Chagnes in V2:
 - as suggested by Paolo, add support to track if root_group have any
 pending requests, and use that to handle the situation when only one
 group is activated while root group doesn't have any pending requests.
 - modify commit message in patch 2

Yu Kuai (4):
  block, bfq: add support to track if root_group have any pending
    requests
  block, bfq: do not idle if only one cgroup is activated
  block, bfq: add support to record request size information
  block, bfq: consider request size in bfq_asymmetric_scenario()

 block/bfq-iosched.c | 69 ++++++++++++++++++++++++++++++++++++++-------
 block/bfq-iosched.h | 29 +++++++++++++++++--
 block/bfq-wf2q.c    | 37 +++++++++++++++---------
 3 files changed, 110 insertions(+), 25 deletions(-)

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2.31.1