PING: RFR: JDK-8151815: Could not parse core image with JSnap.

[Yasumasa Suenaga]

Hi Dmitry,

Thank you for your comment.
I uploaded new webrev. Could you review again?

   http://cr.openjdk.java.net/~ysuenaga/JDK-8151815/webrev.02/


Thanks,

Yasumasa


On 2016/04/13 21:41, Dmitry Samersoff wrote:
> Yasumasa,
>
> Yes. It's better.
>
> Please place all _saved_* declarations together and add a comment
> explaining what is the purpose of this variables.
>
> -Dmitry
>
>
> On 2016-04-13 15:20, Yasumasa Suenaga wrote:
>> Hi all,
>>
>> Could you review and sponsor it?
>>
>>>     http://cr.openjdk.java.net/~ysuenaga/JDK-8151815/webrev.01/
>>
>> If it is not accepted, I think that we can add new field to PerfMemory
>> for using in JSnap:
>> -----------------------
>> diff -r 4823056a5bbd src/share/vm/runtime/perfMemory.cpp
>> --- a/src/share/vm/runtime/perfMemory.cpp    Tue Apr 12 09:08:48 2016 +0000
>> +++ b/src/share/vm/runtime/perfMemory.cpp    Wed Apr 13 14:18:15 2016 +0900
>> @@ -45,11 +45,16 @@
>>                                               UINT_CHARS + 1;
>>
>>   char*                    PerfMemory::_start = NULL;
>> +char*                    PerfMemory::_saved_start = NULL;
>>   char*                    PerfMemory::_end = NULL;
>> +char*                    PerfMemory::_saved_end = NULL;
>>   char*                    PerfMemory::_top = NULL;
>> +char*                    PerfMemory::_saved_top = NULL;
>>   size_t                   PerfMemory::_capacity = 0;
>> +size_t                   PerfMemory::_saved_capacity = 0;
>>   jint                     PerfMemory::_initialized = false;
>>   PerfDataPrologue*        PerfMemory::_prologue = NULL;
>> +PerfDataPrologue*        PerfMemory::_saved_prologue = NULL;
>>
>>   void perfMemory_init() {
>>
>> @@ -103,6 +108,8 @@
>>
>>     // allocate PerfData memory region
>>     create_memory_region(capacity);
>> +  _saved_start = _start;
>> +  _saved_capacity = _capacity;
>>
>>     if (_start == NULL) {
>>
>> @@ -132,8 +139,11 @@
>>       }
>>
>>       _prologue = (PerfDataPrologue *)_start;
>> +    _saved_prologue = _prologue;
>>       _end = _start + _capacity;
>> +    _saved_end = _end;
>>       _top = _start + sizeof(PerfDataPrologue);
>> +    _saved_top = _top;
>>     }
>>
>>     assert(_prologue != NULL, "prologue pointer must be initialized");
>> -----------------------
>>
>> If it is better, I will upload a webrev.
>>
>>
>> Thanks,
>>
>> Yasumasa
>>
>>
>> On 2016/04/06 12:42, Yasumasa Suenaga wrote:
>>> Hi Dmitry,
>>>
>>> Thanks for your comment.
>>>
>>> I uploaded a new webrev. Could you review again?
>>>     http://cr.openjdk.java.net/~ysuenaga/JDK-8151815/webrev.01/
>>>
>>> On 2016/04/06 0:31, Dmitry Samersoff wrote:
>>>> Yasumasa,
>>>>
>>>> 1. It's better to change JSnap code to produce meaningful error message
>>>> instead of NPE.
>>>
>>> I added null check and set message to PerfMemory.java .
>>>
>>>
>>>> 2. We should check that no other consumer of perf counters rely on the
>>>> fact it's NULL after call to destroy(). I'm not sure that this part of
>>>> the fix is not dangerous.
>>>
>>> I added new flag (_destroyed) in PerfMemory class.
>>> This flag set true at PerfMemory::destroy().
>>>
>>> _start, _end, and more field which I removed from destroy() are
>>> private member of
>>> PerfMemory. I implemented that the getter functions of them check
>>> _destroyed flag,
>>> and returns same value before this change.
>>>
>>> So I think this change does not affect other place.
>>>
>>>
>>> Thanks,
>>>
>>> Yasumasa
>>>
>>>
>>>> -Dmitry
>>>>
>>>> On 2016-03-29 15:02, Yasumasa Suenaga wrote:
>>>>> PING: Could you review it?
>>>>>
>>>>>
>>>>> Yasumasa
>>>>>
>>>>>
>>>>> On 2016/03/22 21:24, Yasumasa Suenaga wrote:
>>>>>> PING: Could you review it?
>>>>>>
>>>>>> Yasumasa
>>>>>>
>>>>>> 2016/03/14 23:39 "Yasumasa Suenaga" <yasuenag at gmail.com
>>>>>> <mailto:yasuenag at gmail.com>>:
>>>>>>
>>>>>>       Hi all,
>>>>>>
>>>>>>       When I use `jhsdb jsnap` to get PerfCounter from core images, I
>>>>>> encountered NPE:
>>>>>>       -------------
>>>>>>       Exception in thread "main" java.lang.NullPointerException
>>>>>>                at sun.jvm.hotspot.tools.JSnap.run(JSnap.java:45)
>>>>>>                at
>>>>>> sun.jvm.hotspot.tools.Tool.startInternal(Tool.java:260)
>>>>>>                at sun.jvm.hotspot.tools.Tool.start(Tool.java:223)
>>>>>>                at sun.jvm.hotspot.tools.Tool.execute(Tool.java:118)
>>>>>>                at sun.jvm.hotspot.tools.JSnap.main(JSnap.java:67)
>>>>>>                at
>>>>>> sun.jvm.hotspot.SALauncher.runJSNAP(SALauncher.java:352)
>>>>>>                at sun.jvm.hotspot.SALauncher.main(SALauncher.java:404)
>>>>>>       -------------
>>>>>>
>>>>>>       PerfMemory::destroy() clears all members which are used in JSnap.
>>>>>>       Thus NPE is occurred.
>>>>>>
>>>>>>       I uploaded webrev for this issue.
>>>>>>       Could you review it?
>>>>>>
>>>>>>       http://cr.openjdk.java.net/~ysuenaga/JDK-8151815/webrev.00/
>>>>>>
>>>>>>       I cannot access JPRT.
>>>>>>       So I need a Sponsor.
>>>>>>
>>>>>>
>>>>>>       Thanks,
>>>>>>
>>>>>>       Yasumasa
>>>>>>
>>>>
>>>>
>
>