How is junk data generated
Window.test =new Object() window.test.a=new Unit16Array()Copy the code
Principles of Garbage Collection
Keywords: Clear, tidy memory
Intergenerational hypothesis:
- Most objects have a short lifetime and live in memory for short periods of time, such as internal function declarations, block-level scopes, and the object is destroyed when the code or function is finished executing.
- Undead objects live longer. Certain objects live in memory for a long time, such as Window objects, DOM objects, Webapis, etc
Two areas: Young Space and Old Space
young space
Storage of temporary small objects corresponds to the first rule of the generation hypothesis
- Sub-garbage collector algorithm:
In two areas: object area, leisure area, object area to store variable, after the object area is full, triggers garbage collection algorithm, garbage and eliminate tag object area, will still alive is copied to the leisure area (also drop in at this time to complete the memory), object area, exchange object area and leisure area, two is not clear, to upgrade to the old space
old space
- Main garbage collector algorithm:
Mark-clear
Tags: Starting from the root node, tags that cannot be traversed clear: Clears inactive objects
Memory fragmentation is easy to occur. How?
Mark-tidy
Move all live objects to one side, then clear the remaining space
