Make prev and next pointer in pages list AtomicWords and access them using acquire/release semantic…

Make prev and next pointer in pages list AtomicWords and access them using acquire/release semantics.

BUG=
R=jarin@chromium.org

Committed: https://code.google.com/p/v8/source/detail?r=19332

[Jarin, 2014-02-12 14:06:39]

lgtm with a nit.

https://codereview.chromium.org/150413009/diff/30001/src/spaces.h
File src/spaces.h (right):

https://codereview.chromium.org/150413009/diff/30001/src/spaces.h#newcode685
src/spaces.h:685: AtomicWord prev_chunk_;
Perhaps it would be better to add a comment describing the type of the
AtomicWords (i.e., MemoryChunk*). 

Should not next_chunk_ and prev_chunk_ be private?

[Hannes Payer (out of office), 2014-02-12 15:33:19]

https://codereview.chromium.org/150413009/diff/30001/src/spaces.h
File src/spaces.h (right):

https://codereview.chromium.org/150413009/diff/30001/src/spaces.h#newcode685
src/spaces.h:685: AtomicWord prev_chunk_;
On 2014/02/12 14:06:39, jarin wrote:
> Perhaps it would be better to add a comment describing the type of the
> AtomicWords (i.e., MemoryChunk*). 
> 
> Should not next_chunk_ and prev_chunk_ be private?

Done.

[Hannes Payer (out of office), 2014-02-12 15:40:30]

Committed patchset #3 manually as r19332 (presubmit successful).

[Jarin, 2014-02-12 15:43:32]

On 2014/02/12 15:33:19, Hannes Payer wrote:
> https://codereview.chromium.org/150413009/diff/30001/src/spaces.h
> File src/spaces.h (right):
> 
> https://codereview.chromium.org/150413009/diff/30001/src/spaces.h#newcode685
> src/spaces.h:685: AtomicWord prev_chunk_;
> On 2014/02/12 14:06:39, jarin wrote:
> > Perhaps it would be better to add a comment describing the type of the
> > AtomicWords (i.e., MemoryChunk*). 
> > 
> > Should not next_chunk_ and prev_chunk_ be private?
> 
> Done.

lgtm.

thanks, ship it!