[RFR] 8061715: gc/g1/TestShrinkAuxiliaryData15.java fails with java.lang.RuntimeException: heap decommit failed - after > before

[Andrey Zakharov]

Hi, team

Last one webrev.07 was with sad mistake - not removed ToNativeFromVM call.
here is fixed

webrev:
http://cr.openjdk.java.net/~azakharov/8061715/webrev.08/

hs-gc same:
http://cr.openjdk.java.net/~azakharov/8061715/webrev.06/hs-gc/

testing: ok on STH queue  2015-03-13-103151.gtee.auxdata

Thanks.

12.03.2015 19:46, Andrey Zakharov пишет:
> Fixed
> webrev: http://cr.openjdk.java.net/~azakharov/8061715/webrev.07/
>
> hs-gc is same:
> http://cr.openjdk.java.net/~azakharov/8061715/webrev.06/hs-gc/
>
> Testing on the run: STH queue - 2015-03-12-160604.gtee.auxdata
>
> Thanks.
>
> 12.03.2015 16:16, Andrey Zakharov пишет:
>> The following code is not correct with regards to the safepoint 
>> protocol. You should not perform the ToNativeFromVM transition until 
>> you have received the data from the VM. After the transition a GC 
>> pause may occur while you are executing in 
>> get_auxillary_data_memory_usage and you can get strange results.

>>>
>>>  328 WB_ENTRY(jobject, WB_G1AuxiliaryMemoryUsage(JNIEnv* env))
>>>  329   ResourceMark rm(THREAD);
>>>  330   ThreadToNativeFromVM ttn(thread);
>>>  331   G1CollectedHeap* g1h = G1CollectedHeap::heap();
>>>  332   MemoryUsage mu = g1h->get_auxiliary_data_memory_usage();
>>>  333
>>>  334   jclass jclass_memory_usage = 
>>> env->FindClass("java/lang/management/MemoryUsage");
>>>  335   CHECK_JNI_EXCEPTION_(env, NULL);
>>>  336   if (jclass_memory_usage == NULL) {
>>>
>>> I just found out that there is an existing function which creates a 
>>> java.lang.management.MemoryUsage from a C++ MemoryUsage object,
>>> MemoryService::create_MemoryUsage_obj(MemoryUsage usage, TRAPS)
>>>
>>> Using this you can get rid of the state transition altogether and do 
>>> something like:
>>>
>>> WB_ENTRY(jobject, WB_G1AuxiliaryMemoryUsage(JNIEnv* env))
>>>   G1CollectedHeap* g1h = G1CollectedHeap::heap();
>>>   MemoryUsage mu = g1h->get_auxiliary_data_memory_usage();
>>>   Handle h = MemoryService::create_MemoryUsage_obj(usage, CHECK_NULL);
>>>   return JNIHandles::make_local(env, h());
>>> WB_END
>>>
>>> This code is almost the same as jmm_GetMemoryPoolUsage in 
>>> management.cpp so if it doesn't compile see if I've missed something.
>>> I'm pretty sure you don't need a ResourceMark for this function 
>>> since it does not allocate any memory in the resource area.
>>>
>>> /Mikael
>>
>> Hi, Mikael. Thanks for the tip. It makes things better here. But I'm 
>> in doubt about needless of ResourceMark. It exists in mentioned 
>> *jmm_GetMemoryPoolUsage:
>>
>> *JVM_ENTRY(jobject, jmm_GetMemoryPoolUsage(JNIEnv* env, jobject obj))
>> *  ResourceMark rm(THREAD);*
>>
>>   MemoryPool* pool = get_memory_pool_from_jobject(obj, CHECK_NULL);
>>   if (pool != NULL) {
>>     MemoryUsage usage = pool->get_memory_usage();
>>     Handle h = MemoryService::create_MemoryUsage_obj(usage, CHECK_NULL);
>>     return JNIHandles::make_local(env, h());
>>   } else {
>>     return NULL;
>>   }
>> JVM_END*
>>
>> *
>

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