Request for review (m) 8008966: NPG: Inefficient Metaspace counter functions cause large young GC regressions

[Jon Masamitsu]

This is the promised semantic changes for the code review.  Whereas
the original set of changes only maintained a running sum for the
capacity of all the space for metadata, this added a running sum
for the used space allocated and holding metadata.

http://cr.openjdk.java.net/~jmasa/8008966/webrev.00_2/

This is an incremental webrev based on the name change webrev
(webrev.00_1) below.  A complete webrev with all changes will
be published after comments for this have been digested.

Thanks.

Jon

On 3/29/2013 5:20 PM, Jon Masamitsu wrote:
> Ths webrev has mostly name changes suggested by the code
> review comments.  There are additional changes coming that
> relate to semantic changes suggested by the code review.
>
> This was created by deleting some of the suggested semantic
> changes so will not compile.  The next webrev will be relative
> to this one so you won't have to look at the name changes when
> looking and the semantic changes.
>
> Ignore the block comment about chunk accounting at the
> beginning of metaspace.cpp.  That will be updated or deleted
> in the next webrev.
>
> The deletion of some dead code is included in this webrev
> (limited number of lines).
>
> http://cr.openjdk.java.net/~jmasa/8008966/webrev.00_1/
>
> Thanks.
>
> Jon
>
> On 3/26/2013 9:13 PM, Jon Masamitsu wrote:
>>
>> Replace the use of a method that calculated the total capacity of
>> the Metaspaces by iterating over all the Metaspaces by maintaining
>> the sum of Metaspace capacities as the Metachunks are
>> allocated to each Metaspace.  Also maintain a sum for each
>> Metaspace as the Metachunks are allocated to that Metaspace.
>>
>> Change should_expand() and compute_new_space() to
>> calculate quantities in bytes.
>>
>> Remove calls to methods that calculated totals for
>> "used" and "free" by iterating over the Metaspaces
>> in product mode.  In some cases substitute the use
>> of capacity for used.
>>
>> http://cr.openjdk.java.net/~jmasa/8008966/webrev.00/
>>
>> Thanks.
>>
>> Jon
>