed to lock the buffer and cannot stall in * async migration. Release the taken locks */ struct buffer_head *failed_bh = bh; - put_bh(failed_bh); bh = head; while (bh != failed_bh) { unlock_buffer(bh); - put_bh(bh); bh = bh->b_this_page; } return false; @@ -754,7 +750,7 @@ static int __buffer_migrate_page(struct address_space *mapping, return migrate_page(mapping, newpage, page, mode); /* Check whether page does not have extra refs before we do more work */ - expected_count = expected_page_refs(page); + expected_count = expected_page_refs(mapping, page); if (page_count(page) != expected_count) return -EAGAIN; @@ -818,7 +814,6 @@ unlock_buffers: bh = head; do { unlock_buffer(bh); - put_bh(bh); bh = bh->b_this_page; } while (bh != head); @@ -916,7 +911,7 @@ static int fallback_migrate_page(struct address_space *mapping, */ if (page_has_private(page) && !try_to_release_page(page, GFP_KERNEL)) - return -EAGAIN; + return mode == MIGRATE_SYNC ? -EAGAIN : -EBUSY; return migrate_page(mapping, newpage, page, mode); } @@ -1135,10 +1130,13 @@ out: * If migration is successful, decrease refcount of the newpage * which will not free the page because new page owner increased * refcounter. As well, if it is LRU page, add the page to LRU - * list in here. + * list in here. Use the old state of the isolated source page to + * determine if we migrated a LRU page. newpage was already unlocked + * and possibly modified by its owner - don't rely on the page + * state. */ if (rc == MIGRATEPAGE_SUCCESS) { - if (unlikely(__PageMovable(newpage))) + if (unlikely(!is_lru)) put_page(newpage); else putback_lru_page(newpage); @@ -1289,7 +1287,7 @@ static int unmap_and_move_huge_page(new_page_t get_new_page, struct anon_vma *anon_vma = NULL; /* - * Movability of hugepages depends on architectures and hugepage size. + * Migratability of hugepages depends on architectures and their size. * This check is necessary because some callers of hugepage migration * like soft offline and memory hotremove don't walk through page * tables or check whether the hugepage is pmd-based or not before @@ -1317,6 +1315,16 @@ static int unmap_and_move_huge_page(new_page_t get_new_page, lock_page(hpage); } + /* + * Check for pages which are in the process of being freed. Without + * page_mapping() set, hugetlbfs specific move page routine will not + * be called and we could leak usage counts for subpools. + */ + if (page_private(hpage) && !page_mapping(hpage)) { + rc = -EBUSY; + goto out_unlock; + } + if (PageAnon(hpage)) anon_vma = page_get_anon_vma(hpage); @@ -1347,6 +1355,7 @@ put_anon: put_new_page = NULL; } +out_unlock: unlock_page(hpage); out: if (rc != -EAGAIN) |