716598 - [meta] Don't add obviously live objects to the cycle collector graph

Status: NEW

(Core :: Cycle Collector, defect)

Description

[Andrew McCreight [:mccr8]]

If we can tell an object is currently live, then we don't need to add it to the cycle collector graph. The most common instance of this is documents that are currently being displayed. Another example is C++ objects being held alive by marked JS objects. There are also many objects where we can quickly check if they are being held alive by other objects that are obviously alive. Skipping these objects will reduce the size of the cycle collector graph, and avoid traversing their child nodes.  There is a danger of introducing transient leaks that don't show up at shutdown.

Smaug has done a lot of these small patches, and I think it makes sense to gather them together.  Sorry for the bug spam.

Comment 1

[Andrew McCreight [:mccr8]]

Bug 705371 is more not adding obviously acyclic objects to the graph rather than obviously live, but close enough.

Comment 2

[Andrew McCreight [:mccr8]]

Meta bug, doesn't really need a Snappy tag.