[PATCH v6 0/2] mm, netfs, fscache: Stop read optimisation when folio removed from pagecache

[David Howells <dhowells@redhat.com>]

Hi Willy,

Is this okay by you?  You said you wanted to look at the remaining uses of
page_has_private(), of which there are then three after these patches, not
counting folio_has_private():

	arch/s390/kernel/uv.c:          if (page_has_private(page))
	mm/khugepaged.c:                    1 + page_mapcount(page) + page_has_private(page)) {
	mm/migrate_device.c:            extra += 1 + page_has_private(page);

--
I've split the folio_has_private()/filemap_release_folio() call pair
merging into its own patch, separate from the actual bugfix and pulled out
the folio_needs_release() function into mm/internal.h and made
filemap_release_folio() use it.  I've also got rid of the bit clearances
from the network filesystem evict_inode functions as they doesn't seem to
be necessary.

Note that the last vestiges of try_to_release_page() got swept away, so I
rebased and dealt with that.  One comment remained, which is removed by the
first patch.

David

Changes:
========
ver #6)
 - Drop the third patch which removes a duplicate check in vmscan().

ver #5)
 - Rebased on linus/master.  try_to_release_page() has now been entirely
   replaced by filemap_release_folio(), barring one comment.
 - Cleaned up some pairs in ext4.

ver #4)
 - Split has_private/release call pairs into own patch.
 - Moved folio_needs_release() to mm/internal.h and removed open-coded
   version from filemap_release_folio().
 - Don't need to clear AS_RELEASE_ALWAYS in ->evict_inode().
 - Added experimental patch to reduce shrink_folio_list().

ver #3)
 - Fixed mapping_clear_release_always() to use clear_bit() not set_bit().
 - Moved a '&&' to the correct line.

ver #2)
 - Rewrote entirely according to Willy's suggestion[1].

Link: https://lore.kernel.org/r/Yk9V/03wgdYi65Lb@casper.infradead.org/ [1]
Link: https://lore.kernel.org/r/164928630577.457102.8519251179327601178.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/166844174069.1124521.10890506360974169994.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/166869495238.3720468.4878151409085146764.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/1459152.1669208550@warthog.procyon.org.uk/ # v3 also
Link: https://lore.kernel.org/r/166924370539.1772793.13730698360771821317.stgit@warthog.procyon.org.uk/ # v4
Link: https://lore.kernel.org/r/167172131368.2334525.8569808925687731937.stgit@warthog.procyon.org.uk/ # v5
---
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David Howells (2):
  mm: Merge folio_has_private()/filemap_release_folio() call pairs
  mm, netfs, fscache: Stop read optimisation when folio removed from
    pagecache

 fs/9p/cache.c           |  2 ++
 fs/afs/internal.h       |  2 ++
 fs/cachefiles/namei.c   |  2 ++
 fs/ceph/cache.c         |  2 ++
 fs/cifs/fscache.c       |  2 ++
 fs/ext4/move_extent.c   | 12 ++++--------
 fs/splice.c             |  3 +--
 include/linux/pagemap.h | 16 ++++++++++++++++
 mm/filemap.c            |  2 ++
 mm/huge_memory.c        |  3 +--
 mm/internal.h           | 11 +++++++++++
 mm/khugepaged.c         |  3 +--
 mm/memory-failure.c     |  8 +++-----
 mm/migrate.c            |  3 +--
 mm/truncate.c           |  6 ++----
 mm/vmscan.c             |  8 ++++----
 16 files changed, 56 insertions(+), 29 deletions(-)