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A deep dive into Debian 13 /tmp: What's new, and what to do if you don't like it

(lowendbox.com)
150 points shaunpud | 1 comments | 29 Aug 25 02:39 UTC | HN request time: 0s | source
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ars ◴[29 Aug 25 04:24 UTC] No.45060177[source]▶
File is tmpfs will swap out if your system is under memory pressure.

If that happens, reading the file back is DRAMATICALLY slower than if you had just stored the file on disk in the first place.

This change is not going to speed things up for most users, it will slow things. Instead of caching important files, you waste memory on useless temporary files. Then the system swaps it out, so you can get cache back, and then it's really slow to read back.

This change is a mistake.

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saurik ◴[29 Aug 25 04:30 UTC] No.45060209[source]▶
Why is reading the data back from swap be slower at all -- much less "DRAMATICALLY" so -- than saving the data to disk and reading it back?
replies(1): >>45060257 #
cwillu ◴[29 Aug 25 04:38 UTC] No.45060257[source]▶
Because swapping back in happens 4kb at a time
replies(2): >>45060816 #>>45061751 #
cycomanic ◴[29 Aug 25 06:21 UTC] No.45060816[source]▶
Why?
replies(1): >>45060871 #
1. worthless-trash ◴[29 Aug 25 06:29 UTC] No.45060871{3}[source]▶
Because of page size. Its treated like any other page.