Changes from v1[1] * Dropped 0002-block-add-request-io_data_len.patch and updated to use rq->stats_sectors instead as suggested by Pavel Begunkov. This patchset improves the following two iocost control behaviors. * iocost was failing to punish heavy shared IO generators (file metadata, memory reclaim) through use_delay mechanism - use_delay automatically decays which works well for iolatency but doesn't match how iocost behaves. This led to e.g. memory bombs which generate a lot of swap IOs to use over their allotted amount. This is fixed by adding non-decaying use_delay mechanism. * The same latency targets were being applied regardless of the IO sizes. While this works fine for loose targets, it gets in the way when trying to tigthen them - a latency target adequate for a 4k IO is too short for a 1 meg IO. iocost now discounts the size portion of cost when testing whether a given IO met or missed its latency target. While at it, it also makes minor changse to iocost_monitor.py. This patchset contains the following five patches. 0001-blk-iocost-switch-to-fixed-non-auto-decaying-use_del.patch 0002-blk-iocost-account-for-IO-size-when-testing-latencie.patch 0003-iocost_monitor-exit-successfully-if-interval-is-zero.patch 0004-iocost_monitor-drop-string-wrap-around-numbers-when-.patch and is also available in the following git branch. git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup.git iocost-delay-latency-v2 diffstat follows. Thanks. block/Kconfig | 1 block/blk-cgroup.c | 6 ++++ block/blk-iocost.c | 56 +++++++++++++++++++++++++++++------------ include/linux/blk-cgroup.h | 43 ++++++++++++++++++++++++------- tools/cgroup/iocost_monitor.py | 48 +++++++++++++++++++---------------- 5 files changed, 106 insertions(+), 48 deletions(-) -- tejun [1] http://lkml.kernel.org/r/20200408201450.3959560-1-tj@xxxxxxxxxx
