The big picture
---------------
-The kernel developers use a loosely time-based release process, with a new
-major kernel release happening every two or three months. The recent
-release history looks like this:
-
- ====== =================
- 5.0 March 3, 2019
- 5.1 May 5, 2019
- 5.2 July 7, 2019
- 5.3 September 15, 2019
- 5.4 November 24, 2019
- 5.5 January 6, 2020
- ====== =================
-
-Every 5.x release is a major kernel release with new features, internal
-API changes, and more. A typical release can contain about 13,000
-changesets with changes to several hundred thousand lines of code. 5.x is
-the leading edge of Linux kernel development; the kernel uses a
-rolling development model which is continually integrating major changes.
+The Linux kernel uses a loosely time-based, rolling release development
+model. A new major kernel release (which we will call, as an example, 9.x)
+[1]_ happens every two or three months, which comes with new features,
+internal API changes, and more. A typical release can contain about 13,000
+changesets with changes to several hundred thousand lines of code. Recent
+releases, along with their dates, can be found at `Wikipedia
+<https://en.wikipedia.org/wiki/Linux_kernel_version_history>`_.
+
+.. [1] Strictly speaking, the Linux kernel does not use semantic versioning
+ number scheme, but rather the 9.x pair identifies major release
+ version as a whole number. For each release, x is incremented,
+ but 9 is incremented only if x is deemed large enough (e.g.
+ Linux 5.0 is released following Linux 4.20).
A relatively straightforward discipline is followed with regard to the
merging of patches for each release. At the beginning of each development
The merge window lasts for approximately two weeks. At the end of this
time, Linus Torvalds will declare that the window is closed and release the
-first of the "rc" kernels. For the kernel which is destined to be 5.6,
+first of the "rc" kernels. For the kernel which is destined to be 9.x,
for example, the release which happens at the end of the merge window will
-be called 5.6-rc1. The -rc1 release is the signal that the time to
+be called 9.x-rc1. The -rc1 release is the signal that the time to
merge new features has passed, and that the time to stabilize the next
kernel has begun.
achieve; there are just too many variables in a project of this size.
There comes a point where delaying the final release just makes the problem
worse; the pile of changes waiting for the next merge window will grow
-larger, creating even more regressions the next time around. So most 5.x
-kernels go out with a handful of known regressions though, hopefully, none
-of them are serious.
+larger, creating even more regressions the next time around. So most kernels
+go out with a handful of known regressions, though, hopefully, none of them
+are serious.
Once a stable release is made, its ongoing maintenance is passed off to the
"stable team," currently Greg Kroah-Hartman. The stable team will release
-occasional updates to the stable release using the 5.x.y numbering scheme.
+occasional updates to the stable release using the 9.x.y numbering scheme.
To be considered for an update release, a patch must (1) fix a significant
bug, and (2) already be merged into the mainline for the next development
kernel. Kernels will typically receive stable updates for a little more