RFR: 8322853: Should use ConditionalMutexLocker in NativeHeapTrimmerThread::print_state

[David Holmes]

On Tue, 2 Jan 2024 16:04:30 GMT, Denghui Dong <ddong at openjdk.org> wrote:

> Hi all,
> 
> Please help review this small fix.
> 
> MutexLocker requires that mutex != nullptr, so we should use ConditionalMutexLocker instead.
> 
> Also, this patch made '_stop' volatile, since it will be read twice in run() but may be changed.

ConditionalMutexLocker change is fine

> Also, this patch made '_stop' volatile, since it will be read twice in run() but may be changed.

The only way it can be changed is if a `wait` is done which releases and reacquires the mutex, and the variable is only set while holding the mutex, so reading it twice in run is perfectly safe without it being volatile.

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Marked as reviewed by dholmes (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/17226#pullrequestreview-1801282374