RFR: 8252041: G1: Fix incorrect uses of HeapRegionManager::max_length [v3]

[Thomas Schatzl]

Hi Stefan,

On 17.09.20 09:00, Stefan Johansson wrote:
> On Wed, 16 Sep 2020 14:59:44 GMT, Thomas Schatzl <tschatzl at openjdk.org> wrote:
> 
>>> Hi all,
>>>
>>>    can I have reviews for this change that fixes some uses of HeapRegionManager::max_regions()/max_expandable_regions() in
>>>    our code to use the correct variant?
>>>
>>> HeapRegionManager::max_length gives the absolute maximum number of regions reserved for the heap based on the
>>> reservation.
>>> HeapRegionmanager::max_expandable_regions() returns the maximum number of regions the heap can grow to (can be
>>> committed).
>>> Typically they are exchangeable, but if the reservation is larger than what -Xmx allows (like when file-mapping old
>>> gen), this is not the case, and causes assertions. In some cases the existing region manager code could (if it reserved
>>> more than -Xmx) give back more than -Xmx allows.  Testing: tier1-5.
>>
[...]

> 
> Looks good apart from two comments which still uses the max-prefix for `reserved_length()`.
> 

Fixed and thanks for your review.

Thomas