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| author | Tejun Heo <tj@kernel.org> | 2020-09-01 21:52:51 +0300 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2020-09-02 04:38:32 +0300 |
| commit | c421a3eb2e27402c14131a14390551ae6cdb15fa (patch) | |
| tree | c74b6cfe35d605e68085c2b04c72a4e8202c9a29 /block/blk-cgroup.c | |
| parent | b0853ab4a238c54b8f97ca7dde1ae156e2bbd5e4 (diff) | |
| download | linux-c421a3eb2e27402c14131a14390551ae6cdb15fa.tar.xz | |
blk-iocost: revamp debt handling
Debt handling had several issues.
* How much inuse a debtor carries wasn't clearly defined. inuse would be
driven down over time from not issuing IOs but it'd be better to clamp it
to minimum immediately once in debt.
* How much can be paid off was determined by hweight_inuse. As inuse was
driven down, the payment amount would fall together regardless of the
debtor's active weight. This means that the debtors were punished harshly.
* ioc_rqos_merge() wasn't calling blkcg_schedule_throttle() after
iocg_kick_delay().
This patch revamps debt handling so that
* Debt handling owns inuse for iocgs in debt and keeps them at zero.
* Payment amount is determined by hweight_active. This is more deterministic
and safer than hweight_inuse but still far from ideal in that it doesn't
factor in possible donations from other iocgs for debt payments. This
likely needs further improvements in the future.
* iocg_rqos_merge() now calls blkcg_schedule_throttle() as necessary.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Andy Newell <newella@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block/blk-cgroup.c')
0 files changed, 0 insertions, 0 deletions