linux-kernel - [PATCHSET for-5.10/block] iocost: improve debt forgiveness logic

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Date:   Thu, 17 Sep 2020 20:44:51 -0400
From:   Tejun Heo <tj@...nel.org>
To:     axboe@...nel.dk
Cc:     linux-block@...r.kernel.org, cgroups@...r.kernel.org,
        kernel-team@...com, linux-kernel@...r.kernel.org
Subject: [PATCHSET for-5.10/block] iocost: improve debt forgiveness logic

Hello,

Debt reduction logic was recently added by dda1315f1853 ("blk-iocost: halve
debts if device stays idle"). While it was effective at avoiding
pathological cases where some iocgs were kept delayed while the device was
most idle, it wasn't very effective at addressing more complex conditions
and could leave low priority cgroups unnecessarily harshly throttled under
moderate load.

This patchset improves the debt forgiveness logic so that it's more
effective at reducing such unnecessary throttling. This patchset contains
the following five patches:

 0001-iocost-factor-out-ioc_forgive_debts.patch
 0002-iocost-replace-nr_shortages-cond-in-ioc_forgive_debt.patch
 0003-iocost-recalculate-delay-after-debt-reduction.patch
 0004-iocost-reimplement-debt-forgiveness-using-average-us.patch
 0005-iocost-add-iocg_forgive_debt-tracepoint.patch

and is also available in the following git tree:

 git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup.git iocost-debt-forgiveness

diffstat follows. Thanks.

 block/blk-iocost.c            |  141 +++++++++++++++++++++++++++++-------------
 include/trace/events/iocost.h |   41 ++++++++++++
 2 files changed, 141 insertions(+), 41 deletions(-)

--
tejun