RFR: 8135253: Add push method to CollectionSetChooser

[Mikael Gerdin]

Hi Erik,

On 2015-09-09 13:50, Erik Helin wrote:
> Hi all,
>
> this patch adds a new `push` method to CollectionSetChooser so that
> regions can be put back at the front of the list. I've split the
> patches into three parts to ease reviewing, but I intend to push this as
> one commit. While adding the method I also renamed two variables and one
> method to make it easier to understand that the CollectionSetChooser
> essentially is a stack.
>
> Part 0: Rename _curr_index to _front and _length to _end:
> http://cr.openjdk.java.net/~ehelin/8135253/webrev.00-0/
>
> Part 1: Rename remove_and_move_to_next() to pop()
> http://cr.openjdk.java.net/~ehelin/8135253/webrev.00-1/

Given
HeapRegion* hr = regions_at(_front);
the assert
assert(regions_at(_front) == hr, "pre-condition");
can probably be removed

We ususally don't cast unused return values to void.
(void) cset_chooser->pop(); // already have region via peek()


>
> Part 2: Add the push() method
> http://cr.openjdk.java.net/~ehelin/8135253/webrev.00-2/

pop does _front += 1, the following seems needlessly verbose:

  165   _front = _front - 1;


/Mikael

>
> Enhancement:
> https://bugs.openjdk.java.net/browse/JDK-8135253
>
> Testing:
> JPRT
>
> Thanks,
> Erik
>