Review request: 8025059: Metspace::should_expand mixes bytes and words in check against MaxMetaspaceSize

[Stefan Karlsson]

On 9/19/13 5:22 PM, Coleen Phillimore wrote:
>
> Yes, I'm confused why you're fixing this now and not with the change 
> that really fixes it to be consistent.  Does it enable more tests to run?

The main reason is that I'm not the only one working on JDK-8024547, and 
pushing some of my patches out to the hotspot-gc will make it easier for 
the others to help out with some of the listed issues.

StefanK

> Thanks,
> Coleen
>
> On 09/19/2013 11:10 AM, Bengt Rutisson wrote:
>>
>> Hi Stefan,
>>
>> Given that we just want to get the byte/word conversion right I think 
>> this change is fine. The bug JDK-8024547 contains a long list of 
>> improvements so it is a bit difficult to tell, but the asymmetry with 
>> using reserved memory for NonClassType and allocated memory for 
>> ClassType will go away with some of the changes for JDK-8024547, right?
>>
>> 1345     size_t nonclass_allocated = 
>> MetaspaceAux::reserved_bytes(Metaspace::NonClassType);
>> 1346     size_t class_allocated    = 
>> MetaspaceAux::allocated_capacity_bytes(Metaspace::ClassType);
>> 1347     size_t real_allocated     = nonclass_allocated + 
>> real_allocated;
>>
>> Thanks,
>> Bengt
>>
>>
>> On 9/19/13 4:59 PM, Stefan Karlsson wrote:
>>> http://cr.openjdk.java.net/~stefank/8025059/webrev.00/
>>> https://bugs.openjdk.java.net/browse/JDK-8025059
>>>
>>> The following code in Metaspace::should_expand:
>>>
>>> if (!FLAG_IS_DEFAULT(MaxMetaspaceSize)) {
>>>   size_t real_allocated = Metaspace::space_list()->reserved_words() +
>>> MetaspaceAux::allocated_capacity_bytes(Metaspace::ClassType);
>>>   if (real_allocated >= MaxMetaspaceSize) {
>>>     return false;
>>>   }
>>>
>>> doesn't convert Metaspace::space_list()->reserved_words() to bytes, 
>>> as it should.
>>>
>>> Note that when JDK-8024547 gets fixed, this check will be rewritten 
>>> to limit the amount of committed memory in both the Class and 
>>> NonClass metaspaces. See:
>>> https://bugs.openjdk.java.net/browse/JDK-8024547: MaxMetaspaceSize 
>>> should limit the committed memory used by the metaspaces
>>>
>>> Testing: I've run our internal testing that sets the MaxMetaspaceSize.
>>>
>>> thanks,
>>> StefanK
>>
>