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7be835694d
util means the percentage that disk has IO, and theoretically it should not be greater than 100%. However, there is a gap for rq-based disk: io_ticks will be updated when rq is allocated, however, before such rq dispatch to driver, it will not be account as inflight from blk_mq_start_request() hence diskstats_show()/part_stat_show() will not update io_ticks. For example: 1) at t0, issue a new IO, rq is allocated, and blk_account_io_start() update io_ticks; 2) something is wrong with drivers, and the rq can't be dispatched; 3) at t0 + 10s, drivers recovers and rq is dispatched and done, io_ticks is updated; Then if user is using "iostat 1" to monitor "util", between t0 - t0+9s, util will be zero, and between t0+9s - t0+10s, util will be 1000%. Fix this problem by updating io_ticks from diskstats_show() and part_stat_show() if there are rq allocated. Signed-off-by: Yu Kuai <yukuai3@huawei.com> Link: https://lore.kernel.org/r/20240509123717.3223892-3-yukuai1@huaweicloud.com Signed-off-by: Jens Axboe <axboe@kernel.dk> |
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| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| io_uring | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| rust | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .editorconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| .rustfmt.toml | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| 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 reStructuredText 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.