On 4/1/13 1:09 PM, Coleen Phillimore wrote:

Hi Serguei,

Sorry for the delay in reviewing this.

In instanceKlass.cpp line 2730, can you make that mtClass since it's part of class metadata?

Fixed.
Thank you for the catch!

In methodHandles.cpp, I think the whole member name table mechanism could be protected by #if INCLUDE_JVMTI since it's not needed unless you have jvmti built in the vm. And you don't need to call add_method_handle() or just have it do JVMTI_RETURN or something for the minimal vm.

My understanding was that John is considering to use the
MemberNameTable in the future for the compilation purposes.
However, I can temporarily place it under #if INCLUDE_JVMTI
until the compiler team decides what to do with it.


Also, I think you should consider a global table rather than one per class. I think we discussed this and may have decided that speed of adding these is important, but depending on how many are actually used per class, there's one pointer per class.

I thought we've reached a consensus and decided to add MNT pointer
per class as it is performance sensitive for indy calls.
Anyway, before changing it to a hashtable I'd want to hear from John and Christian first.

Maybe they could be organized as a hashtable instead like the method handle intrinsics?

The code itself looks good everywhere, except for the concern about footprint.

I very appreciate you found a time to review it!
There are not many people having an expertize in this area.


Thanks,
Serguei


Thanks,
Coleen

Can you make this mtClass on line
On 03/26/2013 04:37 AM, serguei.spit...@oracle.com wrote:

Please, review the following fix.
The fix was preliminarily reviewed by Coleen, Christian
and John but still a final and open jdk review is needed.
So that, everyone is welcome to review the fix!

This is open webrev:
http://cr.openjdk.java.net/~sspitsyn/webrevs/2013/hotspot/8008511-JVMTI-JSR292.1/

The CR is:
http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=8008511
https://jbs.oracle.com/bugs/browse/JDK-8008511


The problem is that the old version of the bootstrap method is re-invoked
after a popframe from the bootstrap method execution.
It is because the MemberName keeps a stale reference to the old method version.

The solution (suggested by John Rose) is to lazily create and keep up-to-date a MemberNameTable
which plays a role of MemberName cache assosiated with the InstanceKlass.
Then, at the Class redefinition, this cache is used to replace the old method
references in the MemberName's with the new method references.

The MemberNameTable is based on the GrowableArray<jweek>.
A C_HEAP array is allocated at the first call to InstanceKlass::add_member_name().
It is released in the InstanceKlass::release_C_heap_structures().

A global week reference to member name oop is stored in the MemberNameTable.
It allowed to avoid having the oops_do() in the MemberNameTable.
Also, the MemberNameTable won't hold member name oops in memory.

The MemberNameTable_lock mutex is added to serialize MemberNameTable's updates.

The following No_Safepoint_Verifier has been disabled:
*  src/share/vm/prims/methodHandles.cpp*:
    799 int MethodHandles::find_MemberNames(Klass* k,
    . . .
    803 DEBUG_ONLY(No_Safepoint_Verifier nsv);
    It is probably Ok, but, please, let me know if it is not.
    The assert related to locking is fired if it is not disabled.

Test coverage: vm.mlvm, nsk.jvmti, nsk.jdi tests on multiple platforms (32 vs 64-bit too).
The testing looks good so far.


Thanks,
Serguei




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