mm: rearrange page flags

Move PG_writeback into bottom byte so that it can use PG_waiters in a
later patch.  Move PG_head into bottom byte as well to match with where
'order' is moving next.  PG_active and PG_workingset move into the second
byte to make room for them.

By putting PG_head in bit 6, we ensure that it is cleared by assigning the
folio order to the bottom byte of the first tail page (since the order
cannot be larger than 63).

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Matthew Wilcox (Oracle) <[email protected]>
Cc: David Hildenbrand <[email protected]>
Cc: Jens Axboe <[email protected]>
Cc: Sidhartha Kumar <[email protected]>
Cc: Yanteng Si <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

0 files changed, 0 insertions, 0 deletions