Go to file
Tejun Heo aa67db24b6 iocost: fix infinite loop bug in adjust_inuse_and_calc_cost()
adjust_inuse_and_calc_cost() is responsible for reducing the amount of
donated weights dynamically in period as the budget runs low. Because we
don't want to do full donation calculation in period, we keep latching up
inuse by INUSE_ADJ_STEP_PCT of the active weight of the cgroup until the
resulting hweight_inuse is satisfactory.

Unfortunately, the adj_step calculation was reading the active weight before
acquiring ioc->lock. Because the current thread could have lost race to
activate the iocg to another thread before entering this function, it may
read the active weight as zero before acquiring ioc->lock. When this
happens, the adj_step is calculated as zero and the incremental adjustment
loop becomes an infinite one.

Fix it by fetching the active weight after acquiring ioc->lock.

Fixes: b0853ab4a2 ("blk-iocost: revamp in-period donation snapbacks")
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-14 17:25:39 -06:00
arch Three interrupt related fixes for X86: 2020-08-30 12:01:23 -07:00
block iocost: fix infinite loop bug in adjust_inuse_and_calc_cost() 2020-09-14 17:25:39 -06:00
certs .gitignore: add SPDX License Identifier 2020-03-25 11:50:48 +01:00
crypto Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2020-08-30 15:53:44 -07:00
Documentation Documentation/filesystems/locking.rst: remove an incorrect sentence 2020-09-02 07:59:59 -06:00
drivers bcache: use part_[begin|end]_io_acct instead of disk_[begin|end]_io_acct 2020-09-11 16:41:30 -06:00
fs block: remove check_disk_change 2020-09-10 09:32:31 -06:00
include block: introduce part_[begin|end]_io_acct 2020-09-11 16:41:30 -06:00
init OpenRISC updates for 5.9 2020-08-14 14:04:53 -07:00
ipc treewide: Use fallthrough pseudo-keyword 2020-08-23 17:36:59 -05:00
kernel blktrace: make function blk_trace_bio_get_cgid() static 2020-09-07 20:11:15 -06:00
lib lib: Revert use of fallthrough pseudo-keyword in lib/ 2020-08-24 14:17:44 -07:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
mm powerpc fixes for 5.9 #4 2020-08-30 10:56:12 -07:00
net Fixes: 2020-08-25 18:01:36 -07:00
samples treewide: Use fallthrough pseudo-keyword 2020-08-23 17:36:59 -05:00
scripts kconfig: qconf: replace deprecated QString::sprintf() with QTextStream 2020-08-21 10:23:38 +09:00
security treewide: Use fallthrough pseudo-keyword 2020-08-23 17:36:59 -05:00
sound treewide: Use fallthrough pseudo-keyword 2020-08-23 17:36:59 -05:00
tools blk-iocost: update iocost_monitor.py 2020-09-01 19:38:33 -06:00
usr Merge branch 'work.fdpic' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-08-07 13:29:39 -07:00
virt * PAE and PKU bugfixes for x86 2020-08-22 10:03:05 -07:00
.clang-format block: add bio_for_each_bvec_all() 2020-05-25 11:25:24 +02:00
.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 ZSTD-compressed files 2020-07-31 11:50:49 +02:00
.mailmap Merge branch 'akpm' (patches from Andrew) 2020-08-21 14:44:48 -07:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS CREDITS: Replace HTTP links with HTTPS ones 2020-07-23 14:53:58 -06:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS Three interrupt related fixes for X86: 2020-08-30 12:01:23 -07:00
Makefile Linux 5.9-rc3 2020-08-30 16:01:54 -07:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

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.