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Merge tag 'io_uring-2019-03-06' of git://git.kernel.dk/linux-block

Pull io_uring IO interface from Jens Axboe:
 "Second attempt at adding the io_uring interface.

  Since the first one, we've added basic unit testing of the three
  system calls, that resides in liburing like the other unit tests that
  we have so far. It'll take a while to get full coverage of it, but
  we're working towards it. I've also added two basic test programs to
  tools/io_uring. One uses the raw interface and has support for all the
  various features that io_uring supports outside of standard IO, like
  fixed files, fixed IO buffers, and polled IO. The other uses the
  liburing API, and is a simplified version of cp(1).

  This adds support for a new IO interface, io_uring.

  io_uring allows an application to communicate with the kernel through
  two rings, the submission queue (SQ) and completion queue (CQ) ring.
  This allows for very efficient handling of IOs, see the v5 posting for
  some basic numbers:

    https://lore.kernel.org/linux-block/20190116175003.17880-1-axboe@kernel.dk/

  Outside of just efficiency, the interface is also flexible and
  extendable, and allows for future use cases like the upcoming NVMe
  key-value store API, networked IO, and so on. It also supports async
  buffered IO, something that we've always failed to support in the
  kernel.

  Outside of basic IO features, it supports async polled IO as well.
  This particular feature has already been tested at Facebook months ago
  for flash storage boxes, with 25-33% improvements. It makes polled IO
  actually useful for real world use cases, where even basic flash sees
  a nice win in terms of efficiency, latency, and performance. These
  boxes were IOPS bound before, now they are not.

  This series adds three new system calls. One for setting up an
  io_uring instance (io_uring_setup(2)), one for submitting/completing
  IO (io_uring_enter(2)), and one for aux functions like registrating
  file sets, buffers, etc (io_uring_register(2)). Through the help of
  Arnd, I've coordinated the syscall numbers so merge on that front
  should be painless.

  Jon did a writeup of the interface a while back, which (except for
  minor details that have been tweaked) is still accurate. Find that
  here:

    https://lwn.net/Articles/776703/

  Huge thanks to Al Viro for helping getting the reference cycle code
  correct, and to Jann Horn for his extensive reviews focused on both
  security and bugs in general.

  There's a userspace library that provides basic functionality for
  applications that don't need or want to care about how to fiddle with
  the rings directly. It has helpers to allow applications to easily set
  up an io_uring instance, and submit/complete IO through it without
  knowing about the intricacies of the rings. It also includes man pages
  (thanks to Jeff Moyer), and will continue to grow support helper
  functions and features as time progresses. Find it here:

    git://git.kernel.dk/liburing

  Fio has full support for the raw interface, both in the form of an IO
  engine (io_uring), but also with a small test application (t/io_uring)
  that can exercise and benchmark the interface"

* tag 'io_uring-2019-03-06' of git://git.kernel.dk/linux-block:
  io_uring: add a few test tools
  io_uring: allow workqueue item to handle multiple buffered requests
  io_uring: add support for IORING_OP_POLL
  io_uring: add io_kiocb ref count
  io_uring: add submission polling
  io_uring: add file set registration
  net: split out functions related to registering inflight socket files
  io_uring: add support for pre-mapped user IO buffers
  block: implement bio helper to add iter bvec pages to bio
  io_uring: batch io_kiocb allocation
  io_uring: use fget/fput_many() for file references
  fs: add fget_many() and fput_many()
  io_uring: support for IO polling
  io_uring: add fsync support
  Add io_uring IO interface
2019-03-08 14:48:40 -08:00
arch io_uring-2019-03-06 2019-03-08 14:48:40 -08:00
block io_uring-2019-03-06 2019-03-08 14:48:40 -08:00
certs kbuild: remove redundant target cleaning on failure 2019-01-06 09:46:51 +09:00
crypto lib/lzo: separate lzo-rle from lzo 2019-03-07 18:32:03 -08:00
Documentation for-5.1/block-20190302 2019-03-08 14:12:17 -08:00
drivers for-5.1/block-20190302 2019-03-08 14:12:17 -08:00
fs io_uring-2019-03-06 2019-03-08 14:48:40 -08:00
include io_uring-2019-03-06 2019-03-08 14:48:40 -08:00
init io_uring-2019-03-06 2019-03-08 14:48:40 -08:00
ipc ipc/sem.c: replace kvmalloc/memset with kvzalloc and use struct_size 2019-03-07 18:32:02 -08:00
kernel io_uring-2019-03-06 2019-03-08 14:48:40 -08:00
lib Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/livepatching/livepatching 2019-03-08 08:58:25 -08:00
LICENSES This is a fairly typical cycle for documentation. There's some welcome 2018-10-24 18:01:11 +01:00
mm Merge branch 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-03-07 17:43:58 -08:00
net io_uring-2019-03-06 2019-03-08 14:48:40 -08:00
samples Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/livepatching/livepatching 2019-03-08 08:58:25 -08:00
scripts scripts/gdb: replace flags (MS_xyz -> SB_xyz) 2019-03-07 18:32:02 -08:00
security audit/stable-5.1 PR 20190305 2019-03-07 12:20:11 -08:00
sound Char/Misc driver patches for 5.1-rc1 2019-03-06 14:18:59 -08:00
tools io_uring-2019-03-06 2019-03-08 14:48:40 -08:00
usr user/Makefile: Fix typo and capitalization in comment section 2018-12-11 00:18:03 +09:00
virt ACPI updates for 5.1-rc1 2019-03-06 13:33:11 -08:00
.clang-format clang-format: Update .clang-format with the latest for_each macro list 2019-01-19 19:26:06 +01:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Add hch to .get_maintainer.ignore 2015-08-21 14:30:10 -07:00
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore kbuild: Add support for DT binding schema checks 2018-12-13 09:41:32 -06:00
.mailmap .mailmap: Add Mathieu Othacehe 2019-02-21 11:41:19 +00:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS Char/Misc driver patches for 5.1-rc1 2019-03-06 14:18:59 -08:00
Kbuild Merge branch 'locking/atomics' into locking/core, to pick up WIP commits 2019-02-11 14:27:05 +01:00
Kconfig kconfig: move the "Executable file formats" menu to fs/Kconfig.binfmt 2018-08-02 08:06:55 +09:00
MAINTAINERS This is the bulk of GPIO changes for the v5.1 cycle: 2019-03-08 10:09:53 -08:00
Makefile Driver core patches for 5.1-rc1 2019-03-06 14:52:48 -08:00
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.