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

[Joachim Kern]

On Mon, 18 Dec 2023 10:25:50 GMT, Thomas Stuefe <stuefe at openjdk.org> wrote:

>> Joachim Kern has updated the pull request incrementally with two additional commits since the last revision:
>> 
>>  - trailing whitespace
>>  - Following most of Thomas proposals
>
> src/hotspot/os/aix/os_aix.cpp line 30:
> 
>> 28: #pragma alloca
>> 29: 
>> 30: 
> 
> please remove whitespace change

Done

> src/hotspot/os/aix/os_aix.cpp line 193:
> 
>> 191: // local variables
>> 192: 
>> 193: 
> 
> please remove whitespace change

Done

> 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.

> src/hotspot/os/aix/porting_aix.cpp line 1143:
> 
>> 1141:       // entry of the array to the place of the entry we want to remove and overwrite it
>> 1142:       if (i < g_handletable_used) {
>> 1143:         g_handletable[i] = g_handletable[g_handletable_used];
> 
> To be super careful, I would zero out at least the handle of the moved item like this:
> `g_handletable[g_handletable_used].handle = nullptr`

Done

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

PR Review Comment: https://git.openjdk.org/jdk/pull/16920#discussion_r1429950832
PR Review Comment: https://git.openjdk.org/jdk/pull/16920#discussion_r1429951237
PR Review Comment: https://git.openjdk.org/jdk/pull/16920#discussion_r1429946043
PR Review Comment: https://git.openjdk.org/jdk/pull/16920#discussion_r1429947950