RFR: 8287107: CgroupSubsystemFactory.setCgroupV2Path asserts with freezer controller [v2]

[Ioi Lam]

On Tue, 24 May 2022 10:12:31 GMT, Severin Gehwolf <sgehwolf at openjdk.org> wrote:

>> Ioi Lam has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   @jerboaa comments
>
> src/java.base/linux/classes/jdk/internal/platform/CgroupSubsystemFactory.java line 155:
> 
>> 153:                 // There are some controllers (such as freezer) that Java doesn't
>> 154:                 // care about. Just ignore them. These are not considered in the
>> 155:                 // anyCgroupsV1Controller/anyCgroupsV1Controller checks.
> 
> It's not clear why this `default` is necessary. Could we just add the comment like so:
> 
> 
> // Intentional fall-through. There are controllers (such as freezer) that
> // Java doesn't care about. Just ignore them. Only listed controllers are
> // considered in the anyCgroupsV1Controller/anyCgroupsV2Controller checks.

This is not a fall-through because the previous line ends with a `break`.

> src/java.base/linux/classes/jdk/internal/platform/CgroupSubsystemFactory.java line 229:
> 
>> 227:         String name = tokens[1];
>> 228:         if (!name.equals("")) {
>> 229:             // This is probably a v1 controller that we have ignored (e.g., freezer)
> 
> Could we add an assertion that the controller isn't in the `infos` map?
> 
>            if (!name.equals("")) {
>             // This must be a v1 controller that we have ignored (e.g., freezer)
>             assert infos.get(name) == null;
>             return;
>          }

Fixed.

-------------

PR: https://git.openjdk.java.net/jdk/pull/8858