RFR (S): 8035815 Cache-align and pad the fast card cache

[Thomas Schatzl]

Hi Stefan,

On Tue, 2014-03-04 at 08:25 +0100, Stefan Karlsson wrote:
> Hi Thomas,
> 
> On 2014-03-03 12:33, Thomas Schatzl wrote:
> > Hi all,
> >
> >    can I have reviews for the following change, another break-out of the
> > 8027295 change (will update its webrev soon).
> >
> > Following Stefan K.'s suggestion, it makes the padding of the fast card
> > cache to avoid false sharing a separate changeset.
> >
> > It adds a new class in padding.inline.hpp which performs allocation and
> > the padding of the data structure.
> >
> > Webrev:
> > http://cr.openjdk.java.net/~tschatzl/8035815/webrev/
> 
> Thanks for breaking this out into a separate change set and for moving 
> the padding to the padded.* files.
>[...]
> http://cr.openjdk.java.net/~tschatzl/8035815/webrev/src/share/vm/memory/padded.hpp.frames.html
> 
> - The "Jagged" part of the PaddedJagged2DArray indicates that the rows 
> are of different length, which isn't the case. Can we rename it to just 
> Padded2DArray?

It's not a true 2d "dense" array. I could not find a good name. For now
I renamed it to Padded2DArray though (which was the original name, but
oh, well :)

> - Your indentation are off by one. See the code above in the file.
> 
> http://cr.openjdk.java.net/~tschatzl/8035815/webrev/src/share/vm/memory/padded.inline.hpp.frames.html
> 
> - Could you add some blank lines to make the code less compact? For 
> example, at line 59, 65, and 74.
>
> Otherwise, this looks good to me.

All done. http://cr.openjdk.java.net/~tschatzl/8035815/webrev.1

Thanks,
  Thomas