[PATCH] JDK-8176571: Fine bitmaps should be allocated as belonging to mtGC

[Milan Mimica]

Hi

>
>Some procedural points: we would need you to sign a contributor
>agreement if you are not covered yet in some way to be able to take
>your contributions.

Sure will do. If we ever come near to having an acceptable patch.

>
>It is a bit awkward to have a generic utility class to always report
>everything as belonging to GC :-)

I would argue that having everything reported as mtInternal is equally wrong.

Can I propose to move the class into G1 scope? What is the point of a utility
class not used in any other place?

>
>There is another option, having an additional field in CHeapBitmap that
>indicates from what pool the memory should be assigned to.
>From a memory POV that additional (4-byte) member should be zero-cost
>for the remembered sets due to padding (see class PerRegionTable in
>heapRegionRemSet.cpp, immediately after the CHeapBitmap there is an
>int-sized member followed by a pointer).

Sicne ArayAllocator needs a compile-time constant we don't have this option.
There is going to be at least some pulling of code into header files.

Milan Mimica, Senior Software Engineer / Division Lead