That's the original date on the file, but the comment being discussed (and much of the code in that function, it seems) was from 17 years ago. See the git-blame:

https://github.com/torvalds/linux/blame/f4bc5bbb5fef3cf421ba...

See the text of the comment: "12/12/91". The `git blame` is likely due to not having imported the previous history as commits when the original import to the git repo happened. I worked at a company that moved from VSS to TFS for a ~10 year code base. It took months for the consultants to get the import to preserve the history. Too bad this didn't happen in this repo.

edit: Found this [0]

  Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it.

  Let it rip!

0: https://github.com/torvalds/linux/commit/1da177e4c3f41524e88...

Linus was in the middle of designing git when he wrote this. I think we can cut him some slack.

That commit seems to include all the code written before 2005. The commit message notes that it doesn't bother including the full history.

The comment says 12/12/91

Ha ha. Yeah Linus worked on Linux before Git unfortunately. Or fortunately maybe (because the world needed Linux before it needed git)

Thanks for making me feel old.

Yes but git-blame shows 17 years ago.

Git was released 7 April 2005, I imagine it existed and was used before v1.0 release, so 17 years checks out. It is git's age, not the code.

Yes, but some of the history has been omitted. [1] Line 1035 includes the signoff "-TYT, 12/1291"

1. https://github.com/torvalds/linux/commit/1da177e4c3f41524e88...