The memory2 block uses incorrect math to calculate ram usage

[koshell]

Being brief, the memory and memory2 blocks give hilariously different results.

Best I can tell the math used by the memory2 block to calculate free ram is wrong. The block uses an assumption like 'Used Memory = Total Memory - Free Memory' however Linux tries very hard to not actually leave any wasted 'free' memory floating around. Instead the correct way to calculate it would be something like:
'Actual Memory Usage = Total - (Free + Buffers + Cached)' (I got the math from https://scoutapm.com/blog/determining-free-memory-on-linux )

This is why the script (memory) says for example I am only using 30% of my ram but the C program (memory2) says I am using 99%.

[carreter]

Seems like the sysinfo system call doesn't provide info on cache memory unfortunately... so some direct parsing of /proc/meminfo would have to be done.

https://stackoverflow.com/questions/349889/how-do-you-determine-the-amount-of-linux-system-ram-in-c

[Elcoid]

Hello,
I just want to bring these two merge requests to your attention: #389 #442
Maybe one of them solves the problem.

In the meantime, I'm working on memory3, which does what @carreter suggested about parsing /proc/meminfo. I'm looking at the source code of procps and htop to find out exactly how they compute the ram usage. For now it's in its own repo, but I will make a merge request here when it's done (even though it will probably never be merged, but who knows).

Edit: Here's the merge request: #539