From: Matthew Wilcox <mawilcox@xxxxxxxxxxxxx> 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mapping is terse, and out of date (it does not mention the possibility of PAGE_MAPPING_MOVABLE).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@xxxxxxxxxxxxx Signed-off-by: Matthew Wilcox <mawilcox@xxxxxxxxxxxxx> Acked-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx> Acked-by: Michal Hocko <mhocko@xxxxxxxx> Acked-by: Christoph Lameter <cl@xxxxxxxxx> Cc: Randy Dunlap <rdunlap@xxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- include/linux/mm_types.h | 12 +++--------- 1 file changed, 3 insertions(+), 9 deletions(-) diff -puN include/linux/mm_types.h~mm-improve-comment-on-page-mapping include/linux/mm_types.h --- a/include/linux/mm_types.h~mm-improve-comment-on-page-mapping +++ a/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 */ _ -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
