2d ago

System requirements for me and not for thee

Possibly related:

I also don't understand why every chat app needs 1GB of RAM to itself.

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Many people who don't know what they're talking about in this thread. No, used memory does not include cached memory. You can confirm this trivially by running free -m and adding up the numbers (used + cached + free = total). Used memory can not be reclaimed until the process holding it frees it or dies. Not all cached memory can be reclaimed either, which is why the kernel reports an estimate of available memory. That's the number that really matters, because aside from some edges cases that's the number that determines whether you're out of memory or not.
Anyway the fact that you can't run Linux with 16GB is weird and indicates that some software you are using has a RAM leak (a Firefox extension perhaps?). Firefox will use memory if it's there but it's designed to cope with low memory as well, it just unloads tabs quicker so you have to reload often. There are also extensions that make tab unloading more aggressive, maybe that would help - especially if there's memory pressure from other processes too.
- Yeah the cache as part of used memory theory didn't stack up. This comment (sorry, Lemmy probably doesn't handle the link well) showed 54GB in use, 30GB cached, and 13GB available. 54+12 = 67GB total so cached doesn't seem to be counted as in use since it should be counted as free (mostly).
  In the end, I'm pretty sure it's a memory hog website. It kept filling up until GNOME crashed and I lost my progress (I was trying to order prints for 1000 photos on a horrible website that made me change settings one photo at a time, and the longer I took the more RAM filled up).
  Anyway the fact that you can’t run Linux with 16GB is weird
  I mean, it runs fine. It's more how I'm using it. Firefox 4GB, Element 1GB, Signal 1GB, Beeper 1GB, Steam 2GB, Joplin 1GB. That's all just open and idle (chats and Steam don't even have windows, just background) and are the minimum I would have open at any point. That's already 10GB. By the time I open a couple of windows in a Jetbrains IDE or a particularly demanding website and suddenly it's suffocating.

I have a memory consumption issue with Ubuntu, because I stupidly set up the system to have 0 swap. This means under high memory pressure, the entire system could suddenly crash.
To be fair, Windows isn't a shining beacon either because whenever I attempt something very GPU intensive like running local LLMs the GPU overheats in a split second before the fans have time to spin up and the entire system shuts down.
- Just enable zram. It's super easy to set up too.
  
  How do I do that?
- How does that happen? Shouldn't the GPU and CPU have thermal throttling so even under intense loads it just slows down to keep temps down?
  When I play games on my laptop the integrated graphics are at 100% most of the time but it doesn't cause the system to crash.
  
  So the system is a gaming laptop which might explain things. The CPU has liquid metal for cooling and a lower TDP so it's fine. Whereas the GPU has a higher TGP and if ran hard draws like 120W. If the GPU fans are not already on this quickly overwhelming the GPU thermally.

many Linux distros are optimized to use as much available RAM as possible, free RAM is wasted RAM
Most would still run with a lot less anyway
- Mine was definitely not handling 16GB...
  
  what do you mean? not working well with 16 gb??

https://www.linuxatemyram.com/
Electron apps are bullshit though.
- This site says Linux calls cached RAM "free" but in my screen shot it's definitely being shown as "used". I guess this is a choice of this app?
  
  Most likely, try running htop or top (can't remember which is which) in a terminal.

Hey, unused memory is wasted memory
- If you got it, flaunt it.
- If by "unused" you mean not actively storing data, then the Linux kernel docs disagree.
  vm.min_free_kbytes

every chat app might use ~1GB because most of them are electron apps, which all spawn their own instance of chromium
- I love how out of every single graphics backend option they chose the chromium Chrome is known for not slowing down after 3 tabs.
- Ah that makes sense.

Solution: if you only have 4GB ram, nothing can use more than 4GB
- It absolutely will try, it just gets killed by the oom reaper.
  
  Unless you have the vm.overcommit_memory sysctl set to 2, and your overcommit is set to less than your system memory.
  Then, when an application requests more memory than you have available, it will just get an error instead of needing to be killed by OOM when it attempts to use the memory at a later time.
  
  I've used Linux for years and never in my life have I seen anything crash or close because of a oom killer. It's myth for me that it exists. Me looking at my firefox occupying 6GB of the 8GB ram and opening intellij so it becomes full and swap is on 3GB.
- /swapfile joined the chat
- I had one stick of 16GB and it was not enough. I was going to get a second stick, but said screw it and got two 32GB (it's a laptop and only has two slots).
  
  How does that even happen 💀💀 I have 2x8gb, usually have teams open, Firefox, telegram, a virtual machine with windows 10, a few IDEs and it usually only takes 10-12gb max mostly due to the vm requiring flat 8 gigs
  
  How does 2 x 32 GB sticks give you 67 GB of RAM? Did you download more RAM?
- Depends on how much /swap you've got.

It's already been explained elsewhere, but the cache can be free, as needed - that's how linux works.
There's 57+ GB available ram, yet.
- Yip, got that now. I misunderstood, as it's different to Windows, which shows cached memory as free since it's available to apps as needed.
  
  You could probably configure your system monitor to show available memory - that is memory available given that cache can be dropped - rather than free memory that should always be as close to zero as possible.

18gb is nothing, my Firefox regularly eats 70gb (30gb is the normal load I see after browser restart)
- I don't know if this is something to brag about, it seems more like something isn't working right...
- Browser restart means without any tabs? If so that is some concern
- What are you doing to poor Firefox?
  
  Firefox with an inflation fetish
- How do you do this? I usually have about 2k open tabs and my firefox uses a fraction of that.
- Wait, everyone is saying cached is part of the used memory but yours shows more cached than in use?

Don't be confused by cached ram, be confused by the oom killer activating while you have plenty of swap and for some reason it kills the shell you ran Firefox from.
If you want to go on a memory allocation adventure try disabling memory overcommit 🥲
- systemd-oomd with its memory pressure model never really worked for me, even after configuring it to be fairly aggressive. My system still irreversibly locks up the second the memory and swap touches 100%. earlyoom with its more primitive model works much better and actually kills processes before the memory and swap hits the ceiling. Combine this with a 2x RAM size swap file and desktop Linux is finally as stable as Windows and macOS. It is just a shame that distros do not configure generous, dynamically growing, swap files and a good oom killer by default, and you have to discover this fundamental problem of the Linux kernel yourself on multiple different devices before realizing what you actually need to do to fix these random freezes.
- If you're out of ram and using swap thats when the oom killer should be killing. Swap is not ram.
  
  Unless you use zram. Compressing pages is pretty useful as an intermediate stage.

Does it mean 35.1 GB out of the 44.3 GB is actually cached? Then you have quite low actual RAM usage considering you have 67 GB.
- Oh good question. Now I'm wondering. 44+35 is bigger than the 67GB I have, but normally I would expect pretty much all the RAM to hold cached data, where some is also marked as free in case a process needs it.
  Can someone explain this memory screen, as your question has raised many more for me!
  
  “Cache” means space used for disk caching. It’s free to be used for processes as needed, but the system consumes idle RAM until then to speed things up, so it’s technically not “free”, even though it isn’t used by system processes. In Linux, used - cache gives you the actual consumption by processes.

oh i see you're also using a single tab for youtube and no other tabs

Most RAM Linux reports as in used is actually used as disc cache to speed up the IO.
- Well having 64GB RAM has been a huge boost to how fast everything feels so this checks out.
  
  I remember having 64kb, and it was large...

~19 Gb firefox
Tf you doing
- The about:processes page doesn't even add up close to that:
  
  Then it's just a bug I guess
  Or someone is getting very rich in bitcoin right now
- I need those tabs for... uhhhh...

Me when I load some big matrices

I had a power surge last night, desktop didn't even flinch.

My first thought was that it was running a windows vm…
- Nope, I don't have a windows VM at all.

What are you doing?
- You don't want to know
  
  Welp I have 64gb of ram and I only ever use that much running llms.

It do be like that

Windows shows memory used for cache as free. Linux per default shows it as used.
Try free -m
Also I would disable swap, it is no longer 2004.
- It is also used for system suspend.
  Disabling swap will prevent a system from suspending, which might be fine, but I use it.
  And swap isn't some ancient relic. Sure, my 32GB desktop barely uses it, but my home server benefits greatly from having 64GB of swap in addition to 16GB of physical memory. It may not need to use much more than 16GB at any one time, but shit runs a lot better using a giant SSD swap with how many services I run.
  System config is case by case, not "current year".
  @Dave@lemmy.nz
- Windows shows memory used for cache as free. Linux per default shows it as used.
  Ah thanks for the explanation!
  Also I would disable swap, it is no longer 2004.
  I'm using Bazzite as of recently, and learnt the first day not to touch the system. Anyway, it's zram not an on disk swap file.
  
  It depends on the application used as some show cached as used and some don't. But it is being more common to not show cached as used.

100 comments