swap_limit semantics are confusing

[nipun-sehrawat]

Hello,

MemorySpec allows users to set 'swap_limit', whose value ultimately maps to memory.memsw.limit_in_bytes. This is a bit confusing as these two entities represent different things: swap_limit gives the impression that one can specify the limit of swap space available to the application, whereas memory.memsw.limit_in_bytes value is the sum of memory and swap usage.

So, if I were to create a container with 50M memory and no swap, it's config would currently look like:
memory {
limit: 50M
swap: 50M
}

whereas, the following captures the intent better:
memory {
limit: 50M
swap: 0
}

What do folks think? I can make the required change, if this change in semantics is acceptable to the authors. We can deprecate the proto field and introduce a new one that specifies just the swap limit.

Thanks,
Nipun