bdi: introduce BDI_CAP_SYNCHRONOUS_IO
authorMinchan Kim <minchan@kernel.org>
Thu, 16 Nov 2017 01:33:00 +0000 (17:33 -0800)
committerLinus Torvalds <torvalds@linux-foundation.org>
Thu, 16 Nov 2017 02:21:02 +0000 (18:21 -0800)
commit23c47d2ada9f96731492a67b28c0072715075baa
treedbe8a9322eab448997e27b19b1b39b235eaddd2a
parente447a0151f7ce8dd884fea48279274bd64434c29
bdi: introduce BDI_CAP_SYNCHRONOUS_IO

As discussed at

  https://lkml.kernel.org/r/<20170728165604.10455-1-ross.zwisler@linux.intel.com>

someday we will remove rw_page().  If so, we need something to detect
such super-fast storage on which synchronous IO operations like the
current rw_page are always a win.

Introduces BDI_CAP_SYNCHRONOUS_IO to indicate such devices.  With it, we
could use various optimization techniques.

Link: http://lkml.kernel.org/r/1505886205-9671-3-git-send-email-minchan@kernel.org
Signed-off-by: Minchan Kim <minchan@kernel.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ilya Dryomov <idryomov@gmail.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Huang Ying <ying.huang@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
drivers/block/brd.c
drivers/block/zram/zram_drv.c
drivers/nvdimm/btt.c
drivers/nvdimm/pmem.c
include/linux/backing-dev.h