[v2,0/5] Make PageWriteback use the PageLocked optimisation

Message

Matthew Wilcox April 16, 2020, 3:46 p.m. UTC

From: "Matthew Wilcox (Oracle)" <[e-mail]>

PageWaiters is used by PageWriteback and PageLocked (and no other page
flags), so it makes sense to use the same codepaths that have already been
optimised for PageLocked, even if there's probably no real performance
benefit to be had.

v2: Rebased to 5.7-rc1
 - Split up patches better
 - Moved the BUG() from end_page_writeback() to __clear_page_writeback()
   as requested by Jan Kara.
 - Converted the BUG() to WARN_ON()
 - Removed TestClearPageWriteback

Matthew Wilcox (Oracle) (5):
  mm: Remove definition of clear_bit_unlock_is_negative_byte
  mm: Move PG_writeback into the bottom byte
  mm: Convert writeback BUG to WARN_ON
  mm: Use clear_bit_unlock_is_negative_byte for PageWriteback
  mm: Remove TestClearPageWriteback

 include/linux/page-flags.h |  8 ++++----
 mm/filemap.c               | 41 +++++--------------------------------
 mm/page-writeback.c        | 42 +++++++++++++++++++++++---------------
 3 files changed, 34 insertions(+), 57 deletions(-)