System metric container-level or host-level?

如果服务是部署在容器内，那么读取到的内存是主机的，还是相对于容器限制的内存大小的呢，如果读取到的是主机内存的话，这样看起来貌似不太适合用于容器内部的限流。

Start by locating Sentinel's system-metric collection entry points and determine whether memory values come from the host or the container's limits. Confirm the behavior in a containerized environment and document or reproduce the result before proposing a change; the issue does not name files or tests.

Written by the indexing model from the issue text.