diff options
| -rw-r--r-- | mm/balloon_compaction.c | 10 | ||||
| -rw-r--r-- | mm/migrate.c | 46 |
2 files changed, 28 insertions, 28 deletions
diff --git a/mm/balloon_compaction.c b/mm/balloon_compaction.c index fcad8322ef36..d3116be5a00f 100644 --- a/mm/balloon_compaction.c +++ b/mm/balloon_compaction.c @@ -199,23 +199,17 @@ int balloon_page_migrate(struct page *newpage, struct balloon_dev_info *balloon = balloon_page_device(page); int rc = -EAGAIN; - /* - * Block others from accessing the 'newpage' when we get around to - * establishing additional references. We should be the only one - * holding a reference to the 'newpage' at this point. - */ - BUG_ON(!trylock_page(newpage)); + VM_BUG_ON_PAGE(!PageLocked(page), page); + VM_BUG_ON_PAGE(!PageLocked(newpage), newpage); if (WARN_ON(!__is_movable_balloon_page(page))) { dump_page(page, "not movable balloon page"); - unlock_page(newpage); return rc; } if (balloon && balloon->migratepage) rc = balloon->migratepage(balloon, newpage, page, mode); - unlock_page(newpage); return rc; } #endif /* CONFIG_BALLOON_COMPACTION */ diff --git a/mm/migrate.c b/mm/migrate.c index 2f2e2236daf7..6d7774ef0e6c 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -727,13 +727,8 @@ static int move_to_new_page(struct page *newpage, struct page *page, struct address_space *mapping; int rc; - /* - * Block others from accessing the page when we get around to - * establishing additional references. We are the only one - * holding a reference to the new page at this point. - */ - if (!trylock_page(newpage)) - BUG(); + VM_BUG_ON_PAGE(!PageLocked(page), page); + VM_BUG_ON_PAGE(!PageLocked(newpage), newpage); /* Prepare mapping for the new page.*/ newpage->index = page->index; @@ -774,9 +769,6 @@ static int move_to_new_page(struct page *newpage, struct page *page, remove_migration_ptes(page, newpage); page->mapping = NULL; } - - unlock_page(newpage); - return rc; } @@ -861,6 +853,17 @@ static int __unmap_and_move(struct page *page, struct page *newpage, } } + /* + * Block others from accessing the new page when we get around to + * establishing additional references. We are usually the only one + * holding a reference to newpage at this point. We used to have a BUG + * here if trylock_page(newpage) fails, but would like to allow for + * cases where there might be a race with the previous use of newpage. + * This is much like races on refcount of oldpage: just don't BUG(). + */ + if (unlikely(!trylock_page(newpage))) + goto out_unlock; + if (unlikely(isolated_balloon_page(page))) { /* * A ballooned page does not need any special attention from @@ -870,7 +873,7 @@ static int __unmap_and_move(struct page *page, struct page *newpage, * the page migration right away (proteced by page lock). */ rc = balloon_page_migrate(newpage, page, mode); - goto out_unlock; + goto out_unlock_both; } /* @@ -889,30 +892,27 @@ static int __unmap_and_move(struct page *page, struct page *newpage, VM_BUG_ON_PAGE(PageAnon(page), page); if (page_has_private(page)) { try_to_free_buffers(page); - goto out_unlock; + goto out_unlock_both; } - goto skip_unmap; - } - - /* Establish migration ptes or remove ptes */ - if (page_mapped(page)) { + } else if (page_mapped(page)) { + /* Establish migration ptes */ try_to_unmap(page, TTU_MIGRATION|TTU_IGNORE_MLOCK|TTU_IGNORE_ACCESS); page_was_mapped = 1; } -skip_unmap: if (!page_mapped(page)) rc = move_to_new_page(newpage, page, page_was_mapped, mode); if (rc && page_was_mapped) remove_migration_ptes(page, page); +out_unlock_both: + unlock_page(newpage); +out_unlock: /* Drop an anon_vma reference if we took one */ if (anon_vma) put_anon_vma(anon_vma); - -out_unlock: unlock_page(page); out: return rc; @@ -1056,6 +1056,9 @@ static int unmap_and_move_huge_page(new_page_t get_new_page, if (PageAnon(hpage)) anon_vma = page_get_anon_vma(hpage); + if (unlikely(!trylock_page(new_hpage))) + goto put_anon; + if (page_mapped(hpage)) { try_to_unmap(hpage, TTU_MIGRATION|TTU_IGNORE_MLOCK|TTU_IGNORE_ACCESS); @@ -1068,6 +1071,9 @@ static int unmap_and_move_huge_page(new_page_t get_new_page, if (rc != MIGRATEPAGE_SUCCESS && page_was_mapped) remove_migration_ptes(hpage, hpage); + unlock_page(new_hpage); + +put_anon: if (anon_vma) put_anon_vma(anon_vma); |