RFR: 8300645: Handle julong values in logging of GET_CONTAINER_INFO macros

[Severin Gehwolf]

On Mon, 13 Feb 2023 21:12:17 GMT, Ioi Lam <iklam at openjdk.org> wrote:

>>> Why is this changed from julong to jlong?
>> 
>> Because `GET_CONTAINER_INFO` might log lines such as these (with `-Xlog:os+container=trace`):
>> 
>> Swappiness is: 18446744073709551614
>> 
>> ... on systems where for example `swapaccount=0` is being set on the kernel comandline. That is actually `-2`, i.e. `OS_CONTAINER_ERROR`. Which is just very confusing.
>> 
>> That file, `memory.swappiness`, actually contains small numbers (if it exists). So there is really no need to read this in as `julong`. With this change it would print on `swapaccount=0` systems:
>> 
>> 
>> Swappiness is: -2
>> 
>> 
>> There is really no need to read as `julong`.
>
> Is the motivation of this PR that `GET_CONTAINER_INFO` can't correctly print the error log for unsigned types?
> 
> 
>     log_trace(os, container)(logstring, (return_type) OSCONTAINER_ERROR); \
> 
> 
> If so, I think it's better to fix the logging code so that it can handle unsigned types, and not change all values to signed types. Fixing logging is a lot easier than verifying that your type casting and range clipping is correct.

Yes.

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PR: https://git.openjdk.org/jdk/pull/12166