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Richard Yao 0e4c830bc1
Cleanup: Use OpenSolaris functions to call scheduler
In our codebase, `cond_resched() and `schedule()` are Linux kernel
functions that have replaced the OpenSolaris `kpreempt()` functions in
the codebase to such an extent that `kpreempt()` in zfs_context.h was
broken. Nobody noticed because we did not actually use it. The header
had defined `kpreempt()` as `yield()`, which works on OpenSolaris and
Illumos where `sched_yield()` is a wrapper for `yield()`, but that does
not work on any other platform.

The FreeBSD platform specific code implemented shims for these, but the
shim for `schedule()` forced us to wait, which is different than merely
rescheduling to another thread as the original Linux code does, while
the shim for `cond_resched()` had the same definition as its kernel
kpreempt() shim.

After studying this, I have concluded that we should reintroduce the
kpreempt() function in platform independent code with the following
definitions:

	- In the Linux kernel:
		kpreempt(unused)	-> cond_resched()

	- In the FreeBSD kernel:
		kpreempt(unused)	-> kern_yield(PRI_USER)

	- In userspace:
		kpreempt(unused)	-> sched_yield()

In userspace, nothing changes from this cleanup. In the kernels, the
function `fm_fini()` will now call `kern_yield(PRI_USER)` on FreeBSD and
`cond_resched()` on Linux.  This is instead of `pause("schedule", 1)` on
FreeBSD and `schedule()` on Linux. This makes our behavior consistent
across platforms.

Note that Linux's SPL continues to use `cond_resched()` and
`schedule()`.  However, those functions have been removed from both the
FreeBSD code and userspace code.

This should have the benefit of making it slightly easier to port the
code to new platforms by making how things should be mapped less
confusing.

Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Neal Gompa <ngompa@datto.com>
Signed-off-by: Richard Yao <richard.yao@alumni.stonybrook.edu>
Closes #13845
2022-09-12 09:55:37 -07:00
.github Replace EXTRA_DIST with dist_noinst_DATA 2022-05-26 09:24:50 -07:00
cmd Make zfs-share service resilient to stale exports 2022-09-09 10:54:16 -07:00
config Add Linux posix_fadvise support 2022-09-08 10:29:41 -07:00
contrib contrib: dracut: zfs-snapshot-bootfs: exit status fix 2022-08-12 14:28:15 -07:00
etc Make zfs-share service resilient to stale exports 2022-09-09 10:54:16 -07:00
include Cleanup: Use OpenSolaris functions to call scheduler 2022-09-12 09:55:37 -07:00
lib Make zfs-share service resilient to stale exports 2022-09-09 10:54:16 -07:00
man Improve too large physical ashift handling 2022-09-08 10:30:53 -07:00
module Cleanup: Use OpenSolaris functions to call scheduler 2022-09-12 09:55:37 -07:00
rpm Add zilstat script to report zil kstats in a user friendly manner 2022-09-02 13:24:07 -07:00
scripts Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
tests Improve too large physical ashift handling 2022-09-08 10:30:53 -07:00
udev Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
.editorconfig Add an .editorconfig; document git whitespace settings 2020-01-27 13:32:52 -08:00
.gitignore autoconf: use include directives instead of recursing down cmd 2022-05-10 10:18:38 -07:00
.gitmodules .gitmodules: link to openzfs github repository 2021-04-12 09:37:23 -07:00
AUTHORS Introduce BLAKE3 checksums as an OpenZFS feature 2022-06-08 15:55:57 -07:00
autogen.sh autogen.sh: paper over automake <1.14's lack of %reldir% support 2022-05-10 10:20:46 -07:00
CODE_OF_CONDUCT.md Replace ZFS on Linux references with OpenZFS 2020-10-08 20:10:13 -07:00
configure.ac Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
copy-builtin copy-builtin: add hooks with sed/>> 2022-05-10 10:17:43 -07:00
COPYRIGHT Fix typos 2020-06-09 21:24:09 -07:00
LICENSE Update build system and packaging 2018-05-29 16:00:33 -07:00
Makefile.am Replace EXTRA_DIST with dist_noinst_DATA 2022-05-26 09:24:50 -07:00
META Linux 5.19 compat: META 2022-08-02 10:04:38 -07:00
NEWS Fix NEWS file 2020-08-26 21:44:41 -07:00
NOTICE Update build system and packaging 2018-05-29 16:00:33 -07:00
README.md README: Update OpenZFS website url 2022-01-06 16:25:01 -08:00
RELEASES.md Add RELEASES.md file 2021-04-02 16:33:40 -07:00
TEST Remove CI builder customization from TEST 2020-03-16 10:46:03 -07:00
zfs.release.in Move zfs.release generation to configure step 2012-07-12 12:22:51 -07:00

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OpenZFS is an advanced file system and volume manager which was originally developed for Solaris and is now maintained by the OpenZFS community. This repository contains the code for running OpenZFS on Linux and FreeBSD.

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Official Resources

Installation

Full documentation for installing OpenZFS on your favorite operating system can be found at the Getting Started Page.

Contribute & Develop

We have a separate document with contribution guidelines.

We have a Code of Conduct.

Release

OpenZFS is released under a CDDL license. For more details see the NOTICE, LICENSE and COPYRIGHT files; UCRL-CODE-235197

Supported Kernels

  • The META file contains the officially recognized supported Linux kernel versions.
  • Supported FreeBSD versions are any supported branches and releases starting from 12.2-RELEASE.