RFR(S): 8159056: [aix] Compressed class space not allocated in lower regions

[David Holmes]

Hi Goetz,

I will sponsor this but need an Aarch64 reviewer to confirm  the 
behaviour there is unchanged. If 4G is the first value that should 
succeed I'm not sure what the impact of trying and failing at 1G, 2G and 
3G are.

More below.

On 9/06/2016 12:21 AM, Lindenmaier, Goetz wrote:
> Hi,
>
> On AIX, test CompressedClassPointers.java fails. This is because allocate_metaspace_compressed_klass_ptrs()
> tries only a single fixed address, which fails on aix.  This change uses the loop
> implemented for aarch to search for a possible location.
> The change does not affect any other platform. I had to edit the aarch code, but
> it's supposed to behave as before.
>
> Please review this change. I please need a sponsor.
> http://cr.openjdk.java.net/~goetz/wr16/8159056-aix_CCSTest/webrev.01/

2958     // the base, 4G alignemnt is helpful, too.

Typo: alignment

2959     size_t incrememnt = AARCH64_ONLY(4*)G;

Typos: increment

2963       if (a == (char *)(32*G)) { incrememnt = 4*G; } // Go faster 
from here on. Zero-based is no more possible.

Please split into multiple lines. "no more possible" is not correct 
grammar in this context suggest "no longer possible".

Thanks,
David

> Best regards,
>   Goetz.
>