[CLOSED] tmpfs/run weirdness with MGA3; need explanation.

[dedanna1029]

Hi, after installing MGA3, reinstalling / (root), I have something now that I didn't previously in MGA2, and would like to know how to disable it, that being all this tmpfs/cgroups weirdness. Is there a way I can reclaim what all is being allocated for other things here in / (root)? This is all something I could do completely without, there is no reason for any of it for me. I do a lot of installing; lots of things I use, so have a large / deliberately, and need all I can get of it (and RAM; I have 1GB of RAM, and things go slowly with all this sometimes). I didn't have to worry about this in MGA2 - cgroups wasn't there. It is now in MGA3. There are other things in this df that I don't understand, either. tmpfs overall totally completely eludes me; can anyone explain it please? There are three here, evidently all from/to the same place in root being allocated for things I don't care about. I also don't understand the /run thing when I plug in a usb device? Why can't it just mount in /media like usual (this was a confusion for me in MGA2 as well)? Some devices mount in a place called /run/myuser/media or something like that? Makes things very confusing for me. Is there a way to bypass the /run thing, and just have things mount simply to /media? I had everything exception of cgroups in MGA2, and didn't understand them then. I need now to know if there's also a way to disable cgroups.

Thanks!

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[root@dedanna ~]# df -h
Filesystem      Size  Used Avail Use% Mounted on
rootfs           39G   11G   29G  27% /
devtmpfs        492M     0  492M   0% /dev
--->tmpfs           499M  604K  498M   1% /dev/shm (weirdness)
--->tmpfs           499M  760K  498M   1% /run (weirdness)
/dev/sda1        39G   11G   29G  27% /
--->tmpfs           499M     0  499M   0% /sys/fs/cgroup (weirdness)
none            499M  5.7M  493M   2% /tmp
/dev/sda6       193G  117G   77G  61% /home

[doktor5000]

You're wrong, this was already the case for Mageia 2, it has mostly been introduced with the switch to systemd.
That was also even present earlier, but it was suppressed/not shown due to some magic filters which did only show "real" filesystems from /etc/mtab.
Now you also see all the pseudo-filesystems, it's not nice but nevertheless reality.

Basically everything that has tmpfs runs in RAM, those are only pseudo-filesystems. If you want to see the real filesystems,
use something like

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grep ^/ /etc/mtab

or

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df | grep ^/

If you want to know about this stuff, you may want to have a look at https://wiki.archlinux.org/index.php/Cgroups
and the mounting below /run/media/username/LABEL is now the default, sadly.

[dedanna1029]

Is there a CLI trick to change that default mount folder?

Yeah, I didn't see the cgroups in MGA2. I guess it doesn't mean it wasn't there. Need to find a way to disable it. I'm not all on fire about systemd either; would much rather the older systems (dracut, etc.?).

Thanks.

[doktor5000]

For default mount folder, not a proper way that i know of. You can have a look at the reasons and context upstream at https://bugs.freedesktop.org/show_bug.cgi?id=51709
Any particular reason why you want to change it, other then that you don't like it?

For cgroups, why do you need to find a way to disable it? And the old system is already gone (dracut has nothing to do with it, it only generates the initial ramdisk images used to boot Mageia)

[dedanna1029]

cgroups allocates RAM/whatever that is unnecessary for me, and having only limited / space, as well as RAM (as explained earlier), it is an allocation (actually, tmpfs is on the whole) that I don't need or want. It is something that will never be used, and I really don't like forced allocations for social cr@pola I won't use.

[sander85]

Well, the sad story for you is that systemd depends on cgroups. https://www.kernel.org/doc/Documentatio ... groups.txt - they are built-in future of kernel. There is no way you can disable them and still use your system.

[doktor5000]

cgroups allocates RAM/whatever that is unnecessary for me, and having only limited / space, as well as RAM [...] it is something that will never be used, and I really don't like forced allocations for social cr@pola I won't use.

Please prove that cgroups wastes memory on your box. Also what do you mean with "social cr@pola" ... ?

The same way you could also say that /proc wastes precious memory ...
First you want an explanation, then you're complaining, even if you don't really know what this is used for.
Sorry but that is just trolling, please stop it.

[dedanna1029]

https://www.kernel.org/doc/Documentatio ... groups.txt

A *subsystem* is a module that makes use of the task grouping
facilities provided by cgroups to treat groups of tasks in
particular ways. A subsystem is typically a "resource controller" that
schedules a resource or applies per-cgroup limits, but it may be
anything that wants to act on a group of processes, e.g. a
virtualization subsystem.

I do not need "resources controlled", nor do I need allocations for things I don't want. I'd like to control my resources for myself. We used to be able to do this with just /, /swap, /tmp, and /home.

This is NOT trolling. This "tmp thing" is allocating half of my RAM for something I don't need or want.

And yes, I have seen it referred as for "social" things; for others to use. Again, I don't need this. It's not a Mageia thing; it's a kernel thing which Mageia uses. For example on the "social" end, look where it starts:

As an example of a scenario (originally proposed by vatsa@in.ibm.com)
that can benefit from multiple hierarchies, consider a large
university server with various users - students, professors, system
tasks etc. The resource planning for this server could be along the
following lines:

If I'm wrong, then please explain it to me why I'm seeing all these unnecessary things that I will never use.

[dedanna1029]

For that matter, I would like to know what the whole tmpfs allocation, or "allocations" is/are for, what /dev/shm is, etc. - I have no clue. I need it all broken down. Are they the same partition as the cgroups one? What are they? What are they for? Is it anything I can reclaim and allocate for myself to go to other things I do need?

Edit: Never mind, it's not worth standing up for, or arguing over the open source right to know what goes on under our hood here, and I'm not going to. Please close this. I'll ask someone at kernel.org what I need to know, or somewhere else - evidently no one else knows the answers, either, here. Thanks.

[doktor5000]

evidently no one else knows the answers, either, here.

Interesting attitude - waiting not even a day after you asked ...
Good luck @ kernel.org - or somewhere else ...

[dedanna1029]

Well, you had four whole posts up there dok, and you never answered the question. You merely came on with the "you're wrong" attitude, without even attempting to actually explain anything.
I've seen this in other threads from you with people. Most don't deal with arrogance very well, without questions being answered.

Sander gave me more in that one line than you did in four posts. My attitude is that we all have a right under open source principles to know and understand what goes on under the hood of our machines. You merely went on the defensive, and that was it, when I was honestly trying to understand something. I'm not arguing with someone with that kind of attitude. You totally drowned out Sander, btw, who gave the info in a way I could understand. I just now saw his post.

I also have been using Linux (was even using Mageia for a good while before I came to this forum) for a lot of years, and do not need to be treated like an idiot with it.

[doktor5000]

Interesting attitude, when i tried to give you some explanations in my first two posts, links to further documentation and upstream bugreports.
Then you started with some weird attitude, and now i'm the one to blame. Really interesting ...