Add an API to V8 to get simple heap statistics.

Add an API to V8 to get simple heap statistics.

Committed: http://code.google.com/p/v8/source/detail?r=3089

[mnaganov (inactive), 2009-10-09 16:14:32]

http://codereview.chromium.org/261037/diff/3001/4005
File src/spaces.h (right):

http://codereview.chromium.org/261037/diff/3001/4005#newcode1268
Line 1268: if (from_space_.is_committed()) return 2 * Capacity();
Ah, I think now I know why "used" space in my heap stats report can have a
greater value than "available". I used to think that it was due to accounting
free lists size to used memory.

[Kevin Millikin (Chromium), 2009-10-19 18:49:38]

LGTM

http://codereview.chromium.org/261037/diff/3001/4002
File include/v8.h (right):

http://codereview.chromium.org/261037/diff/3001/4002#newcode2107
Line 2107: size_t total_heap_size() { return total_heap_size_; }
There's not much gained by making the fields private and having accessors. 
Consider just making them public.

[iposva, 2009-10-19 20:33:42]

Strong opinion on accessors included.

-Ivan

http://codereview.chromium.org/261037/diff/3001/4002
File include/v8.h (right):

http://codereview.chromium.org/261037/diff/3001/4002#newcode2107
Line 2107: size_t total_heap_size() { return total_heap_size_; }
On 2009/10/19 18:49:39, Kevin Millikin wrote:
> There's not much gained by making the fields private and having accessors. 
> Consider just making them public.

I strongly disagree. If you make the fields public you have no control which
code touches the fields directly. By going through an accessor you can abstract
the implementation later without having to hunt down all the clients accessing
the data.

Also, I would suggest that you make the setter private and friend
ImplementationUtilities to allow setting only from within the V8 internal
implementation. This is external access to the field is what Kevin was really
complaining about (I think).