[PATCH v2 0/3] Implement BFQ per-device weight interface

[Fam Zheng]

(Revision starting from v2 since v1 was used off-list)

Hi Paolo and others,

This adds to BFQ the missing per-device weight interfaces:
blkio.bfq.weight_device on legacy and io.bfq.weight on unified. The
implementation pretty closely resembles what we had in CFQ and the parsing code
is basically reused.

Tests
=====

Using two cgroups and three block devices, having weights setup as:

Cgroup          test1           test2
============================================
default         100             500
sda             500             100
sdb             default         default
sdc             200             200

cgroup v1 runs
--------------

    sda.test1.out:   READ: bw=913MiB/s
    sda.test2.out:   READ: bw=183MiB/s

    sdb.test1.out:   READ: bw=213MiB/s
    sdb.test2.out:   READ: bw=1054MiB/s

    sdc.test1.out:   READ: bw=650MiB/s
    sdc.test2.out:   READ: bw=650MiB/s

cgroup v2 runs
--------------

    sda.test1.out:   READ: bw=915MiB/s
    sda.test2.out:   READ: bw=184MiB/s

    sdb.test1.out:   READ: bw=216MiB/s
    sdb.test2.out:   READ: bw=1069MiB/s

    sdc.test1.out:   READ: bw=621MiB/s
    sdc.test2.out:   READ: bw=622MiB/s

Fam Zheng (3):
  bfq: Fix the missing barrier in __bfq_entity_update_weight_prio
  bfq: Extract bfq_group_set_weight from bfq_io_set_weight_legacy
  bfq: Add per-device weight

 block/bfq-cgroup.c  | 151 +++++++++++++++++++++++++++++++++++++++-------------
 block/bfq-iosched.h |   3 ++
 block/bfq-wf2q.c    |   2 +
 3 files changed, 119 insertions(+), 37 deletions(-)

-- 
2.11.0