2021 年合并了大量的内核改进，并引入了新的硬件支持等等。然而尽管这一年 Linux 内核中的动静看起来声势不错，但其实际上的 commit 数和行数都要低于以往。A large number of kernel improvements were merged in 2021, and new hardware support was introduced and so on. However, although the dynamics in the Linux kernel this year look good, the actual number of commits and the number of rows are lower than in the past.
The technology website phoronix summarized the relevant 2021 Git development statistics. As of December 31, 2021, when GitStats was run on the Linux kernel source tree, the repository had received 1,060,172 commits from approximately 243,000 different authors. The source code tree currently consists of 32.2 million lines in a 74.3k file.
The number of Linux kernel lines continues to grow at a fairly consistent rate, new features continue to emerge, and expanded hardware support reaches the mainline.
Although some major features were added and hardware support was introduced in 2021, the kernel only saw 73.7k commits in 2021, which is lower than 90.2k in 2020, 82.8k in 2019, and 80.1 in 2018 k and so on. The last time the number of commits in a single year was less than 73.7k was back to 2013, when the number of commits was 70.9k. Phoronix pointed out that part of the reason for this data is that only 5 major kernel versions were released in 2021, compared to 6 in previous years. The additional merge window has led to a large number of new commits; in addition, Linux 5.16 is scheduled to be released in a few weeks, which will launch the Linux 5.17 merge window in January.
In addition to the much fewer commits than usual, the Linux kernel added 3.2 million rows and deleted 1.3 million rows in 2021, which is lower than the increase of 4 million rows and 1.5 million rows deleted in 2020.
As usual, Linus Torvalds remains the most prolific committer in the source tree. The top five committers of the subsequent Linux kernel source code tree are David S. Miller, Arnd Bergmann, Christoph Hellwig, Lee Jones and Jakub Kicinski and other long-term outstanding kernel contributors.
In 2021, there were 4,421 different emails related to Linux kernel commits, which is lower than the 4,603 in 2020, but an increase from 4,383 in 2019.
科技网站 phoronix 总结了一下相关的 2021 年度 Git 开发统计数据。截至 2021 年 12 月 31 日，在 Linux 内核源码树上运行 GitStats 时，该存储库已收到来自大约 24.3 万名不同作者的 1,060,172 次 commit。源代码树目前由 74.3k 文件中的 3220 万行组成。
虽然在 2021 年新增了一些重大功能并引入了硬件支持，但内核在 2021 年却只看到了 73.7k 次 commit，要低于 2020 年的 90.2k、2019 年的 82.8k、2018 年的 80.1k 等等。上一次单年 commit 数低于 73.7k 的还要追溯到 2013年，当时的 commit 数为 70.9k。phoronix 指出，导致这一数据的部分原因在于 2021 年只有 5 个主要内核版本发布，此前的一些年份却有 6 个。额外的合并窗口导致了大量的新 commit；此外还有 Linux 5.16 计划于几周后发布，这将在 1 月份启动 Linux 5.17 合并窗口。
除了比平时少得多的 commit 数之外，2021 年 Linux 内核增加了 320 万行，删除了 130 万行，低于 2020 年增加 400 万行和删除 150 万行。
像往常一样，Linus Torvalds 依旧是源代码树中最多产的 committer。其后的 Linux 内核源代码树的前五名提交者是 David S. Miller、Arnd Bergmann、Christoph Hellwig、Lee Jones 和 Jakub Kicinski 等长期杰出内核贡献者。
2021 年有 4,421 封与 Linux kernel commits 相关的不同电子邮件，低于 2020 年的 4,603 封，但与 2019 年的 4,383 封相比有所增加。