RFR: JDK-8320890: [AIX] Find a better way to mimic dl handle equality [v5]

[Thomas Stuefe]

On Mon, 18 Dec 2023 11:12:23 GMT, Joachim Kern <jkern at openjdk.org> wrote:

>> src/hotspot/os/aix/porting_aix.cpp line 1097:
>> 
>>> 1095:   }
>>> 1096: 
>>> 1097:   pthread_mutex_lock(&g_handletable_mutex);
>> 
>> You can make your life a lot easier by defining an RAII object at the start of the file:
>> 
>> struct TableLocker {
>>   TableLocker() { pthread_mutex_lock(&g_handletable_mutex); }
>>   ~TableLocker() { pthread_mutex_unlock(&g_handletable_mutex); }
>> };
>> 
>> and just place this at the beginning of your two functions
>> 
>> TableLocker lock:
>> ...
>> 
>> 
>> no need to manually unlock then, with the danger of missing a return.
>
> Great, thank you. This was one of the things I thought about, but was not sure, because I did not fully understood the MutexLocker class and the difference between Monitor and Mutex.

In hindsight, pthread mutex is the better choice anyway: it avoids dependencies to the VM lifecycle (VM mutexes are only available after VM initialization, so we could not call dlopen() before that).

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PR Review Comment: https://git.openjdk.org/jdk/pull/16920#discussion_r1430380082