korg/linux
0
0
Fork 0
mirror of https://mirrors.bfsu.edu.cn/git/linux.git synced 2024-09-21 20:22:13 +08:00
Code Issues Packages Projects Releases Wiki Activity
915,816 Commits 111 Branches 5,157 Tags 4.7 GiB
C 97.6%
Assembly 1%
Shell 0.5%
Python 0.3%
Makefile 0.3%
81ca627a93
Go to file
Tejun Heo 81ca627a93 iocost: don't let vrate run wild while there's no saturation signal 
When the QoS targets are met and nothing is being throttled, there's
no way to tell how saturated the underlying device is - it could be
almost entirely idle, at the cusp of saturation or anywhere inbetween.
Given that there's no information, it's best to keep vrate as-is in
this state.  Before 7cd806a9a9 ("iocost: improve nr_lagging
handling"), this was the case - if the device isn't missing QoS
targets and nothing is being throttled, busy_level was reset to zero.

While fixing nr_lagging handling, 7cd806a9a9 ("iocost: improve
nr_lagging handling") broke this.  Now, while the device is hitting
QoS targets and nothing is being throttled, vrate keeps getting
adjusted according to the existing busy_level.

This led to vrate keeping climing till it hits max when there's an IO
issuer with limited request concurrency if the vrate started low.
vrate starts getting adjusted upwards until the issuer can issue IOs
w/o being throttled.  From then on, QoS targets keeps getting met and
nothing on the system needs throttling and vrate keeps getting
increased due to the existing busy_level.

This patch makes the following changes to the busy_level logic.

* Reset busy_level if nr_shortages is zero to avoid the above
  scenario.

* Make non-zero nr_lagging block lowering nr_level but still clear
  positive busy_level if there's clear non-saturation signal - QoS
  targets are met and nr_shortages is non-zero.  nr_lagging's role is
  preventing adjusting vrate upwards while there are long-running
  commands and it shouldn't keep busy_level positive while there's
  clear non-saturation signal.

* Restructure code for clarity and add comments.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Andy Newell <newella@fb.com>
Fixes: 7cd806a9a9 ("iocost: improve nr_lagging handling")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-05-14 09:32:09 -06:00
arch A set of fixes for x86 and objtool: 2020-04-19 11:58:32 -07:00
block iocost: don't let vrate run wild while there's no saturation signal 2020-05-14 09:32:09 -06:00
certs .gitignore: add SPDX License Identifier 2020-03-25 11:50:48 +01:00
crypto x86: update AS_* macros to binutils >=2.23, supporting ADX and AVX2 2020-04-09 00:12:48 +09:00
Documentation hwmon fixes for v5.7-rc2 2020-04-18 13:28:09 -07:00
drivers null_blk: Support REQ_OP_ZONE_APPEND 2020-05-12 20:36:28 -06:00
fs zonefs: use REQ_OP_ZONE_APPEND for sync DIO 2020-05-12 20:36:28 -06:00
include block: move blk_io_schedule() out of header file 2020-05-14 08:06:04 -06:00
init Kbuild updates for v5.7 (2nd) 2020-04-11 09:46:12 -07:00
ipc ipc/util.c: sysvipc_find_ipc() should increase position index 2020-04-10 15:36:22 -07:00
kernel An update for the proc interface of time namespaces: Use symbolic names 2020-04-19 11:46:21 -07:00
lib Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-04-16 14:52:29 -07:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
mm bdi: remove the name field in struct backing_dev_info 2020-05-09 16:15:13 -06:00
net Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-04-16 14:52:29 -07:00
samples samples/hw_breakpoint: drop use of kallsyms_lookup_name() 2020-04-07 10:43:44 -07:00
scripts A handful of fixes for reasonably obnoxious documentation issues. 2020-04-17 13:10:50 -07:00
security selinux/stable-5.7 PR 20200416 2020-04-16 10:45:47 -07:00
sound sound fixes for 5.7-rc2 2020-04-17 09:48:50 -07:00
tools Merge branch 'block-5.7' into for-5.8/block 2020-05-09 16:13:58 -06:00
usr kbuild: fix comment about missing include guard detection 2020-04-11 12:09:48 +09:00
virt KVM: Pass kvm_init()'s opaque param to additional arch funcs 2020-03-31 10:48:03 -04:00
.clang-format clang-format: Update with the latest for_each macro list 2020-03-06 21:50:05 +01:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore .gitignore: add SPDX License Identifier 2020-03-25 11:50:48 +01:00
.mailmap mailmap: Add Sedat Dilek (replacement for expired email address) 2020-04-11 09:28:34 -07:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Hand MIPS over to Thomas 2020-02-24 22:43:18 -08:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig docs: kbuild: convert docs to ReST and rename to *.rst 2019-06-14 14:21:21 -06:00
MAINTAINERS SCSI fixes on 20200418 2020-04-18 14:03:12 -07:00
Makefile Linux 5.7-rc2 2020-04-19 14:35:30 -07:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

README 

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.