Fixing Heap::Available() to return total of all spaces.

Fixing Heap::Available() to return total of all spaces.

The Heap::Available method adds up the available size from only 4 of
the spaces. This CL fixes the method to return total of all spaces.

BUG=481504
LOG=N

Committed: https://crrev.com/3f162d416e32caad3f28006c213227bb0e945128
Cr-Commit-Position: refs/heads/master@{#28566}

[ssid, 2015-05-19 10:57:23]

ssid@chromium.org changed reviewers:
+ jochen@chromium.org, rmcilroy@chromium.org

[ssid, 2015-05-19 10:57:24]

Small fix. PTAL

[rmcilroy, 2015-05-19 13:09:53]

rmcilroy@chromium.org changed reviewers:
+ hpayer@chromium.org
- jochen@chromium.org

[rmcilroy, 2015-05-19 13:09:54]

-jochen, +hpayer.

Fix typo in the description.

Otherwise seems reasonable to me, but I'll let Hannes approve incase there is a
reason why it's only returning the 4 spaces currently.

[Hannes Payer (out of office), 2015-05-19 14:55:02]

On 2015/05/19 13:09:54, rmcilroy wrote:
> -jochen, +hpayer.
> 
> Fix typo in the description.
> 
> Otherwise seems reasonable to me, but I'll let Hannes approve incase there is
a
> reason why it's only returning the 4 spaces currently.

Available for lo space returns the amount of memory available by the system
memory allocator. Do you really want that?

[ssid, 2015-05-19 15:27:17]

On 2015/05/19 14:55:02, Hannes Payer wrote:
> On 2015/05/19 13:09:54, rmcilroy wrote:
> > -jochen, +hpayer.
> > 
> > Fix typo in the description.
> > 
> > Otherwise seems reasonable to me, but I'll let Hannes approve incase there
is
> a
> > reason why it's only returning the 4 spaces currently.
> 
> Available for lo space returns the amount of memory available by the system
> memory allocator. Do you really want that?

The only use case of this method right now is at v8IsolateMemoryDumpProvider.
This has an "other spaces" category which shows the memory missed out by the
HeapSpaceStatistics() api (in case more spaces are added in future and the space
stats api is not updated). When I calculate the difference between
heap::Available() and sum of available from spaces, it turns out to be negative
because lo_space isn't counted. What do you suggest is the solution?

[Hannes Payer (out of office), 2015-05-20 08:56:13]

Large object space is special. There is no memory available in this space. Each
object has its own page and leftover memory (because of right trimming) cannot
be reused. Therefore, it calls the system memory allocator and asks if there is
more space available in the system. This is a bit weird, anyhow your cl does
LGTM.

[ssid, 2015-05-21 17:22:16]

The CQ bit was checked by ssid@chromium.org

[commit-bot: I haz the power, 2015-05-21 17:22:40]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1141693003/1

[ssid, 2015-05-21 17:23:02]

On 2015/05/20 08:56:13, Hannes Payer wrote:
> Large object space is special. There is no memory available in this space.
Each
> object has its own page and leftover memory (because of right trimming) cannot
> be reused. Therefore, it calls the system memory allocator and asks if there
is
> more space available in the system. This is a bit weird, anyhow your cl does
> LGTM.

After the discussion offline, I am landing this CL.

[commit-bot: I haz the power, 2015-05-21 18:14:59]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-05-21 18:15:15]

Patchset 1 (id:??) landed as
https://crrev.com/3f162d416e32caad3f28006c213227bb0e945128
Cr-Commit-Position: refs/heads/master@{#28566}