On Fri, 24 Jan 2020 08:00:58 GMT, Jan Panteltje 
declaimed the following:

>
>
>kernel claims all memory space as cache,  that leaves virtually nothing (here
only 71.6 MB) for programs
>those programs then start swapping!
>
 While the OS has claimed 3.4GB as cache, note the line below reports
3.3GB as available -- meaning the OS can release that much of the cache for
use by applications. After all, the R-Pi doesn't have 6.7+GB of memory.

>
>BAD BAD BAD
>Linux error!!!!
>
>Big thread about it here with possible solutions:
>
https://unix.stackexchange.com/questions/253816/restrict-size-of-buffer-cache-i
n-linux
>

 Note that the first entry on that link complains about how long it
takes for the cache to be freed, thereby delaying the startup of fresh
applications. It does not implicate a situation with page swapping starting
up. The first "answer" refers to /file system buffers/ -- eg; output that
has not yet been forced to the file system (SD card); and with a journaling
file system, file system updates take multiple stages (things like:
allocate fresh blocks and write data; write journal log indicating where
the new data is; later update file system so log contents are now active --
read journal/write primary file system, remove relevant journal log
information).

 I really doubt that the cache usage part of the kernel has been changed
recently in a way that it does not free pages when new applications are
started.

 In your original process list, you show FOURTEEN rxvt (X-Window
terminal) processes, along with SSH and ONE xterm. My suspicion is that
something you are doing is invoking terminals, but never closing them.
Surely you aren't really running 14+ terminals at once! Each terminal
likely having a few pages dedicated to the "screen contents" of the
terminal (the main code is no doubt shared, or you'd have even more memory
tagged "used").



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 Wulfraed                 Dennis Lee Bieber         AF6VN
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