Current heap layout of generational mark-sweep GC

[Jon Masamitsu]

Neo,

If by "generational mark-sweep GC" you mean the UseSerialGC
or UseParNewGC, yes the storage you listed are the major
pieces that we allocate in the CHeap.   There are many smaller
data structures that are allocated out of the CHeap.  For example,
performance counters are CHeap allocated.  Or just the storage
for various subclasses of Generation that the GC uses.

I believe the largest piece of the CHeap that the compilers
use is the CodeCache and it is allocated before the Java
heap is allocated.

Jon

Neo Jia wrote:

> On 5/14/07, Jon Masamitsu <Jon.Masamitsu at sun.com> wrote:
>
>> Neo,
>>
>> Are you asking specifically about CHeap usage by the
>> garbage collector (i.e., you're not interested in the
>> compiler's use CHeap space)?
>
>
> Jon,
>
> Although my question is about the CHeap usage by GC, I am also interested
> in knowing the CHeap space usage of compiler.
>
> Thanks,
> Neo
>
>>
>> Jon
>>
>>
>> Neo Jia wrote:
>>
>> > hi,
>> >
>> > I am wondering that for the generational mark-sweep GC, if the block
>> > offset shared array is the last allocated object on the CHeap.
>> >
>> > The following is my understanding of the current heap layout:
>> >
>> > 1. The nursery space is on the lowest address
>> > 2. The mature space is following the nursery address.
>> > 3. The permanent space is following the nursery address at a higher
>> > address.
>> > 4. The card table is allocated from the end of the permanent space,
>> > the regions inside it will be mapped to these previous three spaces
>> > sequentially, from lower address to higher address.
>> > 5. The block offset shared array used by the mature space will be
>> > allocated at the end of the card table area, which is used by mature
>> > space. And the virtual space size of this area will be set according
>> > to the mature space and word bits.
>> >
>> > So, is there any space allocated following?
>> >
>> > Thanks,
>> > Neo
>>
>>
>
>