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Ming Lei 9f5ede3c01 block: throttle split bio in case of iops limit
Commit 111be88398 ("block-throttle: avoid double charge") marks bio as
BIO_THROTTLED unconditionally if __blk_throtl_bio() is called on this bio,
then this bio won't be called into __blk_throtl_bio() any more. This way
is to avoid double charge in case of bio splitting. It is reasonable for
read/write throughput limit, but not reasonable for IOPS limit because
block layer provides io accounting against split bio.

Chunguang Xu has already observed this issue and fixed it in commit
4f1e9630af ("blk-throtl: optimize IOPS throttle for large IO scenarios").
However, that patch only covers bio splitting in __blk_queue_split(), and
we have other kind of bio splitting, such as bio_split() &
submit_bio_noacct() and other ways.

This patch tries to fix the issue in one generic way by always charging
the bio for iops limit in blk_throtl_bio(). This way is reasonable:
re-submission & fast-cloned bio is charged if it is submitted to same
disk/queue, and BIO_THROTTLED will be cleared if bio->bi_bdev is changed.

This new approach can get much more smooth/stable iops limit compared with
commit 4f1e9630af ("blk-throtl: optimize IOPS throttle for large IO
scenarios") since that commit can't throttle current split bios actually.

Also this way won't cause new double bio iops charge in
blk_throtl_dispatch_work_fn() in which blk_throtl_bio() won't be called
any more.

Reported-by: Ning Li <lining2020x@163.com>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Chunguang Xu <brookxu@tencent.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20220216044514.2903784-7-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-02-16 19:42:28 -07:00
arch block: remove genhd.h 2022-02-02 07:49:59 -07:00
block block: throttle split bio in case of iops limit 2022-02-16 19:42:28 -07:00
certs certs: Fix build error when CONFIG_MODULE_SIG_KEY is empty 2022-01-23 00:08:44 +09:00
crypto lib/crypto: add prompts back to crypto libraries 2022-01-18 13:03:55 +01:00
Documentation block: remove biodoc.rst 2022-02-15 07:47:52 -07:00
drivers dm: remove dm_dispatch_clone_request 2022-02-16 19:39:10 -07:00
fs block: pass a block_device to bio_clone_fast 2022-02-04 07:43:18 -07:00
include blk-mq: remove the request_queue argument to blk_insert_cloned_request 2022-02-16 19:39:10 -07:00
init block: remove genhd.h 2022-02-02 07:49:59 -07:00
ipc proc: remove PDE_DATA() completely 2022-01-22 08:33:37 +02:00
kernel block: check that there is a plug in blk_flush_plug 2022-02-02 07:50:00 -07:00
lib sbitmap: Delete old sbitmap_queue_get_shallow() 2022-02-08 06:55:49 -07:00
LICENSES LICENSES/LGPL-2.1: Add LGPL-2.1-or-later as valid identifiers 2021-12-16 14:33:10 +01:00
mm block: pass a block_device and opf to bio_alloc 2022-02-02 07:49:59 -07:00
net \n 2022-01-28 17:51:31 +02:00
samples Merge branch 'akpm' (patches from Andrew) 2022-01-20 10:41:01 +02:00
scripts ftrace: Have architectures opt-in for mcount build time sorting 2022-01-27 19:15:44 -05:00
security block: remove genhd.h 2022-02-02 07:49:59 -07:00
sound proc: remove PDE_DATA() completely 2022-01-22 08:33:37 +02:00
tools tools/testing/scatterlist: add missing defines 2022-01-30 09:56:58 +02:00
usr kbuild: remove include/linux/cyclades.h from header file check 2022-01-27 08:51:08 +01:00
virt Two larger x86 series: 2022-01-28 19:00:26 +02:00
.clang-format genirq/msi: Make interrupt allocation less convoluted 2021-12-16 22:22:20 +01:00
.cocciconfig
.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: ignore only top-level modules.builtin 2021-05-02 00:43:35 +09:00
.mailmap mailmap: update email address of Brian Silverman 2022-01-24 18:27:23 +01:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Removing Ohad from remoteproc/rpmsg maintenance 2021-12-08 10:09:40 -07:00
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 MAINTAINERS: add bio.h to the block section 2022-02-02 07:50:00 -07:00
Makefile Linux 5.17-rc2 2022-01-30 15:37:07 +02:00
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.