RFR: 8292083: Detected container memory limit may exceed physical machine memory [v19]

[Thomas Stuefe]

On Thu, 25 Aug 2022 17:06:37 GMT, Severin Gehwolf <sgehwolf at openjdk.org> wrote:

> The gist of this patch is code like this:
> 
> ```
> jlong CgroupV1Subsystem::read_memory_limit_in_bytes() {
>   GET_CONTAINER_INFO(julong, _memory->controller(), "/memory.limit_in_bytes",
>                      "Memory Limit is: " JULONG_FORMAT, JULONG_FORMAT, memlimit);
>   if (memlimit >= _unlimited_memory) {
>    ...
>   } else {
>     return (jlong)memlimit;
>   }
> ```
> 
> ... might return arbitrary large values on some systems (note that `_unlimited_memory = (LONG_MAX / os::vm_page_size()) * os::vm_page_size()` which can be fairly large; we've observed systems where the cgroup interface files have `92233720365056` whereas the `_unlimited_memory` value was `9223372036854771712`). That on a system with 8GB physical memory.
> 

Okay, makes sense to fix it. But why not return "invalid" or "not set" and give the caller the responsibility to deal with it?

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PR: https://git.openjdk.org/jdk/pull/9880