RFC: better block swap batching and a different take on swap_ops

[Christoph Hellwig <hch@lst.de>]

Hi all,

this series makes use of the swap_iocb for block as well so that it
doesn't do inefficient single-bio I/O, and then rebases the swap_ops
from Baoquan on top of the now very different method structure.

This is very hot off the press and has only survived very basic testing.

Diffstat:
 Documentation/filesystems/locking.rst     |    5 
 Documentation/filesystems/vfs.rst         |    4 
 drivers/gpu/drm/i915/gem/i915_gem_shmem.c |    2 
 drivers/gpu/drm/ttm/ttm_backup.c          |    2 
 fs/nfs/file.c                             |    4 
 fs/smb/client/file.c                      |    4 
 include/linux/shmem_fs.h                  |    5 
 include/linux/swap.h                      |    7 
 mm/madvise.c                              |   16 
 mm/page_io.c                              |  544 ++++++++++++++----------------
 mm/shmem.c                                |   18 
 mm/swap.h                                 |   52 +-
 mm/swap_state.c                           |   40 +-
 mm/swapfile.c                             |   11 
 mm/vmscan.c                               |   88 ++--
 15 files changed, 402 insertions(+), 400 deletions(-)