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Omar Sandoval b57e99b4b8 block: use nanosecond resolution for iostat
Klaus Kusche reported that the I/O busy time in /proc/diskstats was not
updating properly on 4.18. This is because we started using ktime to
track elapsed time, and we convert nanoseconds to jiffies when we update
the partition counter. However, this gets rounded down, so any I/Os that
take less than a jiffy are not accounted for. Previously in this case,
the value of jiffies would sometimes increment while we were doing I/O,
so at least some I/Os were accounted for.

Let's convert the stats to use nanoseconds internally. We still report
milliseconds as before, now more accurately than ever. The value is
still truncated to 32 bits for backwards compatibility.

Fixes: 522a777566 ("block: consolidate struct request timestamp fields")
Cc: stable@vger.kernel.org
Reported-by: Klaus Kusche <klaus.kusche@computerix.info>
Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-09-21 20:26:59 -06:00
Documentation Merge branch 'stable/for-jens-4.19' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen into for-linus 2018-08-27 11:27:32 -06:00
LICENSES LICENSES: Add Linux-OpenIB license text 2018-04-27 16:41:53 -06:00
arch IOMMU Update for Linux v4.19 2018-08-24 13:10:38 -07:00
block block: use nanosecond resolution for iostat 2018-09-21 20:26:59 -06:00
certs Replace magic for trusting the secondary keyring with #define 2018-08-16 09:57:20 -07:00
crypto DMAengine updates for v4.19-rc1 2018-08-18 15:55:59 -07:00
drivers Merge branch 'nvme-4.19' of git://git.infradead.org/nvme into for-linus 2018-09-20 09:10:38 -06:00
firmware kbuild: remove all dummy assignments to obj- 2017-11-18 11:46:06 +09:00
fs This pull request contains a single fix for UBIFS: 2018-08-25 13:27:35 -07:00
include block: use nanosecond resolution for iostat 2018-09-21 20:26:59 -06:00
init Merge branch 'akpm' (patches from Andrew) 2018-08-22 12:34:08 -07:00
ipc ipc/util.c: update return value of ipc_getref from int to bool 2018-08-22 10:52:52 -07:00
kernel Merge branch 'for-4.19' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup 2018-08-24 13:19:27 -07:00
lib lib/fonts: convert comments to utf-8 2018-08-23 18:48:43 -07:00
mm blkcg: delay blkg destruction until after writeback has finished 2018-08-31 14:48:56 -06:00
net Merge branch 'akpm' (patches from Andrew) 2018-08-23 19:20:12 -07:00
samples samples/bpf: all XDP samples should unload xdp/bpf prog on SIGTERM 2018-08-16 21:55:32 +02:00
scripts treewide: correct "differenciate" and "instanciate" typos 2018-08-23 18:48:43 -07:00
security + Cleanups 2018-08-24 13:00:33 -07:00
sound Merge branch 'akpm' (patches from Andrew) 2018-08-23 19:20:12 -07:00
tools treewide: convert ISO_8859-1 text comments to utf-8 2018-08-23 18:48:43 -07:00
usr kbuild: rename built-in.o to built-in.a 2018-03-26 02:01:19 +09:00
virt ARM: Support for Group0 interrupts in guests, Cache management 2018-08-22 13:52:44 -07:00
.clang-format clang-format: Set IndentWrappedFunctionNames false 2018-08-01 18:38:51 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore Kbuild updates for v4.17 (2nd) 2018-04-15 17:21:30 -07:00
.mailmap Merge branch 'linus/master' into rdma.git for-next 2018-08-16 14:21:29 -06:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS 9p: remove Ron Minnich from MAINTAINERS 2018-08-17 16:20:26 -07:00
Kbuild Kbuild updates for v4.15 2017-11-17 17:45:29 -08:00
Kconfig kconfig: move the "Executable file formats" menu to fs/Kconfig.binfmt 2018-08-02 08:06:55 +09:00
MAINTAINERS libata: maintainership update 2018-08-25 12:35:45 -07:00
Makefile Updates for v4.19: 2018-08-20 18:32:00 -07:00
README Docs: Added a pointer to the formatted docs to README 2018-03-21 09:02:53 -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.
See Documentation/00-INDEX for a list of what is contained in each file.

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.