[PATCH 0/1 RFC] read_policy type heuristic

[Anand Jain <anand.jain@oracle.com>]

POC patch proposes a read_policy type Heuristic to solve the problem of
poor read performance for the mirrored stripes on mixed device types.
Read_policy Heuristic has benefits of both pid and has no dependency on
block layer iostats. Instead, it uses statically defined device_type and
its latency.

This patch is a POC patch that has no performance analysis yet. I am
sending this to get some early feedback.

For the read_policy type Latency, please refer here [1]. The read_policy
type Latency works better overall, and it is self-tuning based on the IO.

[1]
https://lore.kernel.org/linux-btrfs/20210120123437.OVx7ybGaVfmOdZxtpp43qcB_ORHQQs5OzPSzr3ZUGbo@z/T/#u

Anand Jain (1):
  btrfs: add read_policy heuristic

 fs/btrfs/sysfs.c   |  2 +-
 fs/btrfs/volumes.c | 52 ++++++++++++++++++++++++++++++++++++++++++++++
 fs/btrfs/volumes.h |  2 ++
 3 files changed, 55 insertions(+), 1 deletion(-)

-- 
2.33.1