[crac] RFR: Prevent concurrent cleanup by cleaner thread and checkpoint notifications

[Anton Kozlov]

On Thu, 25 May 2023 06:56:51 GMT, Radim Vansa <duke at openjdk.org> wrote:

>> src/java.base/share/classes/jdk/internal/ref/CleanerImpl.java line 182:
>> 
>>> 180:         // completed by the cleaner.
>>> 181:         blockForCheckpoint = true;
>>> 182:         thread.interrupt();
>> 
>> Why it has to be interrupt and not notify(), for example?
>
> The interrupt wakes up cleaner in `queue.remove()` (line 161) in case it's blocking for next task.

OK, thanks. But what if the interrupt arrives to the thread during a cleaning while that runs, it may interrupt the cleaning, right?

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PR Review Comment: https://git.openjdk.org/crac/pull/73#discussion_r1210523210