RFR(M, v14): JDK-8059036 : Implement Diagnostic Commands for heap and finalizerinfo
Staffan Larsen
staffan.larsen at oracle.com
Fri Jun 5 12:24:33 UTC 2015
Thanks - this version looks good to me.
/Staffan
> On 5 jun 2015, at 13:00, Dmitry Samersoff <dmitry.samersoff at oracle.com> wrote:
>
> Staffan,
>
> Thank you for review!
>
> Done. Webrev updated in-place (press shift-reload).
>
> http://cr.openjdk.java.net/~dsamersoff/JDK-8059036/webrev.14
>
> -Dmitry
>
> On 2015-06-05 11:20, Staffan Larsen wrote:
>> Dmitry,
>>
>> I’d like to propose the following change to get prettier output (more in line with GC.class_histogram):
>>
>> diff --git a/src/share/vm/services/diagnosticCommand.cpp b/src/share/vm/services/diagnosticCommand.cpp
>> --- a/src/share/vm/services/diagnosticCommand.cpp
>> +++ b/src/share/vm/services/diagnosticCommand.cpp
>> @@ -341,7 +341,6 @@
>> void FinalizerInfoDCmd::execute(DCmdSource source, TRAPS) {
>> ResourceMark rm;
>>
>> - output()->print_cr("Unreachable instances awaiting finalization:");
>> Klass* k = SystemDictionary::resolve_or_null(
>> vmSymbols::finalizer_histogram_klass(), THREAD);
>> assert(k != NULL, "FinalizerHistogram class is not accessible");
>> @@ -375,12 +374,15 @@
>>
>> assert(count_res != NULL && name_res != NULL, "Unexpected layout of FinalizerHistogramEntry");
>>
>> + output()->print_cr("Unreachable instances waiting for finalization");
>> + output()->print_cr("#instances class name");
>> + output()->print_cr("-----------------------");
>> for (int i = 0; i < result_oop->length(); ++i) {
>> oop element_oop = result_oop->obj_at(i);
>> oop str_oop = element_oop->obj_field(name_fd.offset());
>> char *name = java_lang_String::as_utf8_string(str_oop);
>> int count = element_oop->int_field(count_fd.offset());
>> - output()->print_cr("Class %s - %d", name, count);
>> + output()->print_cr("%10d %s", count, name);
>> }
>> }
>>
>>
>> A couple of nits:
>>
>> diagnosticCommand.cpp:359 - extra space after =
>> diagnosticCommand.cpp:361 - spelling: finlalization -> finalization
>> FinalizerInfoTest.java:69: - spelling: intialized -> initialized
>> FinalizerInfoTest.java:71 - I’d like to see the ; on a new line
>>
>>
>> Thanks,
>> /Staffan
>>
>>
>>> On 5 jun 2015, at 00:20, Mandy Chung <mandy.chung at oracle.com> wrote:
>>>
>>>
>>>> On Jun 4, 2015, at 8:49 AM, Dmitry Samersoff <dmitry.samersoff at oracle.com> wrote:
>>>>
>>>> Mandy,
>>>>
>>>> Webrev updated in-place (press shift-reload).
>>>>
>>>> http://cr.openjdk.java.net/~dsamersoff/JDK-8059036/webrev.14
>>>>
>>>> getFinalizerHistogram() now returns Entry[]
>>>>
>>>> @library and @build removed from the test.
>>>
>>>
>>> Looks fine.
>>>
>>> Thanks
>>> Mandy
>>>
>>>>
>>>> -Dmitry
>>>>
>>>> On 2015-06-04 16:56, Mandy Chung wrote:
>>>>>
>>>>>> On Jun 4, 2015, at 6:38 AM, Dmitry Samersoff <dmitry.samersoff at oracle.com> wrote:
>>>>>>
>>>>>> Mandy,
>>>>>>
>>>>>> Thank you for the review.
>>>>>>
>>>>>> Updated webrev is:
>>>>>>
>>>>>> http://cr.openjdk.java.net/~dsamersoff/JDK-8059036/webrev.14
>>>>>>
>>>>>
>>>>> Thanks for the update and the test.
>>>>>
>>>>>> addressed comments, added a unit test to JDK workspace.
>>>>>>
>>>>>
>>>>> This test does not need @library and @build, right?
>>>>>
>>>>>>
>>>>>> On 2015-06-03 21:36, Mandy Chung wrote:
>>>>>>
>>>>>>> Should getFinalizerHistogram() return FinalizerHistogramEntry[]?
>>>>>>> The VM knows the returned type anyway.
>>>>>>
>>>>>> "[java/lang/ref/Entry" signature would need a separate symbol entry in
>>>>>> swollen vmSymbols::init() so I would prefer to stay with more generic
>>>>>> Object[]
>>>>>>
>>>>>
>>>>> You already add several symbols - why is it an issue for another one? Or if adding vm symbols is a concern, you should revert to String and int[] that you decide not to. The decision should apply consistently (use String and int, or new Java type).
>>>>>
>>>>>
>>>>>>> Perhaps the getFinalizerHistogram method should be renamed
>>>>>>> e.g. "dump"?
>>>>>>
>>>>>> The line in vmSymbols looks like:
>>>>>>
>>>>>> template(
>>>>>> get_finalizer_histogram_name, "getFinalizerHistogram")
>>>>>>
>>>>>> I would prefer to keep method name specific enough to be able to
>>>>>> find it by grep in jdk code.
>>>>>
>>>>>
>>>>> Grep in jdk code is easy as you have a new class :)
>>>>>
>>>>> Mandy
>>>>>
>>>>>>
>>>>>> (other comments are addressed)
>>>>>>
>>>>>> -Dmitry
>>>>>>
>>>>>>
>>>>>> On 2015-06-03 21:36, Mandy Chung wrote:
>>>>>>>
>>>>>>>
>>>>>>> On 06/03/2015 08:29 AM, Dmitry Samersoff wrote:
>>>>>>>> Updated webrev:
>>>>>>>>
>>>>>>>> http://cr.openjdk.java.net/~dsamersoff/JDK-8059036/webrev.13
>>>>>>>
>>>>>>> I reviewed the jdk change. The version looks okay and some comments:
>>>>>>>
>>>>>>> ReferenceQueue.java - you should eliminate the use of rawtype:
>>>>>>>
>>>>>>> 84 Reference rn = r.next;
>>>>>>>
>>>>>>> Change Reference to Reference<? extends T>
>>>>>>
>>>>>> done.
>>>>>>
>>>>>>>
>>>>>>> The forEach method - eliminate the use of raw type and
>>>>>>> move @SuppressWarning to the field variable in line 182:
>>>>>>>
>>>>>>> @SuppressWarnings("unchecked")
>>>>>>> Reference<? extends T> rn = r.next;
>>>>>>
>>>>>> done.
>>>>>>
>>>>>>>
>>>>>>> FinalizerHistogram.java
>>>>>>> Copyright year needs update.
>>>>>>
>>>>>> done.
>>>>>>>
>>>>>>> I personally think the VM code would be much simpler if you stay with
>>>>>>> alternative entry of String and int than dealing with a
>>>>>>> FinalizerHistogramEntry private class. It's okay as FinalizerHistogram
>>>>>>> class is separated.
>>>>>>>
>>>>>>> The comment in line 35 is suitable to move to the class description and
>>>>>>> this is the suggestion.
>>>>>>>
>>>>>>> // This FinalizerHistogram class is for GC.finalizer_info diagnostic
>>>>>>> command support.
>>>>>>> // It is invoked by the VM.
>>>>>>
>>>>>> done.
>>>>>>
>>>>>>>
>>>>>>> Should getFinalizerHistogram() return FinalizerHistogramEntry[]? The VM
>>>>>>> knows the returned type anyway.
>>>>>>
>>>>>> "[java/lang/ref/Entry" signature would need a separate symbol entry in
>>>>>> swollen vmSymbols::init() so I would prefer to stay with more generic
>>>>>> Object[]
>>>>>>
>>>>>>> It's an inner class of
>>>>>>> FinalizerHistogram and it can simply be named as "Entry". I suggest to
>>>>>>> have Entry::increment method to replace ".instanceCount++".
>>>>>>
>>>>>> done.
>>>>>>
>>>>>>>
>>>>>>> The tests are in hotspot/test. Can you add a unit test in jdk/test?
>>>>>>> Perhaps you can test FinalizerHistogram.getFinalizerHistogram() via
>>>>>>> reflection - just a sanity test.
>>>>>>
>>>>>> done. The test repeats hotspot one, but uses reflection instead of VM call.
>>>>>>
>>>>>>>
>>>>>>> A minor naming comment - now you have a FinalizerHistogram class.
>>>>>>> Perhaps the getFinalizerHistogram method should be renamed e.g. "dump"?
>>>>>>
>>>>>> The line in vmSymbols looks like:
>>>>>>
>>>>>> template(
>>>>>> get_finalizer_histogram_name, "getFinalizerHistogram")
>>>>>>
>>>>>> I would prefer to keep it specific enough to be able to
>>>>>> find it by grep in jdk code.
>>>>>>
>>>>>>
>>>>>> --
>>>>>> Dmitry Samersoff
>>>>>> Oracle Java development team, Saint Petersburg, Russia
>>>>>> * I would love to change the world, but they won't give me the sources.
>>>>>
>>>>
>>>>
>>>> --
>>>> Dmitry Samersoff
>>>> Oracle Java development team, Saint Petersburg, Russia
>>>> * I would love to change the world, but they won't give me the sources.
>>>
>>
>
>
> --
> Dmitry Samersoff
> Oracle Java development team, Saint Petersburg, Russia
> * I would love to change the world, but they won't give me the sources.
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