From b26435a0115b245ea2dd705efcce877ec417bc74 Mon Sep 17 00:00:00 2001 From: Matthew Wilcox Date: Wed, 31 Jan 2018 16:18:55 -0800 Subject: mm: improve comment on page->mapping The comment on page->mapping is terse, and out of date (it does not mention the possibility of PAGE_MAPPING_MOVABLE). Instead, point the interested reader to page-flags.h where there is a much better comment. Link: http://lkml.kernel.org/r/20171220155552.15884-5-willy@infradead.org Signed-off-by: Matthew Wilcox Acked-by: Kirill A. Shutemov Acked-by: Michal Hocko Acked-by: Christoph Lameter Cc: Randy Dunlap Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/mm_types.h | 12 +++--------- 1 file changed, 3 insertions(+), 9 deletions(-) (limited to 'include/linux/mm_types.h') diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index c2294e6204e8..8c3b8cea22ee 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -50,15 +50,9 @@ struct page { unsigned long flags; /* Atomic flags, some possibly * updated asynchronously */ union { - struct address_space *mapping; /* If low bit clear, points to - * inode address_space, or NULL. - * If page mapped as anonymous - * memory, low bit is set, and - * it points to anon_vma object - * or KSM private structure. See - * PAGE_MAPPING_ANON and - * PAGE_MAPPING_KSM. - */ + /* See page-flags.h for the definition of PAGE_MAPPING_FLAGS */ + struct address_space *mapping; + void *s_mem; /* slab first object */ atomic_t compound_mapcount; /* first tail page */ /* page_deferred_list().next -- second tail page */ -- cgit v1.2.3-59-g8ed1b