RFR(S) 8038405: Clean up some virtual fucntions in Space class hierarchy

[Jon Masamitsu]

On 3/27/2014 8:18 AM, Mikael Gerdin wrote:
> Hi,
>
> On Wednesday 26 March 2014 17.22.03 Mikael Gerdin wrote:
>> Hi,
>>
>> I'm doing some cleanups in the "Space" classes to simplify the code for the
>> G1 class unloading work[1].
>> This change moves around some virtual functions in Space to more (in my
>> mind) sane places:
>>
>> * Space::is_in is implemented the same by all Space subclasses, move it to
>> Space and make it non-virtual.
>> * Space::used_region has a bogus implementation that is never useful, remove
>> it.

Minor point but used_region() did do as the comment says.   It just
most often returned a region that include more than just the allocated
objects, and not a proper subregion.   Could you change the comment to

  136   // Returns a subregion of the space containingonlytheallocatedobjects in
  137   // the space.

if that is how it is used in all the other spaces.

Rest looks good.

Reviewed.

Jon

>> * Consolidate more code related to saved_marks in the Space base class
> When making set_saved_mark non-virtual G1OffsetTableContigSpace's override of
> set_saved_mark became a shadowing function instead. The code still works fine
> since all calls to G1OffsetTableContigSpace::set_saved_mark are on pointers to
> HeapRegion and not the base class.
>
> To clarify that G1 uses the "saved_mark" functionality for a completely
> different purpose I have renamed the G1 function to record_top_and_timestamp:
>
> Incremental webrev: http://cr.openjdk.java.net/~mgerdin/8038405/webrev.0.to.1
> Webrev: http://cr.openjdk.java.net/~mgerdin/8038405/webrev.1
>
> /Mikael
>
>> * Make CompactibleSpace::reset_after_compaction a pure virtual.
>> * Give Space::minimum_free_block_size a default implementation since only
>> CMS needs to override it.
>>
>> Bug: https://bugs.openjdk.java.net/browse/JDK-8038405
>> Webrev: http://cr.openjdk.java.net/~mgerdin/8038405/webrev.0
>>
>> /Mikael
>>
>> [1] http://openjdk.java.net/jeps/156

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