Hello, I’ve been watching the memory and swap usage for the past few months (via cat /proc/meminfo, top and htop) MyCloud (Gen1) never, ever used the last 41-55MB of the memory for anything. Even if I pushed the device on multiple tasks it simply reduced cache and used swapspace… This doesn’t change even if I lower the vm.swappiness value. If I set it to 0, device simply won’t boot, anything else, MyCloud still won’t use that RAM.
To give a numeric example; Currently, my device has 226MB ram (not 256MB); 3MB used for buffer, 137MB used, and 33MB cache, leaving full 53MB completely untouched. If I open web browser, my used ram inceased by 3MB, cache reduced by 4MB, and My swap is also increased by 1MB… Looking deeper, 23MB of my 114MB swap usage is marked as “SwapCached”… Why??? I still have 54MB free ram at this point??? I am not even close to a very serious low memory situation that would warrant even moving cache to the swap???
This isn’t a normal behaviour for any Linux machine I know of… Normally even on my PC with 32GB ram, I can easily make Linux utilize all my 32GB as used+buffer+cache+inactive, leaving just 2-3 MB of free memory. It would take just a few minutes of opening, re-opening, closing random programs and websites. On a tiny 256MB RAM on which so many services was supposed to run, “free memory” shouldn’t even exist right after the boot.
Now, I can understand some 30MB of the 256MB ram may be reserved to be used as ramdisk or something else, but I don’t understand why the ram recognized as available (out of 226MB) is not fully used. ~41-55 MB is not a small number, its nearly 1/4th of all RAM and enabling it can -depending on usage- a) halve my swap usage, b)triple my available cache memory. c)can load my entire swapped cache. At worst, it could be used as inactive ram; like when after closing my web browser, if I reopen it, it would open instantly instead of reading everything from disk again… In all these cases, it would significantly speed up the device at exactly zero cost to anything else.
Has anyone tested/noticed this behaviour and have an explaination? Or better, a solution to make MyCloud’s Linux kernel use this RAM?
Note that I am talking about “free” ram in truest sense, not inactive, cached, or writeback RAM.