RFR (L) 8061205: MetadataOnStackMark only needs to walk code cache during class redefinition

[serguei.spitsyn at oracle.com]

Coleen,


It looks good, just one minor comment is below.

src/share/vm/code/nmethod.cpp

1628   bool a_class_was_redefined = JvmtiExport::has_redefined_a_class();
1629   if (a_class_was_redefined) {
. . .
1634   }

1757   bool a_class_was_redefined = JvmtiExport::has_redefined_a_class();
1758   if (a_class_was_redefined) {
. . .
1763   }

   Minor: No reason to keep the local variable "a_class_was_redefined"


Thanks,
Serguei


On 3/9/15 1:57 PM, Coleen Phillimore wrote:
> Summary: Only do full metadata walk during class redefinition and only 
> walk handles during class unloading.
>
> This change decouples metadata walking for redefinition and class 
> unloading, so that class unloading for G1 doesn't walk the code 
> cache.  It also decouples GC and on_stack marking in the code cache.
>
> open webrev at http://cr.openjdk.java.net/~coleenp/8061205/
> bug link https://bugs.openjdk.java.net/browse/JDK-8061205
>
> Tested with FMW performance runs. vm.quick.testlist, 
> jdk/test/java/lang/instrument tests and JPRT.
>
> Thanks,
> Coleen