Request for review (XL) 6990754: Use native memory and reference counting to implement SymbolTable

[Volker Simonis]

Hi Coleen,

I just want to ask for a little favor regarding this change. As it
touches MANY files, it would be really nice if you and other hotspot
committers could arrange their commits in a way to get as few merge
change-sets as possible around this change and if the merge
change-sets are unavoidable they should preferably be empty. As you
probably all know, this can be easily achieved with various Mercurial
extensions like 'Rebase', 'Transplant' or 'Mercurial Queues (MQ)'

This would greatly simplify the process of integration this change
into other code bases.

Thank you,
Volker

PS: of course this little wish generally applies to all changesets
because a 'linear' (or 'serialized') repository is much easier to
handle:)

On Fri, Nov 5, 2010 at 1:43 AM, Coleen Phillimore
<coleen.phillimore at oracle.com> wrote:
>
> One of the ongoing projects in Hotspot is to move the VM internal data
> structures (known as metadata) out of the Java heap (permgen) into native
> memory.  This patch is the first step in the greater project.  For more
> information please read the information in the bugs:
>
> 6964458: Reimplement class meta-data storage to use native memory
> http://bugs.sun.com/view_bug.do?bug_id=6964468
>
> 6990754: Use native memory and reference counting to implement SymbolTable
> http://bugs.sun.com/view_bug.do?bug_id=6990754
>
> I've had 3 detailed code reviews and contribution from internal team members
> never, acorn, jmasa and apangin.  If you are part of the openjdk java vm
> community we especially want to hear your comments and review.  This is a
> very large change.
>
> The major changes are in the symbolTable.hpp and symbol.hpp.  These files
> should be read FIRST.  symbolOop has been replaced with Symbol* in many of
> the source files.  Symbol* is now a reference counted type contained in the
> SymbolTable.  Symbol* is no longer an oop and it is not in the Java heap.
>  The symbolHandle uses are no longer applicable.
>
> Webrev:
> http://cr.openjdk.java.net/~coleenp/6990754_3/
>
> You can either send your comments to me directly or the whole email list.  I
> am not going to be working Friday or this weekend but will carefully address
> all comments next week.
>
> Thanks,
> Coleen
>