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

[Bengt Rutisson]

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