From: Matthew Wilcox Date: Thu, 1 Feb 2018 00:18:55 +0000 (-0800) Subject: mm: improve comment on page->mapping X-Git-Tag: for-linus-20180210~30^2~40 X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=b26435a0115b245ea2dd705efcce877ec417bc74;p=linux-block.git 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mapping is terse, and out of date (it does not mention the possibility of PAGE_MAPPING_MOVABLE).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 --- 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 */