On Wed, 18 Sep 2024 00:26:24 GMT, David Holmes <[email protected]> wrote:
>> Robert Toyonaga has updated the pull request with a new target base due to a
>> merge or a rebase. The pull request now contains five commits:
>>
>> - Merge master
>> - replace tty in pd_release_memory while holding NMT lock.
>> - Switch to using a Hotspot Mutex.
>> - Comments. Hide assertion behind DEBUG. Replace MemoryFileTracker locker.
>> make reentrant.
>> - Replace ThreadCritical with a specific NMT lock
>
> src/hotspot/share/runtime/mutexLocker.hpp line 197:
>
>> 195: _mutex(mutex) {
>> 196: bool no_safepoint_check = flag == Mutex::_no_safepoint_check_flag;
>> 197: if (_mutex != nullptr && Thread::current_or_null() != nullptr) {
>
> I do not like this addition to the mutex locker code. First, it probably
> needs to be `Thread::current_or_null_safe` in case we ever lock in a
> signal-handling context. But second this slows down all mutex uses. Instead
> `NMTLocker` should extend ConditionalMutexLocker and make the current thread
> check the condition.
@dholmes-ora I agree with you, but it seems strange that MutexLockerImpl even
handles mutex==null instead of asserting that.
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PR Review Comment: https://git.openjdk.org/jdk/pull/20852#discussion_r1770438593
