page-flags: define behavior of FS/IO-related flags on compound pages
authorKirill A. Shutemov <>
Sat, 16 Jan 2016 00:51:28 +0000 (16:51 -0800)
committerLinus Torvalds <>
Sat, 16 Jan 2016 01:56:32 +0000 (17:56 -0800)
page-flags: define behavior of FS/IO-related flags on compound pages

It seems we don't have compound page on FS/IO path currently.  Use
PF_NO_COMPOUND to catch if we have.

The odd exception is PG_dirty: sound uses compound pages and maps them
with PTEs.  PF_NO_COMPOUND triggers VM_BUG_ON() in set_page_dirty() on
handling shared fault.  Let's use PF_HEAD for PG_dirty.

Signed-off-by: Kirill A. Shutemov <>
Cc: Andrea Arcangeli <>
Cc: Hugh Dickins <>
Cc: Dave Hansen <>
Cc: Mel Gorman <>
Cc: Rik van Riel <>
Cc: Vlastimil Babka <>
Cc: Christoph Lameter <>
Cc: Naoya Horiguchi <>
Cc: Steve Capper <>
Cc: "Aneesh Kumar K.V" <>
Cc: Johannes Weiner <>
Cc: Michal Hocko <>
Cc: Jerome Marchand <>
Cc: Jérôme Glisse <>
Signed-off-by: Andrew Morton <>
Signed-off-by: Linus Torvalds <>