Current heap layout of generational mark-sweep GC

[Neo Jia]

On 5/14/07, Jon Masamitsu <Jon.Masamitsu at sun.com> wrote:
> Neo,
>
> If by "generational mark-sweep GC" you mean the UseSerialGC
> or UseParNewGC,

I mean the UseSerialGC.

 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.

The current "PrintMallocFree" seems broken already. Do you still use
this to check the
CHeap usage?

Thanks,
Neo

>
> 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
> >>
> >>
> >
> >
>


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