Refactor storage of global handles.

Refactor storage of global handles.

We used to have a linked list of nodes that were internally
block-allocated.

I kept the node blocks and put them on two lists: 1) the list of all
allocated blocks, 2) the list of blocks with used nodes. (1) is used
to reclaim blocks and (2) is used for traversal during GC. To make
traversal on scavenges faster the nodes holding new space objects are
grouped in an auxiliary array.

This changes the minimal memory usage from 5 words per global handle
to 4. Additional word is used for new space handles.

Committed: http://code.google.com/p/v8/source/detail?r=8186

[Vitaly Repeshko, 2011-06-06 12:42:09]

Slava,

This is a cleaned up version of my earlier draft. The only important change is
the introduction of the new space nodes array.


-- Vitaly

[Vyacheslav Egorov (Chromium), 2011-06-06 12:59:22]

LGTM!

http://codereview.chromium.org/7054072/diff/1/src/global-handles.cc
File src/global-handles.cc (right):

http://codereview.chromium.org/7054072/diff/1/src/global-handles.cc#newcode66
src/global-handles.cc:66: // TODO(bug!): if it's a weak handle we should have
invoked its callback.
file a bug?

http://codereview.chromium.org/7054072/diff/1/src/global-handles.cc#newcode717
src/global-handles.cc:717: // TODO(bug!): invoke weak callbacks.
File a bug?

Seems to be a huge change in the API.

http://codereview.chromium.org/7054072/diff/1/src/utils.h
File src/utils.h (right):

http://codereview.chromium.org/7054072/diff/1/src/utils.h#newcode205
src/utils.h:205: typedef T ValueType;
I did not find place where it is used.

[Vitaly Repeshko, 2011-06-06 15:19:43]

Thanks! Submitted.

http://codereview.chromium.org/7054072/diff/1/src/global-handles.cc
File src/global-handles.cc (right):

http://codereview.chromium.org/7054072/diff/1/src/global-handles.cc#newcode66
src/global-handles.cc:66: // TODO(bug!): if it's a weak handle we should have
invoked its callback.
On 2011/06/06 12:59:22, Vyacheslav Egorov wrote:
> file a bug?

Filed http://code.google.com/p/v8/issues/detail?id=1428

http://codereview.chromium.org/7054072/diff/1/src/global-handles.cc#newcode717
src/global-handles.cc:717: // TODO(bug!): invoke weak callbacks.
On 2011/06/06 12:59:22, Vyacheslav Egorov wrote:
> File a bug?
> 
> Seems to be a huge change in the API.

See above. I agree. Let's do this in a separate change.

http://codereview.chromium.org/7054072/diff/1/src/utils.h
File src/utils.h (right):

http://codereview.chromium.org/7054072/diff/1/src/utils.h#newcode205
src/utils.h:205: typedef T ValueType;
On 2011/06/06 12:59:22, Vyacheslav Egorov wrote:
> I did not find place where it is used.

Oops, this got in from another change.

[antonm, 2011-06-06 15:44:40]

DBC

http://codereview.chromium.org/7054072/diff/1/src/global-handles.h
File src/global-handles.h (right):

http://codereview.chromium.org/7054072/diff/1/src/global-handles.h#newcode165
src/global-handles.h:165: // Iterates over all strong and dependent handles.
nit: comment requires an update

http://codereview.chromium.org/7054072/diff/1/src/global-handles.h#newcode177
src/global-handles.h:177: // Iterates over all weak independent roots in heap.
ditto