[PATCH BUGFIX/IMPROVEMENT 0/4] bfq: two fixes and one improvement related to I/O control

From: Paolo Valente
Date: Thu Aug 16 2018 - 12:52:27 EST

Hi Jens,

while working a little bit on cgroups I/O control, I found two nasty
bugs in bfq. They break bandwidth control in simple configurations
with one-process groups. These bugs are fixed by the first two patches
in this series.

These fixes improved I/O control so much, that I could reduce the
write overcharge factor, used by bfq to counter write-induced
issues. This reduction is performed by the third patch.

The fourth patch contains a little code improvement I made in a
function that has to do with I/O control.

I hope we are still in time for 4.19.


Paolo Valente (4):
block, bfq: readd missing reset of parent-entity service
block, bfq: always update the budget of an entity when needed
block, bfq: reduce write overcharge
block, bfq: improve code of bfq_bfqq_charge_time

block/bfq-iosched.c | 54 +++++++++++++++++++++++++++++++++++++++--------------
block/bfq-wf2q.c | 22 +++++++++++-----------
2 files changed, 51 insertions(+), 25 deletions(-)