710504 - Provide a way to drop memory that doesn't require allocating memory

Status: RESOLVED WONTFIX

(Core :: JavaScript Engine, defect)

Description

[Nicholas Nethercote [inactive]]

On memory pressure, the JS engine does a GC, which as well as cleaning up the heap drops various other things like JIT code.  It would be nice if we could drop things without having to do the GC, because doing a GC can require us to allocate memory before any is dropped.

Comment 1

[Bill McCloskey [inactive unless it's an emergency] (:billm)]

For the most part, the JS engine should not allocate memory during a GC. I know of one place where we remove elements from hashtables, which can cause memory allocation. But generally we try to allocate everything up front. CC may be different.

Comment 2

[Andrew McCreight [:mccr8]]

The CC allocates a ton of memory.

Comment 3

[Nicholas Nethercote [inactive]]

Eh, doesn't seem that important now.