[PATCH v1 0/6] Remove rw_page

[Minchan Kim]

Recently, there was a dicussion about removing rw_page due to maintainance
burden[1] but the problem was zram because zram has a clear win for the
benchmark at that time. The reason why only zram have a win is due to
bio allocation wait time from mempool under extreme memory pressure.

Christoph Hellwig suggested we can use on-stack-bio for rw_page devices.
This patch implements it and replace rw_page operations with on-stack-bio
and then finally, remove rw_page interface completely.

This patch is based on linux-next-20170804

[1] http://lkml.kernel.org/r/<20170728165604.10455-1-ross.zwisler@xxxxxxxxxxxxxxx>

Minchan Kim (6):
  bdi: introduce BDI_CAP_SYNC
  fs: use on-stack-bio if backing device has BDI_CAP_SYNC capability
  mm:swap: remove end_swap_bio_write argument
  mm:swap: use on-stack-bio for BDI_CAP_SYNC devices
  zram: remove zram_rw_page
  fs: remove rw_page

 drivers/block/brd.c           |   2 +
 drivers/block/zram/zram_drv.c |  54 +---------------
 drivers/nvdimm/btt.c          |   2 +
 drivers/nvdimm/pmem.c         |   2 +
 fs/block_dev.c                |  76 ----------------------
 fs/mpage.c                    |  45 +++++++++++--
 include/linux/backing-dev.h   |   7 ++
 include/linux/blkdev.h        |   4 --
 include/linux/swap.h          |   6 +-
 mm/page_io.c                  | 145 +++++++++++++++++++++++++-----------------
 mm/swapfile.c                 |   3 +
 mm/zswap.c                    |   2 +-
 12 files changed, 147 insertions(+), 201 deletions(-)

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2.7.4