If you’re not aware of what preload is, it’s a command line application that allows you to add files to ram, so they can be accessed faster by the applications that need them.
It seems to work well for what I’m using it for, which is to run games from slower storage devices, but there doesn’t seem to be any documentation for a proper way to remove the files once they’ve been added to ram. What I’ve been doing is to just use htop to terminate the preload command, but I feel like this is not intended at all. Is there a better way to remove these files?
I should mention that while trying to search for a solution myself, I did see gopreload mentioned a few times. I would try this out myself, but there’s no proper installation instructions, at least not any I could find that work in Linux Mint.
My understanding is the kernel will remove them if it needs the ram, so there is no need unless it’s for security reasons.
Usually, RAM space gets reserved, it doesn’t get removed then.
When you say “remove”, do you mean completely remove or move them to swap/zswap/zram, depending on what the system has enabled?
Cached files are freeable so the kernel will drop them instead of sending them to swap.
And I’m pretty sure zram is just a swap device in RAM so should follow the same rules.
Are we talking about this preload?
https://manpages.ubuntu.com/manpages/jammy/man8/preload.8.html
Cause if so, it doesn’t actually let you manually add specific files to RAM. It’s an adaptive daemon that automatically learns which files your applications use frequently over time and prefetches them. So when you launch it and then play games, it’s observing patterns and making predictions.
This also explains why there’s no “remove files” command. The files preload loads into RAM aren’t locked there; they’re in the page cache, which the kernel manages freely. If something else needs that memory, the kernel will evict those cached files automatically. Killing preload via htop should not really do anything, except it not doing it’s thing anymore.
When I used preload, it let me manually add files to ram. I used
sudo preload filenamefor each file (the game I tried it with only had two) and it seemed to add them to ram. I know this because the game had hitching issues even after just adding the main executable but the hitching went away when I added the second file.When you open and read files from a program the OS (kernel) will typically cache part or all of those files in memory. This is to speed up subsequent reads of that file since disk access is slow.
“preload” seems to be making use of that feature.
The kernel maintains this cache and evicts (unloads) things from it as needed. You don’t need to worry about it.
This doesn’t really prove it.
Running ths game multiple times will do the same, because the pages will stay cached. Operating systems are smart with RAM. Things that were recently used stay in RAM, even though the OS reports it being “free”. Read this for some more info: https://www.linuxatemyram.com/
And preload might swallow the filepath arg without doing anything with it.
Instead you could share the output of
preload --help preload --version sudo preload --verbose # followed by running a gameWhat you describe can actually be done with another tool https://hoytech.com/vmtouch but not with preload.
