Container memory usage

[petervo]

Docker includes cache in it's memory.usage_in_bytes numbers so our graphs can can continue to grow making it look like there is a memory leak when there isn't. Should we subtract the cache from the total numbers? Or should we add a visual representation to clarify what is cache and available to be reclaimed by the system and what is actually in use by the process.

[petervo]

Reference issues.

moby/moby#10824
docker-archive/libcontainer#518

[dperpeet]

I think adding a visual representation to clarify the distinction would be good, but in any case the amount of memory used without caching is more important.
Why I don't think we should hide cache info completely: That might suggest that docker isn't using memory, even when it is.

[larskarlitski]

This might still be useful, even though it's an old bug.

@garrett, what do we do on the system page? Do we show cache separately?

[garrett]

Yes! As of #10282 (2018-10-31), Cockpit:

1. Doesn't show cache on the overview
2. Shows cache separately on the details graph, with optimized colors and placement, as to not emphasize cache

Details @ https://cockpit-project.org/blog/cockpit-181.html

I think the new(ish) visualization of RAM helps address this issue (and others), so I'm closing it.

Please reopen if you think I'm wrong. 😉